Slyp iJi Hill IGibrarg ]f 3forlli (Earnlina Siate Cnllegf Textiles Special j Collect. TP897 I ^^ H92 1886 [ex. lib. N-C ;'t.-t .s:,E=s S001 95575 W CORNER BOOK SHOP 102 FOURTH AVENUE NEW YORK 3, N. Y. ■'*^<-^i j^^lWai. 'fe^ THIS BOOK MUST NOT BE TAKEN FROM THE LIBRARY BUILDING. MANUALS OF TECHNOLOGY. Edited by Professor Ayrton, F.R.S., and Richard WORMELL, D.Sc, M.A. Ilhafyxded. Awvmgkemt with Original ajtd Practical JJlTisfrations. Dyeing of Textile Fabrics. By Pro£ Hcmmel. 5s. Practical Mechanics. By Prof Peeky, M.E. 35. 6d. Catting Tools 'Worked by Hand and Machine. By Prof. Smith. 3s. 6d. Design in Textile Fabrics. By T. R. Ashenhurst, 4s. 6d. Steel and Iron. By W. H. Greentvood, F.C.S. 55. Spinning Woollen and Worsted. By W. S. E. McLaren. 4s. 6d. Watch and Clock Making. By D. Glasgow. 4s. 6d. Cassell & CoMPAxy, Limited, Ludgate Hill, London, E.G. Manuals of Technology. EDITED BY Prof. Ayrton^ F.R.S.^ and R. Wormell^ D.Sc.y M.A. The Dyeing OF Textile Fabrics. BY J. J. HUMMEL, F.C.S., PHOFESSOE AND DIRECTOR OP THE DYEING DEPARTMENT OF THE YORKSHIRE COLLEGE, LEEDS. WITH 97 DIAGRAMS. SECOND EDITION. CASSELL & COMPANY, Limited LONDON, PARIS, NEW TORK & MELBOURNE. 1886. [all RIGHTS RESERVED.] IWE BOOKCASE ^0 THE WOESHIPFUL COMPANY OF CLOTHWORKERS OF THE CITY OF LONDON, AMONG THE EARLIEST AND MOST MUXLFICEXT PATRONS OF TECHNICAL EDUCATION IN ENGLAND, THIS WORK 18, BY PERMISSION, RESPECTFULLY INSCRIBED BY THE AUTHOR. 97490 P E E F A C E . The object of this Manual is to provide the teacher and student of Dyeing with a useful text-book giving exact scientific and practical information. It is intended also to supply the Dyer with explanations of the scientific principles involved in the operations of his art, in order that he may take a more intelligent interest in his work, and be stimulated to criticise it, and to determine, by means of well-devised experiments, whether his methods are rational and incapable of improvement, or the reverse. Certain details have been furnished relatinsr to the mode of applying the various Colouring Matters and Mordants, but these must not be regarded as fixed and unchangeable receipts, but rather as starting-points for further experimental work. The Art of Dyeing being a special branch of Chemical Technology, no apology is offered for leavening the work with a wholesome amount of chemistry. The Dyer is Specially urged to make himself acquainted with the general principles of chemical science, for assuredly the more such knowledge is brought to bear upon every detail of the art, the more rapid will be its progress. It seemed necessaiy to give the somewhat complex chemical symbols and scientific names of the Coal-Tar colours in order to identify them, since, in the course of time, many of the present commercial names may be re- placed by others, or applied to colouring matters not yet introduced. The advanced student will find them useful, for they show at a glance the chemical relationships VUl DYEING OF TEXTILE FABRICS. existing between colours which possess similar dyeing properties. The metric system of weights and measures has been adopted because of its advantages both to the teacher and the student of Dyeing, and it is now becoming more and more generally known and appreciated. For those who prefer the English system, however, tables of equiva- lents are given at the end of the volume. Considerable care has been bestowed upon the arrangement of the subject matter, to prevent, on the one hand, confusion arising in the mind of the reader as to which fibre is being referred to in any given connection, and, on the other, to enable comparisons to be readily made of the treatment to which each fibre — cotton, wool, or silk — is submitted when applying any given colouring matter or mordant. To my old and valued friend. Prof. L. Liechti, of "Vienna, I tender my best thanks for his friendly criti- cisms during the progress of the work, and his kind assistance in the revision of the proofs. My obligations are also due to those Colour-Manu- facturers and Engineers whose names are mentioned in the text, and also to the proprietors of the Textile Manu- facturer, for the loan of a complete set of their well- known journal. All the principal English and foreign standard works and journals on dyeing have been consulted, and the information has, as far as possible, been brought down to the latest date. J. J. H. Yorkshire College, Leeds. October, 1885. CONTENTS. -•o*- FIBRES. CHAPTEB PAGB I. — CoTTO:!f 1 II. — Flax, Jute, and China Grass . . . .12 III.— Wool 22 IV.— Silk 43 OPERATIOXS PRELIMINARY TO DYEING. V. — Cotton Bleaching ... . . 71 VI. — Linen Bleaching .... . . 86 VII. — Wool Scouring and Bleaching . . . .91 VIII. — Silk Scouring and Bleaching , . . .115 WATER IN ITS APPLICATION TO DYEING. IX.— Water 121 THEORIES OF DYEING. X. — About Dyeing 144 MORDANTS. XI. — Use of Mordants 156 METHODS AND ]\IACHINERY USED IN DYEING. XII. — N0TE8 on Cotton, Wool, and Silk Dyeing . 248 X DYKrSG OF TEXTILE FABRICS. APPLICATIOX OF THE NATURAL COLOURING :viATTEES. CHAPTEE PASB XUr.— BiT2 CiTi^iz Matteks 295 Xrr.— Eet. C:L:":iyc- ^Iatteb5 338 XV.— T^LLC^ C:i:r7-i>-c- [Matter* .... 356 APPLICATION OP THE ARTITICIAL COLOUlLDfG MATTERS. Xn. AXILIVE CoLOrEEfG Hattebs .... 37S XV iL — QrcfoiETB CoLOTTRixG Mattebs . XV 111. PffESrOI, CoLOtTREfG MaTTEBS \l \. — Axo CoioraixG Mattebs .... XX. — Akthbacestb Coloxtbtstg Matters XXT, — ^Abtificiai, CoLorKixG Mattebs costaisjsg SrXr- PHTB. ....... 397 398 412 425 459 APPLICATION OF THE MINERAL COLOURIXa MATTERS. XXn. — Chbome Yeexow — ^Ibox Bctf — Maxgaxtsx BBOinr — ^Pbussia^; BtrE 461 THE DYEIXG OF MIXED FABRICS. X \ I n — Fabbics of CoTTOjf A3rD Wool .... 466 EXPERIMZXTAL vYEISG. XXIV. — Method op Detisdcg Expkrimkxts ix Dteixg . 473 XXT. — EanMATiox of the Talos of Coloubixg Mattebs 492 XXVI. — The Dbtectiox of Coiocbs ox Dyed Fabbics . 497 Tables of Colouk Tesis 498 Tables of Thebmojceteb Scales, "Weights axd IbtASTBSSy Sdc 526 LIST or ILLUSTEATIONS. PAGE Cotton Plant 1 Appearance of Cotton under the Microdcope 3 Transverse Sections of Cotton Fibre 3 Transverse Sections of Unrine Cotton Fibre 3 Transverse Sections of Cotton Fibre after Treatment with Caustic Soda 9 Flax Plant, A; Flower, b; Fruit, c 13 Flax Fibre under the Microscope 1° Microscopical Appearance of Wool Fibre 24 Cells of Wool Fibre under the Microscope 25 Cross Section of Typical Wool Fibres 26 Silk Moth (Bombya; mori) 43 Silkworm on Mulberry Leaf 44 The Silk Glands of the Silkworm 45 Section of Silk-bag 46 Microscopic Appearance of E.aw Silk Fibre 46 Silk Cocoon 47 Silk-reeling Machine 49 Microscopic Appearance of Tussur Silk Fibre 52 Stringing Machine for Silk 54 Details of Silk-stringing Machine 56 Silk-lustreing Machine . . ^ Conditioning Apparatus 60 Section of Conditioning Chamber 61 Apparatus for Chemicking, Souring, and Washing 74 Plate-singeing Machine 76 Barlow's High-pressure Kiers 79 Section of Injector Kier 82 Wool-steeping Tanks 96 Wool-steeping Tanks 97 Sectionof Furnace for Making Yolk-ash 98 Pake Wool-scouring Machine 100 Yarn-stretching Machine 103 Woollen Yarn-scouring Machine 104 Continuous Woollen Yarn-scouring Machine 105 Woollen Cloth-scouring Machine 106 Section of ditto 107 Woollen Cloth open-width Scouring Machine 109 Treble Crabbing Machine HO Sulphur Stove for Woollen Cloth Bleaching 113 Plan of Porter-Clarks Apparatus for Softening Water . . . .132 Porter-Clark's Apparatus for Softening Water (elevation) , . .133 Gaillet and Huet's Apparatus for Softening Water 135 Gaillet and Huet's Precipitating Tank 136 Plan of Purification Works for Waste Dye-liquors 140 Mordanting Bath for Silk 186 Squeezing Machine used in the Mordanting of Silk 187 Washing Machine used for Silk . . . ' 189 XLU DYEING OF TEXTILE FABRICS. TASK Hank^yeing Machine 251 Section of ditto 251 Boden's Hank-djeing Maciiine 25Z Warx>-dyeuigr Machine 253 Wash-stocks 254 Scotch Hank-washing Machine 255 Plan of ditto 255 German Hank-washing Machine 257 Perspective View of ditto 253 Continuous Hani-diying Machine 259 Spiral Dyeing Machine 261 Lancashire Jigger Dyeing Machine 362 Washing Machine for Calico 263 Side View of ditto 264 Square-beater Washing Machine 265 Squeezing Eollers 265 Birch's Squeezing Eoller (front view) 266 Bide View of ditto 267 Hot-air Drying Machine 263 McXaught's Wool-drying Machine (section) 277 Ditto (side view) . ' 278 Continuous Wool-drying Machine 279 Woollen Yam Dyeing Machine 279 Pitts Woollen Tarn Dyeing Machine 280 Hydro-extractor 2S1 Arrangement for Drying Yam in the Open Air 282 Pair of Winch Dyeing Machines for Cloth 282 Union Cloth Dveins Machine (front elevation) 233 End Elevation of Ditto 2S3 Woollen Cloth Squeezing Machine 2S4 Side View of ditto 285 Cylinder Drying Machine 296 Tentering Machine 287 Indigo Grinding Mill 296 Continuous Indigo Dveing Machine 301 WoadVat . . ' 305 Apparatus for Preparing Hydrosulphite Vat Liquor .... 310 Amlitie Black Dyeing Machine 393 Turkey-red Yam-wringing Machine 428 Tramping Machine for Turkey-red Yam 430 Clearing Boiler 433 Plan of Ditto 434 Hydraulic Press 435 Oil-padding Machine 439 Section of Liquor-padding Machine 440 Ground Plan and Sectional Elevation of Turkey-red Stove ... 441 Steaming-chest for Turkey-red Yarn 445 Plan and Elevation of Continuous Steaming-chest 447 Plan and Elevation of Experimental Dyeing Apparatus .... 433 Section of ditto 464 Dyeii^g of Textile Fabrics. F I B E E S . CHAPTER I. COTTON. 1. The Cotton-Plant. — Cotton is the white, downy, fibrous substance which envelopes the seeds of yarious species of the cotton- plant, Gossypmm, be- longing to the natural order Malvacece. The seeds, to which the cot- ton fibres are attached, are enclosed in a 3- to 5-valved capsule^ which bursts when ripe; the cotton is then collected and spread out to dry. The seeds are after- wards separated by the mechanical opera- tion termed " gin- ning," and the raw cotton thus obtained is sent to the spinner. The cotton-plant (Fig. 1) is cultivated with There are numerous varieties '^^^t^'^'cTH, HILL LIBRARY North Carolina State College Cotton Plant. success only in warm climates. , of which the following are 2 DYEING OF TEXTILE FABRICS. (Chap. I. (1) Gossypium harhadeiise. — An lierbaceous plant, beai-ing a yellow flower, and attaining a height of 4—5 metres. A Tariety of this species yields the Sea Island cotton, mnch prized on account of the great strength, length, and lustre of its fibres. It is grown in the North American States of South Carolina, Georgia, and Florida, and on the neighbouring islands of the West Indies. (2) Gossypium hirsutuin. — A hairy, herbaceous plant, about 2 metres high, with pale yellow or almost white flowers. It is grown in the States of Alabama, Louisiana, Texas, and Mississippi. (3) Gossypium herbaceum. — A small herbaceous plant, 1 metre high, and bearing yellow flowers. Varieties of this species are grown in India, China, Egypt, and America. The Madras, Surat, and short-stapled Egyptian cotton, also some American cottons, are obtained from this species. (4) Gossypium peruvianuni. — This species, a native of South America, grows to a height of 3-5 metres, and bears a yellow flower. It yields the long-stapled and much esteemed Peruvian and Brazilian cottons. (5) Gossypium religiosum. — This is a low annual shrub, about 1 metre high, and bearing a yellow flower. It is grown in China and India, and yields the so-called Nankin cotton, remarkable for its tawny colour. (6) Gossypium arhoreum. — This is a perennial tree, growing to a height of 6-7 metres, and bearing reddish- purj:»le flowers. It is a native of India, and produces a good quality of cotton. 2. Physical Structure. — If cotton wool is examined under the microscsope, it is seen to consist of minute fibres. Their general appearance is that of spirally- twisted bands, having thickened borders and iiTegular markings on the surface (Fig. 2). In the better qualities of cotton — e.g.. Sea Island — the spiral character is less Chap. I.] SECTIONS OF COTTON FIBRE. prominent. Transverse sections of the fibres show them to be flattened tubes, ha\dng comparatively thick walls and a small central opening (Fig. 3). A single cotton fibre is^ in- deed, an elongated, tapering, and collapsed plant-cell, the thin end of which is closed, and the other (namely, that by which it was attached to the seed) irregularly torn. Sometimes broad ribbon- like fibres may be noticed, which are remarkably transparent, and possess irregular folds. Their transverse section exhibits no central opening at all (Fig. 4). They are, indeed, unripe fibres, in which no separation of the thin cell walls has yet taken place. They refuse to be dyed Fig. 2. — Appearance of Cotton uuder the Microscope. Fig. 3. — Transverse Sections of Cotton Fibre. like ordinary ripe fibres, and appear occasionally as white specks in indigo- and madder -dyed calicoes ; hence the name dead cotton has been given to them. In half-ripe cotton fibres the cell walls are still so closely n^^^^ Fig. 4.— Transverse Sections of Unripe Cotton Fibre. pressed together that the ultimate central canal is indi- cated in a transverse section only by a fine line. When steeped in water, however, such fibres gradually swell up and form hollow tubes. Cotton fibres vary in length from 2-5 to 6 centimetres, and in breadth from O'OIT to 0-05 millimetres. 4 DYEIXG OF TEXTILE FABRICS. [Chap. I. The spiral character of the fibre makes it possible to spin exceedingly fine yam, and also accounts for the elastic character of calico as compared with linen, the fibres of which are stiff and straight The microscopic appearance of cotton serves to distinguish it from other vegetable and animal fibres. 3. Chemical Composition. — The substance of the cotton fibre is «illed Cellulose. This is almost nniversal in vegetable cells, forming the so-called lig- neous matter or woody fibre of plants, but whereas in woody fibie tihe cellulose is encrusted with a large proportion of foreign matter — such as dried- up sap, resin, ' ^^^^^ \2J Jolin Mercer, Fig. 5.— Transverse Sections of Cotton Fibre after tliscovered that Treatment with Caustic Soda. Calico treated in the above man- ner was not only stronger than before, but had also acquired an increased attraction for colouring matters. Hoping to apply the process with advantage prepara- tory to dyeing, he patented it. Cotton thus treated IS said to be Mercerised. When dyed in the indigo- vat, mercerised calico requires only one dip to produce as deep a shade of blue as can be obtained on ordi- nary calico only after five or six dips. Again, if a piece of ordinary and a piece of mercerised calico be dyed 10 DYEING OF TEXTILE FABRICS. [Ctap. I. alizarin red, making all other conditions (e.g., time, tem- perature, quantity of Alizarin, &c.) the same in both cases^ the mercerised cloth will be found to have a much fuller and richer colour than the other. Similar differ- ences in depth of shade are noticed with other colours. The process, however, has never been adopted in general practice, since the excessive contraction which the cloth undergoes, amounting as it does to one-fifteenth in length and in breadth, and the fact that in most cases the same result can be obtained in other ways, did not seem to warrant the expense. Caustic ammonia in aqueous solution, whether strong or weak, has under all circumstances no action on cotton. Dry cotton is said to absorb one hundred and fifteen times its bulk of ammonia gas. Solutions of the carbonates of j^otash, soda or ammonia, silicate of soda, borax, and soap, have practically no action on cotton. There is a case on record, however, in which calico impregnated with silicate of soda, and shipped from England to South Africa, was found, after having been packed in bales for two years, to have become tender. Examination showed that the silicate of soda had decomposed with formation of silicic acid and carbonate of soda, and it was concluded that the tender- ing was due partly to the long-continued action of the carbonate of soda on the cotton, and partly to disruption of the fibres by the expansive force of the crystallisation of the carbonate of soda formed within them. The ex- planation is not altogether satisfactory^ since it was found impossible to produce the same effects artificially. Pro- bably it was a case of oxidation of the fibre. Whatever may have been the real cause, it is well to bear in mind that under exceptional conditions like those mentioned, even apparently harmless salts may tender the cotton fibre. 8. Action of Lime. — Milk of lime, even at a boiling heat, has little or no action upon cotton so long as the latter is steeped below the surface of the liquid, but if it is at the same time exposed to the action of air or Chap. I.l ACTION OF CHLORINE ON COTTON. 1 1 steam, it becomes much tendered by oxidation of the fibre. Such exposure must be avoided in cotton- bleaching. 9. Action of Chlorine and Hypochlorites on Cotton. — Cotton is quickly tendered if exposed to moist chlorine gas, especially in strong sunlight. The action may be due partly to the direct action of chlorine upon the fibre, one portion combining with and another replacing some of its hydrogen, partly to the destructive action of thehydrochloric acid thus produced, and partly to oxidation. Solutions of hy2:)Ochlorites (bleaching-powder, &c.) tender cotton more or less readily, according to the strength and temperature of the solutions and the duration of their action. Even a very weak solution of bleaching-powder will tender cotton if the latter be boiled with it; but when used cold, even if it be at the same time exposed to the air, the destructive action is inapjDreciable, and confined merely to bleaching tlie natural colouring matter of the cotton. If a piece of calico is moistened wdth a solution of bleaching-powder at 5° Tw. (Sp. Gr. 1*025), then exposed to the air for about an hour, and Avashed, it w^ill be found to have acquired an attraction for basic coal-tar colouring matters similar to that possessed by the animal fibres. Cotton thus treated also decomposes directly the normal salts of aluminium, iron, &c., attracting metalKc oxide. Experi- ment has shown that this remarkable change is due to the action of the hypochlorous acid liberated by the car- bonic acid of the air. The cotton thereby becomes chem- ically changed to what has been called by Witz, its discoverer, Oxy-cellulose. 10. Action of Metallic Salts. — Under ordinary cir- cumstances, solutions of neutral salts have no action on cotton ; even those of acid salts have no appreciable effect if the cotton be merely steeped in them while cold; but if boiled with them the effect is similar to that of the free acids, though slightly less marked. If cotton is impregnated with solutions of the salts of the earths and heavy metals, then dried, and heated or steamed, the salts 12 DYEING OF TEXTILE FJiBRICS. [Chap. L are readily decomposed ; a basic salt is precipitated on the fibre, and the liberated acid afiects the fibre ac- cording to the nature and strength of the salt solution employed. The use of aluminium chloride, which was at one time recommended for the pui-pose of destroying the cotton in rags containing cotton and wool (" extracting '"), also the application of the " topical ''' or '•' steam colours," and the *•' mordanting *' process employed by the calico-pi'inter, are all based upon the above facts. 11. Action of Colouring Matters. — With few excep- tions, colouring mattei^ are not directly atti^cted from their solutions by the cotton fibre, hence it is not readily dyed, and special means of prepai-ing it to receive the dyes have to be adopted in most cases (mordanting). The reason of this inert character of cotton is not yet satisfactorily explained ; probably both its chemical and physical structure have an influence in the matter. CHAPTER 11. FLAX, JTTE. AND CHDTA GRASS. 12. Flax-plant. — The term '•' flax " is employed to designate the flax or linen fibre and cilso the plant fi'om which it is obtained. Linen fibre consists of the bast cells of certain species of the genus Linum, more par- ticularly Z{72?/«i usiiatissimum (Fig. 6), a plant belonging to the natural order Liimc^oe, and cultivated in nearlv all parts of Eui'ope. It is an herbaceous plant, having a thin, spindle- shaped root, a stem usually branched at the top, smooth lanceolate leaves, and bright blue flowers. The time of sowing varies in diflerent countries from Cliap. n.] THE FLAX PLANT. 13 February to April, consequently the time of harvest also varies, and may be from June to September. If the object of the farmer is to obtain good fibre, and not seed for re-sowing, the plant is gathered before it is fully matured — namely, when the lower portion of the stem (about two- thirds of the whole) has become yellow, and the seed cap- sules are just chang- ing from green to brown. At this stage the plants are carefully pulled up. If the plants are left in the ground till the whole stem is yellow — i.e., till the plant is fully ripe — the fibre afterwards ob- tained will be more stiff and coarse. The freshly- pulled flax is at once submitted to the process of "rip- pling," which has for its object the removal of the seed capsules. This operation is performed by hand, by drawing successive bundles of flax-straw through the upright prongs of large, fixed iron combs, or " ripples." If the pulled flax has been dried and stored, the remo^'al of the seeds is usually effected by the seeding-machine, which consists essen- tially of a pair of iron rollers, between which the flax- straw is passed. Fig. 6.— Flax plant, a; flower, b; fruit, c. 14 DYEING OF TEXTILE FABRICS. [Cliap. TI. 13. Retting. — The most important operation in separating the fibre is that of "retting," the object of which is to decompose and render soluble by means of fermentation, as well as to remove, certain adhesive substances which bind the bast fibres not only to each other, but also to the central woody portion of the stem, technically termed the " shive," " shore," or " boon." The various modes of retting may be classified as follows : — (1) Cold-water retting. This may be carried out either with running or with stagnant water. (2) Dew retting. (3) Warm-water retting. Cold-water letting. — The best system of retting in running water is said to be practised in the neighbour- hood of Courtrai, in Belgium, where the water of the sluggish river Lys is available. The bundles of flax straw are packed vertically in large wooden crates lined with straw. Straw and boards are afterwards placed on the top, and the crate thus charged is anchored in the stream and weighted with stones, so that it is submerged a few inches below the surface. In a few days fermentation begins, and as it proceeds additional weight must be added from time to time, in order to prevent the rising of the crates through the evolution of gas. As a rule, after steeping for a short period, the flax is removed from the crates, and set up in hollow sheaves to dry; it is then repacked in the crates, and again steeped until the retting is complete. According to the temperature, quality of flax, &c., the duration of the steeping may be from ten to twenty days. The end of the process must be accurately determined by occasionally examining the appearance of the stems, and applying certain tests. The flax bundles should feel soft^ and the stems should be covered with a greenish slime^ easily removed bypassing them between the finger and thumb ; when bent over the forefinger the central woody portion should spring up readily from the fibrous sheath. If a portion of the fibre is separated from Chap. 11.] FLAX RETTING. 15 the stem and suddenly stretched, it should draw asundei ■s\ith a soft, not a sharp, sound. When the retting is complete, the flax is carefully removed from the crates and set up in sheaves to dry. Retting in stagnant vxiter is the method usually adopted in Ireland and Russia. The flax in this case is steeped in ponds, situated near a river if possible, and provided with suitable arrangements for admitting and runnincj off the water. This mode of retting is more expeditious than when running water is employed, because the organic matters retained in the water very materially assist the fer- mentation ; there is, however, always a danger of " over- retting," that is, the fermentation may become too energetic, in which case the fibre itself is attacked and more or less weakened. This danger is minimised by occasionally changing the water during the steeping process. The quality of the water employed in retting is of considerable importance ; pure soft water is the best, calcareous water being altogether unsuitable. The waste flax water, being strongly impregnated with decomposing organic matter, poisons the streams into which it may run, and destroys the fish ; but it possesses considerable value as a liquid manure. After retting in stagnant water, the flax is drained, then thinly spread on a field ; it is left there for a week or more, and occasionally turned over. This j^rocess is termed "spreading," or "grassing." Its object is not merely to dry the flax, but to allow the joint action of dew, rain, air, and sunlight to complete finally the destruc- tion and removal of the adhesive substances already alluded to. After a few days' exposure the stems begin to " bow," the fibrous sheath separates more or less from the woody centre, and the latter becomes friable. Dew retting simply consists in spreading the flax on the field and exposing it to the action of the weather for six or eight weeks, without any previous steeping. Damp weather is the most suitable for this 16 DYEIXG OF TEXTILE FABRICS. (Chap. II. metliod, since all fermentation ceases if the flax becomes diy. Dew retting is practised largely in Russia and in some parts of Germany. Warm-ioater retting was a system recommended in 1847 by R. B, ScLenck. It consists in steeping the closely packed flax bundles in covered wooden vats, filled with water heated to 25^ — 35^ C. By this means the fer- mentation is much accelerated, and the operation is completed in two or three days ; the process seems, how- ever, to have met with only Kmited success. Of chemical retting processes, that recommended by R. Baur may be mentioned. It consists in first squeezing the fresh or dried flax straw between rollers, and then steeping it in water till the latter ceases to be coloured yellow. It is next drained and steeped for one or two days in dilute hydi'ochloiic acid (3 kilos, concentrated HOI per 100 kilos, flax), until the bast fibres can be readily separated. The acid Liquid is then run off*, and the flax is well washed with shghtly alkaline water, or such as contains a little chalk. A fuither treatment with dilute bleaching powder solution to dissolve away still adhering woody matter, and a final washing, complete the process. A well-retted flax is said to be thus obtained in the course of a few days only. 14. Chemistry of Retting. — Expeiiments by Kolb in- dicate that the adhesive matter which cements the flax fibres together is essentially a substance called pectose. During the retting process the fermentation decomposes this insoluble i>ectose, and transforms it into soluble pecfiJie, and insoluble jyecfic acid. The former is washed away, the latter remains attached to the fibre. 15. Breaking. — The next operation is to remove the woody centre from the retted and dried flax, after which the fibres must be separated from each other. It is rather beyond the province of this manual to give more than a genei'al account of the nature of the various mechanical operations for eflecting this. They comprise "breaking," "scutching," and "hackling." Chap. II.] FLAX HACKLING. 17 The first operation aims at breaking up the brittle woody centre of the flax into small pieces, by threshing it with an indented wooden mallet, or by crimping it with a many-bladed " braque." The operation is now exten- sively done by machinery, the flax being passed through a series of fluted rollers. 16. Scutching. — In this process handfuls of the flax are beaten with a broad wooden scutching-blade ; the particles of woody matter adhering to the fibres are thus detached ; and the bast is partially separated into its constituent fibres. Scutching is also performed by machinery. The waste fibre obtained is called '^ scutching tow," or "codilla." 17. Hackling. — The subsequent Hackling, or Heck- ling, has for its object a still further separation of the fibres into their finest filaments, by combing. When done by hand, a bundle of flax is drawn, first one end and then the other, through a succession of fixed upright iron combs or " hackles " of difl'erent degrees of fineness, beginning with the coarsest. When machinery is used, the flax is held aoainst hackles fixed on movinst belts or bars or on the circumference of revolving cylinders. The product of the operation is twofold, namely, "line" and " tow " ; the former consists of the long and more valuable fibres, the latter of those which are short and more or less tangled. 18. Flax- Line. — The appearance of flax-line is that of long, fine, soft, lustrous fibres, varying in colour from the yellowish-buff* of the Belgian product to the dark greenish-grey of Russian flax. This difference in colour is chiefly owing to the system of retting adopted. Flax retted in running water has a more or less pale yellowish-buff" colour, while that retted in stagnant water possesses a greyish colour, probably because of the presence of the decomposing organic matter in the water. 19. Physical Structure and Properties. — Examined under the microscope, a single flax fibre appears (Fig. 7) c 18 DYEING OF TEXTILE FABRICS. [Chap. n. as a long, straight, transpai*ent tube, often striated longitudinally j it possesses thick walls, and an exces- sivelv minute central canal. At in-egular intervals it is slightly distended, and at these points faint transverse markings may be detected. When examined with high powers, they seem to consist of a succession of very minute fissiu'es, and, according to Vetillart, are simply breaks, or wrinkles, produced by a bending of the fibre, and not cell divisions, or nodes, as frequently stated. Fibres which have been vigorously rubbed between the fijigei*s, or have l^een subjected to the lenorthened disinteca*atincr action of alkalis, exhibit well-marked longitudinal fissures, and the broken end of a well-worn fibre presents the aspect of a bundle of fibrils. These appearances evidently indicate that the cell wall of the linen fibre possesses a fibrous structure. The a^"erage lens^h of a Fi£ Flax Fibre under the Microscope. On IS I'o— 30 niilli- the average breadth 0-020-0 -025 milli- single fibre metres, and metres. In transvei^e section, the linen fibre shows a more or less rounded polygonal contovu'. The chief physical characteristics of the linen fibre, when freed from all enci-usting material, are its sno'^y whiteness, silky lustre, and great tenacity. This last feature is no doubt owing to its fibrous texture as well as to the thickness of the cell walls. Its straight, even, prismatic, and transparent character accounts largely for the lustre. Linen is hygrometric to about the same degree as cotton, and contains, when air-diy, about 3 per cent, of moisture. It is, however, a much better conductor of heat, and therefore feels colder than cotto3i. It is also less pliant and less elastic. Cliap. II.] PHYSICAL STRUCTURE OF FLAX. 19 20. Chemical Composition. — Treated with sulphuric acid and iodine solution, the thick cell wall is coloured blue, while the secondary deposits, immediately enclosing the central canal, acqmre a yellow colour. The linen fibre consists therefore essentially of cellulose, but in its raw unbleached state it is mixed with about 15—30 per cent, of foreign substances, chief among which is pectic acid. Fatty matter, to the extent of about 5 per cent., colouring matter, and other substances not investigated^ are also present. Action of various Agencies on Flax. 20* — Being cellulose, the action of various chemical agents on pure linen fibre is much the same as on cotton, but generally speaking, linen is more susceptible to disintegration, especially under the influence of caustic alkalis, calcium hydrate, and strong oxidising agents, e.g., chlorine, hypochlorites, &c. As to the action of these agents on the encrusting materials of retted flax, boiling solutions of caustic and carbonated alkalis saponify and remove the fatty matter, and also decompose the pectic acid and any pectose which may have escaped the action of the retting pro- cess. Under their influence the insoluble pectic acid is changed into metapectic acid, which at once unites with the alkali to form a soluble compound. By successive boiling with alkali the fibre entirely loses its brownish colour, and retains only a pale grey shade, readily bleached by hypochlorites. The system of bleaching linen is based on these reactions. Water-retted flax (whether retted in running or stagnant water, it matters not) is capable of being well bleached. Under the influence of boiling alkalis it always assumes a lighter colour, and when submitted to the reducing action of stannous chloride it acquires a yellowish tint. Dew-retted flax, on the contrary, bleaches with much difficulty. When boiled with alkalis it becomes darker, and stannous chloride has little or no efiect on it. 20 DYEIXG OF TEXTILE FABRICS. [Chap. H. These reactions may serve to discover by wliich process of retting the fibre has been obtained- The linen fibre is even less readily dyed than cotton, a fact which, althongh well known to dyers, has not yet been satisfactorily f-xplained. Its physical structure and the possible presence of pectic matters no doubt exercise some resizaining influence. 21. Jnte consists of the bas-t fibres of various species of Corehonis (e.g., C. olitorius, C. capsul-aris, (tc), belong- ing to tlie family of the Tiliacece, and is mainly cultivated in BengaL The fibre is separated from the plant by pit)oesses grmilar to those employed in obtaining the flax Sbre, nanftdy, rcAJ&ng, beating, washing, drying, i:c. The raw fibrie, as exported, consists of the upper five-sixths of the isolated bast, and occurs in lengths of about seven fedL Under the microscope, it is seen to consist of bundles of stiff, lustrous, cylindrical fibrils, having irregularly -thickened walls, and a comparatively large central opening. The colour of the fibre varies from Ihowii to silver-grey. It is distinguished from fiax by b^ng colonred yellow, under the influence of sulphuric add and iodine solution. According to Cross and Be van, the substance of the jnte fibre is not cellulose, but a peculiar derivative of it, to which the name hastose has been given. Under the influence of chlorine, a chloiinated compound is produced, which, when sultmitted to the aerLsive, wliile the ordin- aiy retting process is not thoroughly effective, because of the succulent nature of the stem, and the large amount and acridity of the gummy matters, which rapidly coagidate and become insoluble on exposm'e to au\ The chief characteristics of the fibre are its excessive strength and durability, fineness, silky lustre, and pure white colom\ Sulphuric acid and iodine solution colour it blue, hence it seems to consist essentially of cellulose. Under the microscope, the fibres appear stiff and straight, the cell walls exhibiting a fibrous texture, and varying in thickness in different parts of the fibre. CHAPTER III. WOOL. 23. Varieties of Wool. — By the term "wool" we describe the haiiy covering of several species of mam- malia, more especixiUy that of the sheep. It differs from hair, of which it may be regaurded as merely a variety, by being, as a inile, more flexible, elastic^ and ctu'ly, and because it possesses certain details of surface-structure which enable it to be more readily matted together. Many mammalia have both wool and haii-, and it is probable that this has also been the case with the sheep in its original wild state, but under the influence of domestication the rank hairy fibres have largely dis- appeared, while the soft under-wool round their roots has been siugularly developed. At so early a date was the sheep domesticated — as remote, indeed, as the prehistoric period of the Cave Dwellers, — that it has l>een found impossible to determine with ceriainty its tJTie origicL By some the parent stock is considered to Chap, m.] WOOLLEN AND WORSTED GOODS. 23 be the Ovis amnion of the mountains of Central Asia, where the tribes have always been pastoral in their habits and occupations. The climate, breed, food, and rearing of the sheep, all influence the quality of the wool. When they are fed upon herbage grown in chalky districts, for example, the wool is apt to be coarse, whereas it becomes fine and silky on those reared upon a rich loamy soil. Sheep's wool varies from the long, straight, coaise hail' of certain varieties of the English sheep (Leicester, Lincolnshire, ttc), to the comparatively short, wavy, fine, soft wool of the Spanish Electoral sheep. Down to the end of the last centuiy the Spanish Merino sheep yielded the finest and best wool in the world. About that period this variety was imported into nearly every country in Europe, and by dint of careful selection and good breeding, the wool-gi'owers of Saxony and Silesia at length succeeded in producing wool which quite equalled that of the original Spanish race. Merino sheep have since been introduced into Australia, the Cape of Good Hope, New Zealand, kc. \ and these so- called Colonial wools, so much used and appreciated at the present time, all bear the Merino character derived from the original Spanish stock. According to the average length of the fibres com prising the locks of wool, or "staple," two principal classes of wool may be distinguished, namely, the long- stapled (18-23 centimetres) and the short-stapled wools {2-D—4: centimetres). In the process of manufacture into cloth, the former require to be combed, and serve for the production of so-called "worsted " goods, while the latter are carded, and used for "woollen" goods. It is well to add that this distinction between woi-sted and woollen goods refers rather to the operations of combing and carding than to the length of staple of the wool employed, since large quantities of worsted are made from short wool. The essential difference is really owing to a different arrangement of the fibres in the yarn. The 24 DYEING OF TEXTILE FABRICS. [Chap. ni. diameter of the ^ool fibre may vary from 0*007 to 0.5 millimetre. Very marked differences exist even in tlie wool of a single animal, according to the part of the body from which it is taken, and it is the duty of the v:ool-sorter to distinguish and separate the several qualities in each fleece. 24. The Physical Structure of the wool fibre is very characteristic, and enables it to be readily distin- guished from other textile fibres. Being a product of the epidermal layer of the skin, it is built up of an immense number of epi- thelial cells. When carefully examined under the microscope, a wool fibre is seen to consist of at least two parts, sometimes even of three. (1) The external cells appear as thin horny plates or scales of irregular shape ; they are arranged side by side and over- lapping each other, somewhat after the manner of roof-tiles (Fig. 8). The upper edges are more or less free, the lower are apparently imbedded in the interior of the fibre. In merino wool the scales appear fumiel-shaped, and fit into each other, each one entirely surrounding the fibre. In hair they are more deeply imbedded; they also lie flatter, and present but little free margin. This surface -character plays an impoi-tant part in causing the "felting" of wool in "milling," ttc. During this and similar operations, in which a large number of fibres are brought into close and promiscuous contact, each fibre naturally moves more readily in one dii-ection than in the other, and the opposing scales gi-adually become interlocked. (2) The cortical substance of the wool fibre Fig. 8. — Microscopical Appear ance of Wool Fibre. Chap. III.] PHYSICAL STRUCTURE OF WOOL. 25 constituting nearly, and sometimes entirely, the wliole internal portion of the fibre, is composed of narrow spindle-shaped cells, which have assumed a more or less ^ horny character. This structure, which gives the inner portion of a wool fibre a fibrous appearance when examined longitudinally un- der the microscope, is best seen after gently heating the fibre ^viih sulphuric acid. By means of a pair of dissecting needles it is then readily separated into its constituent cells. In Figure 9, b represents the microscopic appearance of the fibre after treatment with acid, and a shows some of the indi\ddual cells. It is an interesting fact that these disintegrated internal cells possess a greater attraction for colour- ing matter than the external scales, and^ the beneficial efiect of the acidity of the bath, required in many cases of mordanting and dyeing, may possibly be ascribed to the opening out of the epithelial scales and the exposure of the inner fibrous cells to the action of the liquid of the bath. This seems to explain also why "extracted" or "carbonised" wool dyes deeper shades and more rapidly than ordinary wool. (3) The central, or medullary, portion of the wool fibre, when present, is formed of several layers of rhombic or cubical cells, which appear as the marrow or pith of the fibre, and may traverse its whole length or appear only in parts. By boiling the fibre with alkali, It is often possible to squeeze out this medullary portion. In many classes of wool (merino, &c.) it seems to be entirely absent : indeed, its presence or absence depends D. H, HILL LfBRART North Carolina State College Fig. 9. —Cells of Wool Fibre under the Mi- croscope. 26 DYEIXG OF TEXTILE FABRICS. [Chap. HI. Upon a variety of factors, e.g., race, liealtli of individual, part of tlie body from wldcli the wool is taken, : tion, a wool fibre api)ears ^-~>^ J, -:: more or less round or Tig. 10.— Cross Sectio:- -::;>! -ol ^ *. n /^ • Wool Fibres. Figure 10 gives the cross sections, according to F. Bowman, of two typical wool fibres ; a shows the medullaiy, cortical, and external cells ; in b the medullaiy cells are al »sent. " Kemps " are certain wool fibres not possessing the normal structure of good wool ; under tlie microscope the epithelial scales are less distinct, or even invisible, and viewed by transmitted light, either the whole substance of the fibre seems more dense and sometimes even opaque, or the medullary portion only is opaque. They are deficient in tenacity, lusti'e, and felting power, and in their attraction for colouring matters. They may occur even in good qualities of wool, e.g., about the neck and leo^s of the animals, where the wool £:i'aduallv mercres into hair. In coarse wools they may be found in any part of the fleece. A merino wool fleece is made up of an immense number of small bundles or strands of wool fibres, which, in the best races of sheep, show a perfectly regular and Chap. TIL] FOREIGN WOOLS. 27 fine wavy character. The individual fibres are also more or less wavy, but not with the same degree of regularity as the strand of which they form a part. When the fibres adhere to each other, as in the strand, the regular wavy character is very marked. Besides sheep's wool, the hairy covering of other animals is used in the woollen industry. 25. Foreign Wools. — Alpaca, Vicuna, and Llama wool are obtained from different species of the genus Auchenia {A. alpaca, A. vicugnia, A. llama), which in- habit the mountains of Peru and Chile. Mohair is obtained from the Angora goat {Capra hircus angorensis) of Asia Minor. Cashmere consists of the soft under-wool of the Cash- mere goat {Capra hircus laniger) of Tibet. The soft under-wool of the camel, which it sheds each spring, is also used. Of all these, the alpaca and mohair are most largely employed. Certain of these foreign wools, more especially Yan Mohair, also Alpaca, Camel's haii^, Cashmere, and Persian wool, are apt to be dangerous to the health of the wool-sorter. They seem to contain the microscopic organism known as Bacillus anthracis, the same which excites splenic fever in cattle and horses. When taken into the bronchial tubes of man^ it induces a kind of blood-poisoning known as " wool-sorter's disease." The wool-sorting rooms ought, therefore, to be well ventilated, and the sorters should wear respirators during their work. 26. Physical Properties — Hygroscopicity. — The wool fibre is capable of absorbing a large amount of water with- out appearing damp, i.e., it is very hygroscojnc. Exposed to the air in warm, dry weather, it contains 8-12 per cent, moisture; but if kept for some time in a damp atmo- sphere, it may take up as much as 30-50 per cent. This moisture probably fills up the interstices between the cells of the fibre, which under ordinary circumstances contain air, but it no doubt also permeates the substance 28 DYEING OF TEXTILE FABRICS. [Cliap. HL of the cells themselves. It is noteworthy that damp wool is not so liable to mildew as the vegetable fibres are. The amonnt of moisture in "unwashed wool varies with the fatty matter it contains, the less fat the more moist^nej while in washed wool it depends npon the azrangemeait of the cells. The wool which has least te^sudty — Le., that in which the cells are more loosely axranged — possesses the greatest hygroscopicity. TMs hygroscopic character of wool renders it very de^iaiUe "tliat those trading with it should know exactly its condition in this respect at the time of buying and selling, hence, on the Continent, so-called '' Wool-conditioning" es- tablishments have been instituted in various centres of the woollen industry — e.g., Roubaix, Rheims, Paris — where the exact amount of moisture in any lot of wool may be officially determined. These establishments are arranged on the same principles as those for sUk- conditioning p. 61). As woo] is more sensitive to heat than silk, the drying of it is effected between 105°-110° C. The legal amount of moisture allowed on the Contiaent is 18-25 per cent. If wool fibre is steeped in warm water, it softens and swells up very considerably, and, Hke all homy sub- stances, becomes pJnstic, retaining any position which m.ay be forced upon it, if, while the mechanical strain is continued, the moisture is more or less evaporated. This hygroscopic and plastic nature of wool comes into play in the processes of " crabbing " and *' steam- ing " of unions, in the '■' boiling " and " finishing " (" hot- pressing") of woollen-cloth, and in the "stretching " of yam. Elasticity. — Closely connected with the hygroscopic nature of wool is its elasticity, which it possesses in a high degree, not merely because of the wavy character of the fibre, but also on account of its sub- stance and structure. One important manifestation of its elasticity is shown if a drj^ wool-fibre is excessively stretched; when the ends are released, or rupture takes place, not only does the fibre or do the separated parts Cliap. in.J PHYSICAL PROPERTIES OF WOOL. 29 rebound to the original position, but an additional shrinking and curling up of the ends are exhibited. If a single ^yool fibre is softened by heat and moisture, then stretched and dried in this condition, it is found to have lost this curling property, but it reappears whenever the stretched fibre is again softened, and allowed to dry in an unfettered condition. In conjunction with pressure, friction, and tempera- ture, many of the above-mentioned physical features — e.g., the scaly surface of the fibre, its waviness, and its hygroscopic, elastic, and plastic nature — play a most im- portant part in the processes of "felting" and "milling " woollen cloth. The lustre of wool varies very considerably. Straight, smooth, stiff wool has more lustre than the curly merino wool. The difi'erences exhibited depend partly upon the internal structure, but chiefly upon the varying arrange- ment and transparency of the scales on the surface of the fibre ; the flatter these are and the more they lie in one plane, the greater will be the lustre. Such wools as possess a silky lustre in a high degree — e.g., Lincoln and Leicester wools, &c. — are classed as lustre wools, as distin- guished from non-lustre wools — e.g., Merino, Colonial, ifcc. Wool with a glassy lustre, e.g., bristles, &c., is harder and more horny than non-lustre wool ; the surface is smoother, the scales are less distinct, and wools of this kind do not dye so readily. The best kind of wool is colourless, but lower qualities are often yellowish, and sometimes variously coloured— £•.^'7. ^ black, brown, red, kc. This coloration is caused by the presence of an organic pigment in the cortical portion of the fibre, either as a granular pigment situated between the cells, or as a colouring matter difliised throughout the cell substance. Generally, both forms are present, but in brown and black wool the granular pigment pre- dominates, while in red and yellow wools the diffused colouring matter is more prominent. These natural pig- ments are not so fast to light as is generally supposed, a 30 DYEING OP TEXTILE FABRICS. [Chap. III. fact which is already revealed by the bleached appearance of the exposed portions of the fleece. The worth of any quality of wool is determined by carefully observing a number of its physical pro- perties — e.g., softness, fineness, length of staple, waviness, lustre, strength, elasticity, flexibility, colour_, and the facility with which it can be dyed. Fleece wool, as shorn from the living animal, is superior in quality to ^^ dead wool,^^ i.e., wool which has been removed from the skin after death, if lime has been used in the process, but if it be removed from the skins by cutting, the wool is practically equivalent to " fleece wool ; " indeed, it is said to felt better than the latter. Individual dead fibres occur occasionally in fleece wool ; they have been forced out by the roots previous to the time of shearing, and constitute the so-called ^' overgrown " wool. This class of wool is comparatively harsh and weak, and is said not to dye so readily as other kinds. This is the case also with the wool of an animal which has died of some distemper. 27. Chemical Composition. — With regard to the chemical composition of wool, a distinction must be made between the fibre 'proper and the foreign 'matters encrusting it. The latter, while consisting partly of mechanically adhering impurities derived from without, are mainly secreted by the animal, and constitute the so-called Yolk (Fr. Suint). Wool fibre which has been entirely cleansed and freed from these foreign matters possesses a chemical composition very similar to that of horn and feathers, and consists of what is termed Keratin (horn-substance). Its elementary composition varies somewhat in difi'erent qualities of wool, but the following analysis of German wool may be taken as representative : — Carbon 49-25 per cent. Hydi'ogen Oxygen Kitrogen Svilpliur . 7-57 23-66 15-86 3-66 100-00 Chap. III.] CHEMICAL COMPOSITION OF WOOL. 31 The question as to whether the sul^Dhur is an essential constituent or not has been much discussed. It is removed to a gi^eater or less degree by most solvents, hence it is difficult to obtain constant analytical results. Its amount has been found to vary in different wools from 0-8 to 3-8 per cent. Its constant occurrence, and that in comparatively large proportion, precludes the idea that it is merely an accidental constituent, and it has liitherto been found impossible to deprive wool entirely of its sulphur, ^Yithout, at the same time^ modifying somewhat its structure and in large measure destroying its tenacity. This presence of sulphur in wool is attended with some practical disadvantages. The wool is apt to con- tract dark-coloured stains under certain conditions, and on that account its contact with such metallic surfaces as those of lead, copper, and tin should be avoided during processes of scouring or dyeing. In mordanting with stannous chloride and cream of tartar, especially if an excess of these ingredients be used^ the wool is frequently stained, by reason of the formation of stannous sulphide. A boiling solution of plumbite of soda at once blackens wool, and may thus serve to distinguish it fi'om silk or cotton. For practical purposes, much of the sulphur may be removed by steeping the wool in cold weak alkaline solutions— e.^., milk of lime, — then washing it in water, in weak hydrochloric acid, and again with water, repeating the operations several times. The amount of mineral matter in wool free from yolk varies from 0-08-0-37 per cent. It consists mainly of phosphates and silicates of lime, potash, iron, "^and magnesia. Action of various Agencies on Wool. 28. Action of Heat— If heated to 130° C, wool begins to decompose and give off ammonia; at 140-150° C. vapour containing sulphur is disengaged. When wool fibre is inserted in flame it burns with 32 DYEING OP TEXTILE F.ABRICS, [Ctap. in. some difficulty, and emits a disagreeable odour of bm-nt feathers. It lias the appearance of fusing, a bead of porous carbon being fonned at the end of the fibre. Submitted to dry distillation, it gives off products containing much ammonium carbonate, which may be readily detected by its smell or by its coloumig red litmus-paper blue. These reactions serve to distinguish wool from all vegetable fibres. A cold ammoniacal solution of cupric hydrate has no action upon wool, but if it is used hot the wool is dis- solved. 29. Action of Acids. — Dilute solutions of hydro- chloric and sulplturic acids ha^e little influence upon wool, whether applied hot or cold. fiui;her than opening out the scales and making the fibre feel somewhat rougher, but if used too concentrated, the fibre is soon disintegrated; in any case their destructive action is by no means so ener2:etic on wool as on cotton. This fact is made use of to separate cotton from wool in the* process of " ex- tracting '' or '' carbonising " rags containing both fibres. The rags are steeped in dilute sulphuric acid, and after removing the excess of liquid, are dried in a stove at about 110° C. The disor2:anised cotton can then be beaten out as dust, while the wool remains compara- tively little injured. Another method is to submit the rags for a few hours to heated hydrochloric acid gas. The above mineral acids are frequently added to the dye-bath in wool-dyeing. Nitric acid acts like the acids just mentioned, but it also gi\'es a yellow colour to the wool, owing to the production of so-called xanthoproteic acid. Because of the compara- tively light yello^Tsh colour thus imparted, boiling di- lute nitric acid is frequently used as a " stripping " agent for wool, i.e., to destroy the colour in wool already dyed, for the purpose of re-dyeing (job-dyeing, rectifying mis- takes, (tc). Care must always be taken not to have the acid too stroDg (about 3^-4:° Tw. — Sp. Gr. 1"02), and not to prolong the process beyond three or four minutes. Sulphur dioxide (sulphurous acid gas) removes the Chap. III.l ACTION OF ALKALIS ON WOOL. 33 natural yellow tint of ordinary wool, and is the best bleaching agent employed for this fibre. It is important to remember that the gas is very persistently retained by the fibre, and should always be removed from bleached ■wool previous to dyeing light colours. This is effected by steeping the wool in very dilute solutions of carbonate of soda or bleaching-powder, and washing well. When the first reagent is employed, the acid is merely neutral- ised, but with the second the sulphurous acid is oxidised to sulphuric acid. Should this precaution be neglected, the wool will not dye properly, or, when dyed, it will be liable to become decolorised ao^ain throucrh the reducing action of the sulphur dioxide retained by the fibre. 30. Action of Alkalis. — Alkaline solutions have a very sensible influence on wool, but the effects differ considerably according to the nature of the alkali, the concentration and temperature of the solution, and the duration of contact. Caustic alkalis (KHO, NaHO) act injuriously on wool under all circumstances. Even when they are applied as cold and weak solutions, their destructive action is sufficient to warrant their complete rejection as " scouring " agents. When they are applied hot, even though but little concentrated, the wool is gradually dissolved, producing a soapy liquid from which it may be precipitated, on the addition of acid, as a white amorphous mass. This fact of the solubility of wool in hot caustic alkalis is utilised for the purpose of recovering indigo from vat-dyed woollen rags, this colouring matter being insoluble therein. Solutions of alkaline carbonates and of soap have little or no injurious action on wool, if they are not too concentrated, and the temperature is not higher than 50° C. Soap and carbonate of ammonia have the least injurious action, while the carbonates of potash and soda impart to the wool a yellow tint, and leave it with a slightly harsher and less elastic feeL 34 DYEING OF TEXTILE FABRICS. [Chap. ILL This marked difference of action between the caustic and carbonated alkalis makes it an all- important matter for every wool-scourer to know the exact nature of the agents he uses : soaps should be fi'ee from excess of alkali, " soda ash '' should contain no caustic soda, kc. Calcium hydrate {lim^e) acts inj uiiously, like the caustic alkalis, but in a less degree. It eliminates the sulphur from the wool, but thereby renders the fibre brittle and impairs its milling properties. 31. Chlorine and Hypochlorites act injuriously on wool, and can therefore never be applied to it as bleach- ing agents. A hot or boiling solution of chloride of lime entirely destroys the fibre, with evolution of nitrogen gas ; if, however, wool be submitted to a very slight action of chlorine or hypochlorous acid, it assumes a yellowish tint, and acquires at the same time an increased affinity for many colouring matters. This effect is possibly due to an oxidation of the fibre, and not merely to a roughening of its surface. Practical use is made of it by the printer of Muslin Delaine (mixed fabrics of cotton and wool) and occasionally by the woollen dyer. 32, Action of Metallic Salts. — In common with all fibres of animal ori^'in, wool has the property of readily dissodatiDg certain metallic salts when in contact with their solutions, especially if the latter are heated. When, for example, wool is boiled with solutions of the sulphates, chlorides, or nitrates of aluminium, tin, copper, iron, chromium, erations of dyeicg ; hence the neoe^ity of stringing, stretching, and lustreing, above al- luded to, in order to prevent or counteract the contraction. The tenacity and elasticity of raw- silk reside largely in its external coating of silk-glue. By boiling-off with soap, it loses 30 j:>er cent, of its tenacity, and 45 per cent, of its elasticity. Cliip. IV.] CONDITIONING. uV These properties vary in weighted silk, according to the nature of the weighting. If the fibre is simply coated with such substances as gelatin, albumen, starch, ttc, the tenacity will be as a rule increased, but if the weighting materials employed penetrate the substance of the fibre, and cause it to swell in a greater or less degree, the natural properties of the silk will be modified accordingly. Some agents, like the simple colouring matters, have no appreciable influence, while others, e.g.j astringents and metallic salts, when used in large excess, gi-adually destroy the valuable properties of silk entirely. {See Black Silk Dyeing, p. 332.) If silk is heated to 110^ C. it loses all its natural moisture, but remains otherwise quite unchanged. Exposed to 170^ C, and higher, it soon begins to decompose and carbonise. If a silk fibre be inserted in a flame it has the appearance of fusing like wool, but it does not give ofl" quite such a disagreeable odour. Silk is a very bad conductor of electricity, and since it readily becomes electric by friction, this condition, once acquired, is very persistent, and is apt to become a source of trouble during the mechanical operations involved in manufacturing. The most effective mode of overcoming the difficulty is to keep the atmosphere of the work- rooms in a suitable state of humidity. In its boiled-off" and pure state silk resists ordinary decay most thoroughly, and it is rarely attacked by insects. 47. Silk Conditioning'. — If raw sUk be kept in a humid atmosphere it is capable of absorbing thirty per cent, of its weio:ht of moisture without this beins: at all perceptible. This circumstance, coupled with the high price of raw silk, makes it of very gi-eat importance to those who trade with it to know exactly what weight of normal silk there is in any given lot which may be the subject of commercial dealings. To ascer- tain this information there have been established, in about thirty-seven centres of the silk industry, so-called Fig. 22.— Conditioning Apparatus. Chap. IV.] CONDITIONING. Gl conditioning establishments, e.g., in Lyons, Crefeld, Zurich, Bale, Turin, Milan, Vienna, Paris, London, &c., &c. Fig. 22 shows the external appearance of the essen- tial apparatus of such an establish- ment, namely, the desiccator. It consists of an enamelled cylin- drical hot - air chamber. One arm of a fine balance sustains a crown of hooks, to which are at- tached the skeins of silk to be dried. The sus- pending wire passes through a small opening in the cover of the cylinder. The other arm of the balance carries the ordinary pan for weights. Fig. 23 gives a vertical section of the chamber. Hot air at 110° C. enters by the tube A from a stove situ- ated in a cellar below, passes into the space B, and thence by thirty-two vertical tubes, t, placed between the two concentric cylinders c and D, it enters the upper por- tion of the inner cylinder d. The hot air descends, dries the silk, and escapes by the tubes e, which com. manicate with the exit flue. The apparatus is provided Fig. 23. — Section of Conditioning Chamber. 62 DYEING OF TEXTILE FABRICS. [Chap. IV. vrith a valve v, actuated by the lever k (Fig. 22) for resnilating: or shutting off the current of hot air. The air -which passes outside the brickwork of the stove, and is thus heated only to a moderate degree, passes upwards between the cylinders c and D into the space r; by means of the button l, which actuates a slide-valve, its entrance into the central chamber can be regulated. By means, therefore, of the le^•er K and the button L, the supply of hot and cold air into the central chamber can be regulated to a nicety, and the temperature of the mix- ture is ascertained by the thermometer T, The button s actuates the valve M, which cuts off communication with the exit flue and stops the current of air during a final weighing operation. Several hanks of silk are taken from the bale to be tested and diNided into three lots, in order to be able to make two parallel determinations, and a third if necessary. TJie weight is first rapidly taken, under ordinary circum- stances, on a fine balance ; the hanks are then suspended in the desiccator and counterpoised, and the hot air current is allowed to circulate till no further loss of weight takes place. One opei'ation may la.st from a half to three-quarters of an hour. The average loss of weight usually met with is about 12 per cent. Absolutely dry silk is not reckoned as the standard article, but such as contains about 90 per cent. dry silk and 10 per cent, moisture. The legal weight is really obtained by adding 11 per cent, to the dry weight, 48. Chemical Composition. — The silk fibre has been the subject of numerous chemical researches, the general result of which may be summed up by saying that it is composed essentially of two distinct parts : first, that constituting the central portion of the fibre, and secondly, a coating, or envelope, consisting apparently of a mix- ture of substances mostly removable by hot water, or, at any rate, by solvents which have little or no action on the central portion- Chap. IV.] ANALYSIS OF SILK. 63 Fibroin. — In oi'der to determine the character and amount of these several substances, Mulder submitted Taw Italian silk to the successive action of boiling water, alcohol, ether, and hot acetic acid, and in this way- obtained in a comparatively pure state the central silk substance, to which he assigned the name Fibroin. The following numbers give the results of his analysis : — Yellow White Italian silk. Levant silk. Silk fibre (fibrom) 53-35 64-05 Matters soluble in water 28-86 28-10 ,, „ alcohol 1-48 1-30 „ „ ether 0-01 005 „ „ acetic acid 16-30 16-50 100-00 100-00 By a further examination of the substances which each solvent had extracted, he arrived at the following more detailed analysis : — Yellow White Italian silk. Levant silk. Fibrom ..... 53-37 54-04 Gelatra 20-66 19-08 Albumen 24-43 25-47 Wax 1-39 Ml Colouring matter . 0-05 0-00 Resinous and fatty matter 0-10 0-30 100-00 100-00 Mulder explains that on evaporating the aqueous solution to dryness, the residue would not entirely re- dissolve in water. This insoluble portion, therefore, and that which is dissolved by acetic acid, has been reckoned as albumen. Exception has been taken by Bolley with regard to the presence of this albumen, for if it is borne in mind that the temperature employed in killing the cocoons, and that of the water used during the reeling process, is such as to coagulate any albumen which might possibly be present, it is highly improbable that raw silk would contain any soluble albumen. 64 DYEIXG OF TEXTILE FABRICS. [Cliap. IVT. Fui-ther, it has been shown that living cocoons, which have not therefore been submitted to any steaming process, but have simply been opened and heated with tepid water, contain no albumen. Fibroin itself, too, is known to be somewhat soluble in strong acetic acid, so tliat it may, on the whole, be concluded, that what Mulder found to be soluble in acetic acid was not albumen, but altered fibroin, and that the percentage of this latter sub- stance in silk which he gives, is too low. By heating raw silk for several hours with water at 133^ C, a residue of fibroin is obtained which, after the removal of fattv matter bv ether, and coloui'ino^ matter by alcohol, represents 66 per cent, of the weight of the silk. Even this figure may possibly be too low, since the usual loss in practice during the operation of " boil- ing-off " is 25-30 per cent. Tlie percentage composition of pure Fibroin has been variously stated, probably owing to the different hygro- metric state of the fibres examined. Cramer gives the formula as C^jH.^oX-Og. Sericin. — That portion of silk which is soluble in waiTQ water can be precipitated from its solution by lead acetate. By submitting this precipitate to a somewhat t-edious series of operations — such as washing with water, suspending in water and decomposing with sulphui-etted hydi'ogen, filtering, and evaporating the filtered solution, precipitating and extracting with alcohol, then with ether — it is possible to obtain the essential constituent of the external envelope of the silk fibre as a colourless, odourless, tasteless powder. It swells up in cold water, and is somewhat more soluble in hot water than gelatin. A six per cent, solution of it gelatinises on cooling, and its solutions are precipitated by alcohol, tannic acid, and metallic salt solutions. ^ytogether. its physical and chemical properties are very similar to those of glue and gelatin ; hence Sei'iciri is often called sUhglu€j sometimes also sUk-gum. Its chemical composition is represented by the formula — CijHj^N^Og. Chap. IV.] ACTION OF WATER ON SILK. 65 It is distinct from ordinary glue, however, according to some observers, since when boiled with dilute mineral acids it yields different products. If the formulae given for fibroin and sericin be com- pared, a relationship is apparent which may be expressed by the following equation : C15H23X5O6 + + H20=Ci5H,,N,08 Fibroin. Sericiu. Although these formulae can only be considered as representing approximately the percentage composition of these two bodies, the above comparison has been taken by some as an indication that originally, i.e., at the moment of secretion, the silk fibre is probably a homogeneous substance, which, by the action of the air and moisture, rapidly becomes altered superficially. This view is supported by the observation that if moist fibroin be left exposed to the air for a lengthened period it becomes partially soluble in water. Bolley and Rosa have found also that the silk-bags taken from living worms are composed almost entirely of fibroin, since only 1*7 per cent, is soluble in boiling water, and the ele- mentary analysis is consistent with tlie formula of fibroin. The physiological studies of Duseigneur, and especially his examination of the transverse section of the silk-bag, already alluded to, appear to contradict this view. hijluence of lieagents on Silk. In contact with various liquids silk not only absorbs them rapidly, on account of its great porosity, but some- times retains them with extreme tenacity ; this is the case, e.g. J with alcohol and acetic acid. For the same reason it has great aptitude for fixing mordants and colouring matters. 49. Action of Water. — Prolonoed boilino- vdth water removes from raw silk its silk-glue, but it has little eflfect upon the fatty, waxy, and colouring m.attei-s present. The tenacity of the fibre is reduced even 66 DYEING OF TEXTILE FABRICS. [Chap. IV. more tlian by the ordinary methods of ungumming witli soap solutions. A similar solvent action is exercised by all liquids ; for this reason it is not customary to Diordant silk with hot solutions, and the dyeing is conducted at a temperature as low as circumstances will permit. 50. Action of Acids. — Speaking generally, concen- trated mineral acids rapidly destroy silk, but if sufficiently diluted their action is insensible. Warm dilute acids, however, dissolve the sericin of raw silk, and hence these may be used in ungumming (soupling). Concentrated suljjhuric acid dissolves silk, giving a viscous brown liquid ; on diluting the latter with water a clear solution is obtained, from which the fibroin is precij)itated on the addition of tannic acid. Concentrated nitric acid also rapidly destroys silk ; but if diluted, the latter is only slightly attacked and coloured yellow, in consequence of the formation ol xanthoproteic acid. This reaction is made use of in distinguishing silk from vegetable fibres. Formerlv it was also utilised in dyeing; a method, however, not to be commended, since the colour is produced at the expense of the silk itself, which must inevitably be weakened by the process. Hydrochloric acid, if applied in the gaseous state, destroys the fibre without liquefying it, but a concen- trated aqueous solution readily dissolves it. Hydrochloric acid 38° Tw. (Sp. Gr. 1-19) when applied cold, dissolves an equal weight of silk without even then being saturated. Dilute hydrochloric acid has no sensible action, except upon the sericin of raw silk, which it more or less removes. Phosphoric and arsenic acids in dilute (5 per cent.) aqueous solution act like other weak acids in removing the sericin from raw silk, and have been proposed as luigumming agents instead of soap, but they are not used in practice. Fermangariic acid, either in the free state or in combination with potassium, acts energetically on silk ; Chap. IV.] ACTION OF ACIDS AND ALKALIS ON SILK. 67 it oxidises and colours the fibre brown by deposition of hydrated manganic oxide. If this be removed by immersion in a solution of sulphurous acid, the silk is left in a remarkably pure white condition. Although recommended on this account for bleaching silk, it is not altogether suitable, since the silk thus bleached always has a tendency to become yellowish under the influence of alkalis. Sulphurous acid is used in bleaching silk. Chromic acid and chromates, like permanganic acid, oxidise silk, leaving the fibre of a pale olive tint. The action of organic acids on silk has been little studied ; it varies, no doubt considerably, according to their concentration, temperature, &c. Hot dilute organic acids remove the sericin from raw-silk but do not afiect the fibroin much. Cold glacial acetic acid removes the colouring matter from yellow raw-silk without dissolving the sericin. Silk is entirely dissolved when heated under pressure with acetic acid. 51. Action of Alkalis. — Concentrated solutions of caustic soda and potash rapidly dissolve raw-silk, espe- cially if applied warm. Caustic alkalis, sufficiently diluted so as not to act ap- preciably upon the fibroin, will dissolve ofi" the sericin, and have been tried as ungumming agents. For ordinary use, however, they must be avoided, since the silk is always left impaired in whiteness and brilliancy. Pure ammonia solution, even if used warm, has no sensible action on boiled-off silk, but if it is at all impure the silk becomes dull and dirty from absorbed tarry matter. Ammonia seems to favour the absorption by silk of salts of calcium, magnesium, &c. Alkaline carbonates act like the caustic alkalis, but in a less energetic manner, and they are not employed as ungumming agents. Of all alkaline solutions, those of soap have the least injurious efiect. When used hot, they readily remove the sericin from raw-silk, and leave 68 DYEING OF TEXTILE FABRICS. [Chap. IV. the fibroin lustrous and brilliant; hence soap is })ar excellence the ungummiug agent employed. Borax acts somewhat like soap, but cannot replace it in practice. If raw silk be steeped for twenty-four hours in clear, cold lime-water, it swells up considerably, the lime seeming to have a strong softening action on the sericin ; when this is removed by dilute acid and a subsequent soap bath, the fibroin seems not to have suffered otherwise than by the loss of its natural brilliancy. Prolonged contact, however, with lime-water renders silk brittle and disorganised. Chlorine and hifpochlorites attack and destroy silk rapidly, and cannot be used as bleaching agents. Applied in weak solutions, with subsequent exposure of the fibre to the air, they cause the silk to have an in- creased attraction for certain colouring matters. 52. Action of Metallic Salts. — If silk is steeped in cold solutions of several metallic salts, e.g., of lead, tin, copper, iron, aluminium, etc., it absorbs and even partly decomposes them, so that less soluble basic salts remain in union with the fibre. The methods of mordanting silk with aluminium, tin, and iron salts de- pend upon this fact. Sometimes, as in the case of ferric and stannic salts, the quantity of basic salt which may be l)recipitated on the fibre is sufficient to serve as weighting material. Concentrated zinc chloride, 138° Tw. (Sp. Gr. 1-69), made neutral or basic by boiling with excess of zinc oxide, dissolves silk, slowly if cold, but very rapidly if heated, to a thick gummy liquid. This reagent may serve to separate or distinguish silk from wool and the vegetable fibres, since these are not aff'ected by it. If water be added to the zinc chloride solution of silk, the latter is thrown down as a flocculent precipitate. If this is washed free from zinc salt and dissolved in ammonia, it is said that the solution mav serve to cover cotton and other ft/ viigetable fibres ^vith a coating of silk substance. Dried Chap. IV.] SOLVENTS FOR SILK. 69 at 110° — 115*^ C, the precipitate acquires a vitreous aspect, and is no longer soluble in ammonia. An ammoniacal solution of cupric hydrate dissolves silk, the solution not being precipitated by neutral salts, sugar, or gum, as is the case with the analogous solution of cotton. An ammoniacal solution of nickel hydrate also dissolves silk. A most excellent solvent for silk is an alkaline solution of copper and glycerine, made up as follows : dissolve 16 grams copper sulphate in 140 — 160 c.c. distilled water, and add 8 — 10 grams pure glycerine (Sp. Gr. 1-24); a solution of caustic soda is dropped gradually into the mixture till the precipitate at first formed just re-dissolves ; excess of NaOH must be avoided. This solution does not dissolve either wool or the vegetable fibres, and may serve therefore as a distinguishing test. 53. Action of Colouring Matters. — Generally speaking, silk has a very great affinity for the mono- genetic colouring matters. It can be dyed direct with the aniline colours, for example, with the greatest facility. It has, however, little attraction for mineral colouring matters. An examination of sections of dyed silk reveals the fact that the colouring matter (or the mordant) penetrates the substance of the silk fibre to a greater or less degree, according to the solubility of the colouring matter, the duration of the dyeing process, and the temperature employed. If the silk is dyed only for a short time, a section of the fibre shows an external concentric zone of colour, while if the dyeing operation is continued suffi- ciently long, it is coloured right to the centre. If a mixture of two colouring matters be applied, either simultaneously or successively, both are absorbed, the more soluble, or that which has been allowed to act longest, penetrating the fibre most deeply. Externally a mixed effect is produced in this case, but a section of the fibre reveals in most cases two concentric zones of colour. Silk thoroughly mordanted with a ferric salt presents in section a uniform 70 DYEING OF TEXTILE FABRICS. lCha]\ IV. yellow tint ; if dyed subsequently in an acidified solution of potassium ferrocyanide, the ferric oxide deposited in the silk gives place to Prussian blue, at. first in the outer portions only, but by degrees even in the centre, especially if the temperature of the bath be raised. A similar efiect is produced if a bath of tannin be sub- stituted for that of potassium ferrocyanide. It is indeed difficult to say what number of substances might be successively absorbed by the silk, and penetrate it either by juxtaposition or by reacting upon each other. The action of colouring matters on raw silk is similar ; but in many cases, e.g., in the black dyeing of souples, the colouring matter is situated principally in the external silk-glue, which, becoming brittle through the large amount of foreign matter it then contains, breaks up and assumes the form of microscopic beads. 71 OPEEATIONS PEELIMINAEY TO DYEINa. CHAPTER V. COTTON BLEACHING. 54. Object of Bleaching. — As already noticed in treat- irg of the cotton fibre, raw cotton is contaminated with sev^eral natural impurities, and although these are com- paratively small in amount, they impair the brilliancy of the white belonging to pure cellulose. Hence cotton yarn as it leaves the spinner has invariably a soiled or greyish colour. When such yarn is woven it is still further contaminated with all the substances (amounting some- times to 30 per cent.) which are introduced during the sizing of the warps, e.g., china clay, grease, &c. Bleaching consists in the complete decolorising or removal of all these natural and artificial impurities, either for the purpose of selling the goods in the white state, or in order to make them suitable for being dyed light, delicate, and brilliant colours. 55. Bleaching of Unspun Cotton (Cotton-wool). — Although cotton-wool is now largely dyed, it is seldom or never bleached in this form, because it would become more or less matted together. As a rule, the only treat- ment previous to dyeing which it receives is that of boiling with water until thoroughly wetted. It would no doubt be better to boil with a dilute solution of caustic or carbonated alkali, and afterwards to wash well with water — e.g., in machines similar to those used in loose-wool 72 DYEING OF TEXTILE FABRICS. [Cha^. V. scouiTiig (see p. 100) — since by this means the natural waxy matt€i*s, (tc, would be more thoroughly removed. More complete bleaching would be tedious, and is pro- bably unnecessary. 56. Bleaching of Cotton Yarn. — When cotton yarn has to be dyed Vjlack or dark coloui^s, it is as a rule not bleached, but merely boiled with water till thoroughly softened and wetted. For light colours the dyer frequently effects a mpid, though perhaps more or less incomplete bleaching, by passing the wetted yarn (e.g.^ waii^:»s) throuah a boiling weak solution of soda-ash, then steeping it for a few hours in a cold weak solution of chloride of lime or hypochlorite of soda. It is then washed in water, steeped in dilute hydrochloric acid, and finally well washed. A more complete and thorough bleaching is that efiected by the operations now to be briefly described. ""Warps'" are loosely plaited by hand or machine, in order to reduce their length. If the yarn is in hanks it is either retained in that form, or linked together to form a chain, the latter being the better and more econo- mical method. 1. Ley boil. — For 1,500 kilos, yarn, boil six hours with 2,000 litres water and 300 litres caustic soda 32- Tw. (Sp. Gr. 1'16) ; steep in water for forty-five minutes and wash. 2. Cliemiching. — Steep the yam for two houi^ under sieve in a solution of bleaching powder 2^ Tw. (Sp. Gr. I'Ol), then wash for half an hour under sieve. 3. Souring. — Steep the yam for half an hour under sieve in dilute sulphuric acid P Tw. (Sp. Gr. 1-005), then wash for half an hour under sieve and afterwards through washing machine. If the yarn is intended to remain white and not to be dyed, it is run through a so-called "dumping" macliine with hot soap solution and blue (ultramarine, 4rc.), then hydro-extracted and dried. Chap, v.] COTTON YARN BLEACHING. 73 AVhen bleaching cotton thread, owing to its closer texture, the first three operations are repeated. The boiling (also called "bowking" or "bucking") with caustic soda solution takes place in large iron boilers or " kiers." These are either open or provided ^vith a lid capable of being screwed down, in order to be able to boil with a slight pressure of steam. The general appearance and internal arrangement of a low- pressure bleaching kier is well shown in Fig. 88. The usual order of procedure is first to fill the kier with the yarn, and after blowing steam through for an hour or so, to run in the soda solution and boil for ten to twelve hours. The mode of circulation of the liquid through the goods is described on page 434. The operations of chemicking, souring and washing under sieve, are carried out by means of the arrangement shown in Fig. 24. It consists of a stone tank e, with a false bottom f, and a valve G, communicating with the cistern d below ; b is the shaft which works the pump c ; f' is a movable perforated drainer or sieve covering the whole surface of the tank e ; A is a winch for drawing the chain of yarn into the tank. Supposing the tank to be packed with yarn, the pump is set in motion, the liquid in D is thus raised to the sieve f', whence it showers down on the yarn below. It filters, more or less rapidly, through the yarn and collects again in the tank D to circulate as before. Complete separate arrangements of this kind are required both for chemicking and for souring, but the washing under sieve is performed in either set of tanks as required, it being only necessary to stop the pump, close the valve g, and allow water to flow from a tap placed over the sieve, and to escape at the bottom of the tank E by a separate plug- hole into the nearest drain. The final washing after souring is best given by means of a machine similar to that represented in Fig. 62. The " dumping " machine referred to is essentially the same in gonstruction as the final washing machine, 74 DYEING OF TEXTILE FABEICS. [Chap Pig. 24, — Apparatus for Chemickiiig, Souring, and Wasliing. the main difference being that the square beater is re- placed by a round roller, and that the upper squeezing Char, v.] CALICO BLEACHING. 75 roller is covered with cotton rope and rests loosely with its own weight on the lower one. As the cotton yarn, soaked with soap solution and blue, passes rapidly between the squeezing rollers, the irregularities produced by the plaiting or linking impart a constant jumping motion to the upper roller, and the liquid is eftectually beaten and pressed into the heart of the yarn, thus enhancing considerably the purity of the white. When the yarn is bleached as separate hanks and not in the chain, the washing is effected by one or other of the machines illustrated in Figs. 54, 55, 56, and the " dumping " is done in the " stocks " (see Fig. 52). 57. Bleaching of Cotton Cloth or Calico. — The mode of bleaching is varied according to the immediate object for which the bleached calico is intended ; thus, one may distinguish between the Madder-bleachy the Turkey-red- hleach, and the Market-hleach. Madder-bleach. — This, the most thorough kind of calico-bleaching, was originally so-called because it was found specially requisite for those goods which had to be printed and subsequently dyed with madder. Its object is to effect the most complete removal possible of every impurity which can attract colouring matter in the dye-bath, so that the printed pattern may ultimately stand out in clear and bold relief on a white background of unstained purity. Although the madder-bleach is in general use among calico-printers, it may be also adopted by dyers whenever the calico is to be dyed subsequently in light and delicate colours, or if absolute freedom is desired from any impurity which resists the fixing of the colouring matter to be applied. Stamping and Stitching. — For the purpose of subse- quent recognition, the ends of each piece are marked with letters and figures, by stamping them with gas-tar or other substance capable of resisting the bleaching pro- cess. The pieces are then stitched together, end to end, by machinery. Singeing, — This operation consists in burning off the 76 DYEING OF TEXTILE FABRICS. [Chap. V. nap or loose liLres wliich project from the surface of the cloth, since these interfere with the production of fine impressions during the printing process. It is performed by rapidly passing the cloth in the open width over red- hot plates or cylinders, or over a row of gas flames. Fig. 25 shows a usual arrangement of the plate-singe- ing machine. By means of the rollers R, driven by a small engine, the piece g is rapidly drawn across the two Fig. 25. — Plate-singeing Machine. red-hot copper plates p p, against which it is depressed by the four bars of the iron frame d^ capable of being raised or lowered by the chain c. Immediately on leaving the plates, the piece passes between two perforated steam pipes K K, and through the water trough b, so that all adhering sparks may ]ye at once extinguished; h is a hood for leading away the products of combustion. The two plates are heated by means of the furnace below. The great difficulty in plate-singeing is to keep the plates at a uniform strong red heat, owing to the rapid cooliQg action of the passing pieces ; hence the "revoh'ing singeing roller '" is a decided improvement on the plate. In this arrangement the flames from the furnace pass through a copper cylinder which slowly revolves, so that a Ctap. v.] CALICO BLEACHING. 77 fresh red-hot surface is continually presented to the piece, and a regular even singe is thus obtained. As a rule, hot-plate or cylinder singeing is preferred for thick heavy cloth, but for light, thin cloth — e.g.^ muslins, &c. — singeing by gas is generally adopted. The gas-singeing machine consists essentially of one or more rows of gas jets, across which the cloth is rapidly drawn. The gas is mixed with air just before being burnt, so that an extended line of the well-known smoke- less Bunsen flame is presented across the full width of the piece ; by means of levers the gas jets may be placed at any suitable distance from the cloth, or in case of acci- dent they can be entirely withdra^vTi from it. The preliminary work of stamping, stitching, and singeing is succeeded by the bleaching operations proper, which, for 24,000 kilos, cloth and with low pressure kiers, may be summarised as follows : — 1. Wash after singeiDg-. 2. Lime-boil : 1,000 kilos, lime, boil 12 hours: wash. 3. Lime -sour: hydrochloric acid, 2' Tw. (Sp. Gr. I'Ol); wash. 4. Ley-boils : 1st, 340 kilos, soda ash, boil 3 hours. 2nd, 860 kilos, soda ash, 380 kilos, resin, 190 kilos, solid caustic soda, boil 12 hours. 3rd, 380 kilos, soda ash, boU 3 hours ; wash. 5. Chemicking : bleaching powder solution, i^ — i^ Tw. (Sp. Gr. 1-00125— 1-0025) wash. 6. White-sour: hydrochloric acid, 2' Tw. (Sp. Gr. I'Ol), pile 1 — 3 hours. 7. Wash, squeeze and dry. 1. Wash after Singeing, — The object of this operation is to wet out the cloth and make it more absorbent, also to remove some of the weaver's dressing. This was for- merly eflected by simply steeping the cloth in water for several days until, by the fermentation induced, the starchy matters were rendered more or less soluble. At present, printers' calicoes are not, as a rule, heavily sized, and a simple wash in the machine represented in Fig. 60 is sufficient. The pieces are drawn direct from the adjacent 78 DYEING OF TEXTILE FABRICS. [Chap. V. singeing house, guided by means of white glazed earthen- ware lings (•' pot-eves "'), through the washing machine ; they are at once plaited or folded down on the floor and there allowed to lie "in pile *' for some hours to soften. By this fii-st opei'ation, fi*equentlY called "gi-ey- washing,*' the pieceS; hitherto in the open width, assume the chain form, which they retain throughout the whole of the succeeding operations. 2. LimeioU ("Lime-bowk"). — The pieces are now run through milk of lime, a portion of which they absorb. They are at once drawn by overhead winches into the kiers and there plaited down and well packed by tramp- ling under foot. Fig. 26 shows the arrangement of a pair of Barlow's high-pressure kiers, one being given in section. The two kiers a, h are of strong boiler-plate iron ; p' is a false bottom, consisting of smooth water-worn stones, or a cast-iron grating, on which the cloth is laid ; d is the distributor which acts also as a strengthening stay ; the upper portion is perforated and closed by a stop at some distance fiom the bottom ; the block h at the bottom of the distributor is pei-foi'^ted to allow liquor to pass from the kier : alxjve, the distributor is connected with the two-way tap <, by which steam is admitted from the main pipe m, and by the revei'sing of which the steam is shut off and liquor admittelace largeh^ during this exposure, hypochlorous acid being then liberated by the action of the carbonic acid of the air. It is essential that the bleaching-powder solution should not be too strong, otherwise the cloth may be tendered or be partially changed into oxycellulose, and thereby be apt to attract certain colouring matters in the dye-bath, or to contract brown stains during subsequent steaming processes. For the same reason the solution of bleaching-powder should be entirely free from undissolved particles. The bleaching power of the liquor should be main- tained as constant as possible by having a continual flow of fresh bleaching-powder solution into the machine, and by occasionally testing how much of the liquor is required to decolorise a specially prepared standard solution of arsenate of soda, tinted with indigo extract or cochineal decoction. C. White-sour. — This operation does not differ from the lime-sour already described. Its object is to com- plete the bleaching action by decomposing any " chloride of lime " still in the cloth, also to remove the lime, the oxidised colouring matter, and any traces of iron present. The cloth usually remains saturated with the acid a few hours. 7. The Jlnal washing must be as thorough as possible. It is usually performed by the square beater machine, illustrated in Fig. 62. The squeezing is done by the machine shown in Fig. 65. After squeezing, the cloth is again opened out to the full width, previous to drying. This is effected by allowing a lengthened portion of the chain of cloth to hang loosely and horizontally, and in this position to pass between a pair of rapidly revolving double-armed scutchers, which shake out the twists from the horizontal length of cloth. On leaving the scutchers, the piece passes in a state of tension over Chap, v.] TURKEY-RED-BLEACH. 85 one or more rollers provided with spiral projections, which tend to open out the cloth still more thoroughly ; in this state it passes round the steam cylinders of the drying machine illustrated in Fig. 79. The average length of time required for the madder- bleach is four to five days. TuEKEY-RED-BLEACH. — When calico is intended to be dyed Turkey-red it is not necessary to give it the madder- bleach, since no white ground has to be preserved. Certain modifications, too, are introduced ; it is found, for example, that singeing, and the application of bleach- inpj-powder which causes the formation of oxycellulose, interfere with the production of the most brilliant colour. The apparatus employed being similar to that already described, it is only necessary to give the following summary of the operations usually carried out : 1. Wash. 2. Boil in water for two hours and wash. 3. Ley-boils: Ist, 90 litres caustic soda, 70° Tw. (Sp. Or. 1-35), boil ten hours and wash. 2nd, 70 litres, ditto, ditto.! 4. Sour: sulphuric acid, 2« Tw. (Sp. Gr. 1-01) steep two hours. 6. Wash well and dry. The above quantities of materials are intended for 2,000 kilos, cloth, with low-pressure kier. Market-bleach. — In market-bleaching the essen- tial difierence consists in the absence of the boiling with resin-soap, and the introduction of tinting the cloth with some blue colouring matter previous to drying. With many bleachers, the operation of chemicking comes be- tween the two ley-boils, and not after them, as is usually the case. Other bleaching agents than chloride of lime have been proposed for cotton, and even partially adopted — e.^., hydrogen peroxide, permanganate of soda, &c. — but none have yet been able to supplant it, principally 86 DYEING OF TEXTILE FABEICS. [Cliap. YI. because of tLeir greater cost. The same may be said regarding tLe mode of bleaching by means of the electro- lysis of alkali chlorides CHAPTER VI. LINEN BLEACHING. 58. The bleachinsf of linen is more or less similar to that of cotton, although it is decidedly more tedious, owing to the larger proportion of natural impurities present in the flax fibre, and the greater difficulty of removing or decolorising them. These impurities consist j^rincipally of the brovm insolulOe pectic acid, which remains on the fibre after the retting process, to the extent of 25 — 30 per cent, linen is bleached in the form of yam, thread, and cloth. 59. Bleaching of Linen Yarn and Thread. — Linen yam is frequently only partially bleached, and one distinguishes yarns which are " half white " (cream), "three-quarters white," and ''full white." The following is an outline of the general method of bleaching linen yam as at present adopted in Ireland. The percentages relate to the weight of yarn under treatment : — 1. Boil: 10 per cent, soda-ash, boil 3 — i hours; wash and squeeze. 2. Beel : bitching powder solution, ^'^ Tw. ; reel 1 hour ; "wash. 3. Sour: sulphuric acid, I'' Tw., steep 1 hour; wash. 4. Scald : 2 — 5 j)er cent, soda-ash, boil 1 hour ; wash, o. Eeel : as No. 2 ; wash. 6. Sour : as Xo. 3 ; wash well and dry. At this stage the yarn should be "half white." If it is requii^ed " three-quarters white," the drying Chap.Vl.] LIXEK YAtlif feLEACUiXG. ^7 is omitted, and operations 4, 5, and 6, are repeated with the following slight modifications : (a) after the " scald ' the yarn is "grassed," i.e., spread on the grass m a field for about a week ; (6) instead of reeling the yarn m the solu- tion of bleaching-powder, it is simply steeped m it tor lO—V-y hours, an operation which is analogous to tlie chemicking of cotton yam (p. 72), and usually called the '*' dip." , . ,. 1 If the yarns should be "full white' the same operations are again repeated once or twice, the duration of grassing being varied according to necessity and the weather. In each succeeding operation the concentration of the solutions employed is diminished. The operation of boiling takes place in ordmary open or low-pressure kiers, while those of dipping, sour- inc^ and washing, are best performed in the apparatus illustrated in Fig. 24. In many establishments, however, the dipping and souring are effected by simply steeping the yarn in stone tanks filled with the necessaiy liquids, but owing to the absence of all circulation of the latter, this plan cannot be so efiective. The washing is fre- quently done in wash-stocks, or dash-wheels, but this also is not good, because it tends to make the yam rough. . The mode of applying the bleachmg-powder solution in the earlier stages by " reeling," is peculiar to linen yarn bleaching. Its primary object has probably been to ensure regularity of bleach, but since the carbonic acid of the afr decomposes the calcium hypochlorite more readily by this means, and liberates hypochlorous acid within the fibre, as it were, the bleaching must be more thorough and greatly accelerated. The reeling machine consists of a large shallow stone cistern holding the solution of bleaching-powder, and provided with a movable framework supporting a number of reels. On these are suspended the hanks of yam in such a manner that only their lower ends dip mto the liquid Each single reel can be readily detached it 88 DYEING OF TEXTILE FABRICS. [Chap. VI. necessary, or, by means of a hydraulic lift, the whole fi'amework with reels and yarn can be raised and withdrawn from the liquid, and at once transferred to another and similar cistern for the purpose of washing, ttc. Some bleachers use this machine for scalding. It is said that better results are obtained if the calcium hypochlorite is replaced by the coiTesponding magnesium compound. Probably the best agent to use M'ould be sodium hypochlorite, since there would then be no formation on the fibre of any insoluble carbonate, and washing might largely replace the souring, in which case weaker acids even than those mentioned could be used. Since calcium chloride is more soluble than the sulphate, it seems likely that where calcium hypo- chlorite is used, hydrochloric acid would be better as a souring agent than sulphuric acid. 60. Bleaching of Linen Cloth. — The following is an outline of a modern Irish process for 1 ,500 kilos, brown linen (lawns, handkerchiefs, (fee), with low-pressure kiers : 1. Lime-boil : 125 kUos. lime, boil 14 hours ; wash 40 minutes in stocks. 2. Sour: hydrochloric acid, 2|° Tw. (Sp. Gr. 1-0125), steep 2 — 6 hours; wash 40 minutes in stocks ; "turn hank," and wash 30 minutes in stocks. 3. Ley-boils : 1st, 30 kilos, caustic soda (soHd), 30 kilos. resin, previously boiled and dissolved together in water ; 2,000 litres water; boil 8—10 houi^s ; run off liquor, and add — 2nd., 15 kUos. caustic soda (solid), dissolved; 2,000 Htres water, boil 6 — 7 hours ; wash 40 minutes in stocks. 4. Expose in field 2 — 7 davs, according to the weather. 5. Chemick : chloride of lime solution, |° Tw. (Sp. Gr. 0-0025), steep 4 — 6 hours ; wash 40 minutes in stocks. 6. Sour : sulphuric acid, 1° Tw. (Sp. Gr. 0-005j, steep 2—3 hours ; wash 40 minutes in stocks. 7. Scald : 8 — 13 kilos, caustic soda (sohd) dissolved, 2,000 litres water, boil 4 — 5 hours ; wash 40 minutes in stocks. 8. Expose in field, 2 — 4 davs. 9. Chemick -. chloride of lime solution, i'^ Tw. (Sp. Gr. 0-00125), steep 3 — 5 hours ; wash 40 minutes in stocks. Chap. VI.] LINEN CLOTH BLEACHING. 89 The goods are examined at this stage ; those which are sufficiently white are soured and washed, and those which are not are further treated as follows : — 10. Eub with rubbing boards and a strong solution of soft soap. 11. Expose in field 2 — i days. 12. Chemick : chloride of lime solution, i° Tw.(Sp. Gr.00003), steep 2 — 4 hours; wash 40 minutes in stocks. 13. Sour: sulphuric acid, 1° Tw. (Sp. Gr. 0-005), steep 2— 3 hom-s ; wash 40 minutes in stocks. When the cloth (cream linen) is made of yarn already partially bleached, a less severe process is re- quired, e.g., less lime is used in the lime-boil ; only one ley-boil is given, and that with resin-soap instead of caustic soda ; weaker chloride of lime solutions are used ; the scald is effected with soda-ash solution ; and operations 8 and 9 are omitted. What is known as " brown holland " is a plain linen cloth which has had little or no bleaching, but only a short boiling in water, or in weak soda-ash solution, followed by a weak souring. It possesses, therefore, more or less the natural colour of the retted flax fibre. The washing is usually effected in the wash-stocks (Fig. 52), but sometimes, and with advantage too, in so- called slack-washing machines. These are similar in construction to that represented in Fig. 60 ; the washing trough, however, is divided by wooden spars into several compartments, each capable of holding several yards of slack cloth between each nip. The '' rubbing " referred to is a characteristic feature in linen cloth bleaching, and has for its object the removal of small particles of brown matter called " sprits." It is effected by a special machine which con- sists essentially of a pair of heavy corrugated boards rest- ing on each other ; the upper one is moved lengthwise to and fro, while the pieces are led laterally bet^veen them. The exposing of the goods in a field to the in- fluences of air, moistui'e, and light, or "grassing," as it 90 DYEING OP TEXTILE FABRICS. [Chap. Vl. is technically termed, is still veiy generally adopted in order to avoid steeping too frequently in solutions of bleacliing-powder, and thus to preserve as much as possible the sti'ength of the fibre. " Turn-hanking " consists in loosening the entangled pieces and refolding them, so that every part may l>e exposed to the action of the hammers of the wash stocks ; the operation is introduced as often as requii'ed at various stages of the bleaching process, but especially after "vrashing in the stocks. 61. Chemistry of Linen Bleaching. — Dm-ing the several boiling.s w-ith lime, soda-ash, caustic soda or resLQ-soap, the insoluble brown-coloured pectic acid of the retted fibre is decomposed, and changed into metapectic acid, which cx)mbines with the alkah to form a soluble compoimd. According to the origin of the flax, the loss which it thus sustains may vary from 1.5 to 36 per cent. By the application of bleaching-powder alone, the brown jjectic matters are bleached only with great difficulty, and even then only by using " chloride of lime " .solutions of such concentration that the fibre itself is ap»t to be attacked After a number of successive boilings with alkali, however, the goods retain merely a pale grey coloui', which is readily bleached by comparatively weak solutions without injuiy to the fibre. The rational mode of bleaching linen would seem to be, therefore, to defer the application of the bleaching- ix)wder until the pectic mattei-s have been almost or entirely removed by lime and alkaline boilings, although, in practice, this plan Ls never strictly adhered to. A single ley-boil scarcely remove more than 10 per cent, of the pectic matters, and since their presence in such large proportion prevents the solutions of bleaching- powder fi'om decolorising the whole of the grey matter at one operation, the usual plan is to alternate the alkaline boilings with dilute chloride of lime treatments ; the more so because it is considered that a slight oxidation of the pectic mattei'^ facilitates their removal by the Chap. VII. I WOOL SCOURiyG. 91 alkaline boilings, and that the latter predispose them to oxidation. Well-bleached linen ought not to be discoloured when steeped in a dilute solution of ammonia ; if by this treat- ment the linen acquii'es a yellow tint, it is a sign that the pectic matters have not been entii-ely removed. The usual period requii-ed for bleaching brown linen varies from three to six weeks. CHAPTER VII. WOOL SCOURING AND BLEACHING. 62. Object of ScouringWooL— The"scouring"of wool has for its object the complete removal of all tliose natural and artificial impurities (yolk, dirt, oil, eping the cloth opened out and free from creases previous to its passage between the squeezing rollers a, b, which are prefei'ably of iron, in order to give a more equal pressure across the whole width of the cloth- Immediately below these rollers is the trough c containing the scouring solution. The perforated water- pipe H is used when the pieces are washed in this machine after scouring. 67. Scouring of Union Goods. — The scouring of thin Chap. YII.J WOOLLEN' CLOTH SCOURING. 109 materials with cotton warp and woollen weft presents certain difficulties. The different hygroscopic, elastic, Fig. 37. — ^Woollen Cloth open-width Scoimug Machine. and other physical properties of cotton and wool, cause such materials, if simply scoured in the ordinary way, to contract or shrink irrejjularlv over the whole surface of the fabric, so that they assume, when dried, a rough 110 Chap. VII.] CRABBING. Ill shrivelled appearance which renders them quite unsale- able. Special appliances and methods are in consequence required. The scouring of thin union goods comprises the operations of Crabbrag, Steaming, and Scouring. (a) Crabbing or Fixing. — The object of this and the following operation is to prevent the material from ac- quiring the "cockled/' " curled," or shrivelled appearance above alluded to. It also imparts a permanent and inde- structible lustre and finish of a peculiar quality, which is not removed or affected by any subsequent operation. Fioj. 38 shows the arranorement of a treble crabbin^j machine. The cloth A wrapped on the roller or beam b is passed in the open width, and in a state of tension, below the roller d and throuo^h boiling water contained in the vessel c, then immediately between the pair of heavy iron rollers b and e, under great pressure. It is at once tightly wrapped or beamed on the lower roller b, there- fore, while still revolving in the hot water. The process is repeated with boiling water in the second trough, and again with cold water in the third trough. The tension of the cloth and the pressure of the rollers are varied according to the quality of the goods, and the particular feel, lustre, and finish ultimately required. With such goods as must have subsequently a soft feel or '• handle " — e.g., Cashmeres, Coburgs, d'c, — no pressure at all is employed, the pieces being simply beamed tightly on the bottom roller. (6) Steaming. — The pieces are unwrapped from the last crabbing roller [i.e., from the cold water), and tightly wrapped on the perforated revolving iron cylinder g. Steam is admitted through the axis of this cylinder for the space of about ten minutes, or until it passes freely through the cloth. In order to submit every portion of the piece to an equal action of the steam, the process is repeated with the cloth tightly beamed on a second and similarly perforated roller g', so that those portions of the cloth which were on the outside are now in the interior. 112 DYEING OF TEXTILE FABRICS. [Cliap. YTT. These perforated steam-cylinders are frequently quite separated from the crabbing machine, and then usually rest on a steam nozzle in a vertical or horizontal position. (c) Scouring. — The cloth, being now " set," as it is t^echnically termed, is scoured for half-an-hour or more, with soap solution at 40° — 50° C. in the " Dolly " or *' open width " machine, above described. The sequence of operations as here given, although frequently employed, is not altogether rational. The best results are obtained by crabbing and scouring simultaneously, and then steaming. To accomplish this, the boiling water in the crabbing troughs is merely re- placed by a solution of soap, sodium carbonate, or other scouring agent. It is found that to steam the cloth in its oily state exercises some injurious action, and renders it liable to contract dark stains during mordanting, espe- cially if stannous mordants are employed. It is possible that the oil is more or less decomposed, and a portion becomes fixed on the fibre. 68. Bleaching of Wool. — Wool is generally bleached either in the form of yam or cloth, but only when it is intended to remain white, or if it has to be dyed in very light delicate colours. The bleaching agent universally adopted is sulphur dioxide. According to the state in which it is applied, either in the form of gas or dissolved in water, one may distinguish between " gas bleaching " and "liquid bleaching," and of these the former is more generally emploj^ed. In recent years that excellent bleaching agent, hydrogen dioxide, has become an article of commerce, and no doubt would be more largely used in woollen bleaching than it is at present, if only it were less costly. Gas Bleaching^ Stoving, or Sulphuring. — Yarn is first scoured andwell washed, then suspended on poles and placed in the sulphur stove — a spacious brick chamber which can be charged with sulphur dioxide. The necessary amount of sulphur (in the proportion of 6 — 8 per cent, of the wool to be bleached) is placed in an iron pot in one corner of the Chap.Vn.l WOOLLEN' CLOTH ELEACHINO. 113 Chamber, and ignited by inserting -^'^'j^'l^'^^f'^lZ i, then closed, and the moist yarn is left exposed to tae action of the gas for six to eight hours or even over- night Afterwfrds the chamber is thorough yventdated, the Yarn is removed and well washed in water. &eavy woollen cloth, such as blanketing, is treated ia exactly the same manner as yarn, but with tluu Fig. 39.-Sulpliur Stove for WooUen Cloth Bieaclui^g ^ -ol .n merino etc.— the operation is preferably ^'Ten'framt tavin'role^s above and helow. The rTof WdTe' uLd with lead and heated -ths^am \r. nrrlpr to nrevent condensation. Ihe sto^e ib E;ed\l su%C dioxide as already described^ or, I 114 DYEING OP TEXTILE FABRICS. [Chap. YIL under and over the rollers, and passes out again by the same oj>ening. The number of times the cloth is passed through the stove varies according to the appearance of the cloth- In liquid bleaching, the wooUen material is worked and steeped for several hoars either in a solution of sulphurous acid or in a solution containing sodium bi- sulphite (5 — 50 grams per litre;, to which an equivalent amount of hydrochloric acid has been added ; it is after- wards thoroughly washed. A better method, however, is that in which the wool is treated with sodium bisulphite and hydrochloric acid in separate baths, whereby the sul- phurous acid is generated within the fibre, aiid, being in the nascent state, acts more powerfully upon tht colouring matter of the wooL Goods which have to remain white are tinted with some blue or bluish-violet colouring matter {e.g.j ground indigo, indigo-exti^act, aniline blue, jfcc), either before or after the bleaching operation, in order to counteract the yellow colour of the wool which is so apt to return. The principle hf^re applied is that of the complementary coloui-s, which when mixed in due proportion produce white light. Blue is complementaiy to yellow. The bleaching action of stilphur dioxide is most probably due to its reducing action upon the natural yeUow colouring matter of the wool ; another explanation, however, is that it combines with the latter to form a colourless compound- Certain it is that the effect is by no means permanent ; fi-equent washing of bleached wool in alkaline solutions always tends to restore the yellow apf>earance of the fibre. Either oxidation is thus in- duced, or the colourless sulphite is decomposed, and the original coloiu'ing matter is precipitated on the tibre. The airent par excellence for liquid bleaching is hydro- gen dioxide (HjO,). Even yellow - coloured wool is bleached by it to a white, possessing a biilliancy and parity unattainable by the ordinary methods. The woollen material is steeped for several hours in a diluu^ Chap. VIII.] UNGUMMING OF SILK. 115 and slightly alkaline solution of commercial hydrogen dioxide and afterwards well washed, first with water acidulated with sulphuric acid, and afterwards with water on' v. ■ CHAPTER VIII. SILK SCOURING AND BLEACHING. 69. Object of Scouring Silk. — The object of scouring silk is to remove from the raw fibre a greater or less proportion of the silk-glue which envelops it, and thus to render it lustrous and soft, and better fitted for the operation of dyeing. According to the amount of silk- glue removed, the product of the scouring operation may be either hoiled-off silk, souple silk, or ecru, for each of which, indeed, a different treatment is necessary. 70. Boiled-off Silk is the name given to silk from which practically the whole of the silk-glue has been removed. It exhibits most fully the valued properties of lustre, softness, tfec. Two operations are necessary for its production, namely, "stripping" and " boilirig-oft'." (a) Stripping or Ungumming (Fr., degomrriage). — The object of this operation is to soften the silk, and to re- move the great bulk of the silk-glue and also the colouring matter. The hanks of raw silk are suspended on smooth wooden rods, and worked by hand in rectangular copper troughs, in a solution of 30 — 35 per cent, soap, heated to 90^ — 95° C. When the water is very calcareous, the silk is first rinsed in a weak, tepid solution of sodium carbonate. The best plan is to correct the water pre- viously. Rinsing in dilute tepid hydrochloric acid before ungumming is also good, since it removes calcareous and other mineral matters from the silk, and prevents their action in the soap bath. Weighted ecru silks cause great inconvenience in the ungumming : the soap bath is 116 DYEING OF TEXTILE FABRICS. [Cliap. VIII. precipitated, the fibre becomes tarnished and sticky, and the nngumming is rendered difficult and incomplete. Dui-ing the stripping operation the silk at first swells up and becomes ghitinous, but, after a short time, when the silk-glue dissolves ofi', it becomes fine and silky. It is best, especially vrhen the silk is intended for whites or delicate coloui-s, to work it successively in two or three separate baths, for about twenty to twentv-five minutes in each, and to pass fresh lots of silk through in regular order. When the first bath becomes char^red with silk- glue it is renewed, and then employed as the last bath. Each soap bath should be utilised to the fullest extent compatible with excellence of result It is well to bear in mind that too prolonged contact with boiling soap solution is not good, since a little of the colouring matter of the glue is apt to be attracted by the fibre, and the silk loses substance, strength, and purity of white. The waste soapy and glutinous liquid obtained is called "boiled-ofi"" liquor, and serves as a useful addition to the dye-bath when dyeing with the coal-tar colours. After *• stripping,"' the hanks are rinsed in water, in which a small quantity of soap and sodium carbonate h£LS been dissolved. (b) BoiUng-of (Fr., la cuite). — For the purpose of removing the last portions of silk-glue, «fcc., and to give the silk its full measure of softness and lustre, it is now placed in coarse hempen bags, technically called "pockets," about 15 kilograms in each, and boiled from half an hour to three hours (according to the quality of the silk) in large, open copper vessels, with a solution of 10 — 15 j)er cent, of soap. The silk is then rinsed in tepid water, rendered slightly alkaline by the addition of sodium carbonate in order to prevent the precipitation of lime soap on the silk. It is finally washed well in cold water. The waste soap liquor may be used for " stripping.'"' For some articles, the silk is boiled on wooden rods and not in pockets. The soap employed, both for '• stripping ' and for Cbap. VIII.] SOUPLIXG OF SILK. 117 "boiling-off" should be of the best quality. Other things being equal, those soaps are to be preferred which wash off most readily, and leave an agreeable odour. When, however, the silk has subsequently to undergo a number of soaping and other operations — e.g. J in weighted blacks — the odour of the soap used in boiling-otf is of little consequence. Oleic acid soap may be recommended in such a case, but for silk destined to be dyed in light colours or to remain white, a good olive-oil soap is preferable. By scouring with soap in the above manner, Japanese and Chinese silks lose 18 — 22 per cent, of their weight and European silks 25 — 30 jDcr cent. Stretching (Fr., etirage). — When the silk is well softened during the stripping process, but not really un- gummed, it may be conveniently stretched to the extent of 2 — 3 per cent, without injury ; indeed, it acquires increased lustre by stretching. The operation may be per- formed either by the lustreing or the stringing machine. Stoving. — When the silk is intended to remain white, or is to be dyed pale colours, it is bleached by exposing it in a moist condition to the action of sulphurous acid in closed chambers. The operation, which lasts about six hours, may be repeated two to eight times, according to the nature of the silk. Ten kilograms of silk will require about half a kilogram of sulphur. After stoving, the silk is well washed till free from sulphurous acid. For reference to the bleachinor with a mixture of nitric and hydrochloric acids, see next page. 71. Souple Silk is silk which has been submitted to certain operations, to render it suitable for dyeing, &c., without causing it to lose more than 4 — 8 per cent, of its weight. The object of soupling is, indeed, to give to raw-silk, if possible, all the properties of boiled-off silk, with the least loss of weight ; considerable perfection has already been attained in this direction. Souple silk is not so strong as boiled-off silk, and is used for only tram. The process of soupling consists essentially of two 118 DYEING OF TEXTILE FABRICS. [Chap. Vin. operations, first, the softening ; and second, the soi'.pling proper. With yellow silk, and whatever is intended to be dyed light colours, the operations of hhachiny and stoving intervene. (a) Softening. — The raw silk is worked for one to two hours in a solution of 10 per cent, soap, heated to 25*^ — 35° C. The object of this operation is to soften the fibre, and remove the small quantity of fatty matter present, so as to facilitate the operations which follow. {b) Bleaching. — The silk is worked in stone troughs for eight to fifteen minutes in a dilute solution of aqua- regia'^" Tw. (Sp. Gr. 1-02), heated to 20° — 35° C. It is afterwards washed well till free from acid. The aqua-regia is prepared by mixing together five parts, by weight, of hydrochloric acid, 32° Tw. (Sp. Gr. 1T6), wdth one part of nitric acid, 62" Tw. (Sp. Gr. 1'31), and allowino: the mixture to stand for four or five davs at a temperature of about 25° — 30° C Before use it is diluted with fifteen volumes of water. For the aqua- regia may be substituted sulphuric acid saturated with nitrous fumes, or a solution of the so-called " chamber- crystals " obtained in the manufacture of sulphuric acid. The silk must not be worked too long in the acid liquid, otherwise the nitric acid causes it to contract a yellowish tint which cannot be removed. The moment the silk has acquired a greenish -gi'ey colour it should be withdraAvn from the bath, and well washed with cold water. (c) Storing. — This operation is similar to that already described {see previous page). It renders the silk hard and brittle. Without removing the sulphurous acid, however, it is at once submitted to the following operation- {d) Sowpling (Fr., asson.plissage). — Tlie silk is -worked for about an hour and a half, at 90° — 100° C, in water, containing in solution 3 — 4 grams cream of tartar per litre. The silk becomes softer and swells up, and being thus rendered more absorbent, it is better adapted Ohap. VTIL] BLEACHING OF SILK. 119 for dyeing. Tlie operation of soiiplinc^ is a somewhat deli- cate one, and needs considerable judgment and practice. The solution must not be too hot, nor must the immer- sion of the silk be too prolonged, otherwise the loss in weight is excessive, and the result is unsatisfactory. After soupling, the silk is finally worked in a bath of tepid water. Souple-silk will bear warm acid baths sub- sequently, but not alkaline or soap baths beyond a tem- perature of 50" — 60° C, otherwise it loses silk-glue, and is more or less spoiled. The operation of soupling is some- times performed on raw-silk which has been previously submitted to other operations, as, for example, in the dyeing of so-called black souples. A satisfactory explanation of the theory of soupling has not yet been given. The cream of tartar probably acts as an acid salt merely, and although it gives the best results, it can be replaced by a solution of sodium or magnesium sulphate acidified with sulphuric acid, or even by very dilute hydrochloric acid. It is curious that silk is rendered less tenacious by soupling than by boiling-ofi'. 72. Ecru Silk is raw-silk which at most is sub- mitted to washing, with or without soap, and bleaching. The loss of weight varies from 1 to 6 per cent. Un- bleached ecru silk is only dyed in one or two different shades of black. 73. Bleaching of Tussur Silk. — This may be accom- plished according to the method proposed by M. Tessie du Motay, in which barium binoxide is the agent em- ployed. Free baryta hydrate is first removed from the binoxide by washing the latter with cold water, and a bath is then prepared, containing binoxide in the propor- tion of 50 — 100 per cent, of the weight of silk to be bleached. The silk is washed for about an hour in the bath heated to 80° C, then washed and passed into dilute hydrochloric acid, and washed again. If the white is not good, the operations are repeated, or one may also 120 DYEING OF TEXTILE FABRICS. [Cliap. VIII. complete the bleaching by washing the silk in a solution of potassium permanganate and magnesium sulphate, and afterwards in a solution of sodium bisulphite, to which hydrochloric acid has been added. Although barium binoxide is little soluble in water, at the temperature of the bleaching bath it gives up oxygen to the fibre by degrees, even without the addition of any acid, so that the bleaching takes place gradually. During the immersion the silk also absorbs a certain amount of the binox:^,de, probably as hydrate, so that on the subsequent passage into acid there is liberated with- in the fibre hydrogen dioxide, which, being in the nascent state, bleaches to the best effect. The chief difficulty of the process consists in the fact that, by long contav3t with the barium binoxide the silk becomes dull, harsh, and tender, but with care the process can be made to yield excellent results, and it is, indeed, already adopted in practice. Hypochlorite of ammonia has been employed, but with less success. The very best bleaching agent for Tussur and also Mulberry silk is hydrogen dioxide. It is applied in the same manner as indicated on p. 114 for wool. Tussur silk is bleached for the purpose of dyeing it in light colours. 121 WATEE IN ITS APPLICATION TO DYEING, CHAPTEPv IX. WATER. 74. Soft and Hard Water. — Water occurs as natural vmter in the form of invisible vapour permeating the air. When the temperature becomes sufficiently low, it con- denses and becomes visible as dew, fog, or cloud, or is precipitated in the form of rain. The original source of natural water is the ocean. This is in a state of constant evaporation, and the vapour produced just as constantly undergoes the condensation alluded to. In- deed, a gigantic process of natural distillation is here presented, and, as one would anticipate, rain-water is the purest form of natural water. A portion of the rain-water sinks into the earth until it reaches some impervious layer, from which it may be pumped up as ivell-ivater, or it flows underground, and eventually reappears on the surface as a spring, which frequently forms the source of a brook, or river. Another portion of the rain-water never penetrates the soil, but simply drains off the land, and forms the so- called surface-ioater, which also goes to form rivers. The solvent power of water is so considerable that })oth spring and river water always contain certain mineral and vegetable matters, the nature of which 122 DYEING OF TEXTILE FABRICS. [Chap. IX, varies according to the chai-acter of the rock or soil through or over which it has passed. If the geological strata are composed of snch hard insoluble rocks as granite and gneiss, the water remains comparatively free from impurities, and whether it flow as a river or rise as a spring, it "v^ill be what is termed a " soft " water. If, on the contrary, the water during its subten-anean course meets with rocks containing such a soluble con- stituent as rock-salt, it becomes brine ; if it encounters a stratum of lime-stone, oolite, chalk, new red sandstone, (tc, it dissolves a certain portion of it, and becomes magnesian or calcareous, and constitutes on its reappear- ance what is called a " hard " water. Common lime- stone being generally of a less permeable nature than magnesian limestone, does not yield such hard water as the latter. Again, if the water passes through or over rocks containing iron in some form or other, it takes up some of the ii'on and becomes a so-called '* chalybeate " water. When the rain-water dizains from boggy moorland, a certain portion of the more or less decomposing vege- table matter dissolves, and the water is usually brown- coloured. The natural impurities of water which concern the dyer may be either suspended or dissolved, and of these the latter are the most im})ort,ant. A constant supply of clear water is certainly an indispensable requisite, but the means of purifying muddy water are comparatively simple, and the chemical nature of the susj)ended matter generally possesses little or no interest. The dissolved constituents of water, however, are equally, or even more, injurious, and to effect their removal is much more diffi- cult, involving as it does the employment of chemical means of purification. As a general rule, river water contains the largest amount of suspended and vegetable matter, and the least amount of dissolved constituents, whereas spring and well water bear the opposite cha- racter. Chap. IX.] IMPURITIES IX WATER. 123 75. Calcareous and Magnesian Impurities. — These are at once the most frequently occurring, and the most injurious of all impurities. Thej are usually present as bicarbonates, less commonly as chlorides and sulphates. The latter are generally less injurious than the former. The presence of lime is shown, if the addition of a solution of ammonium oxalate to the water in question gives a white precipitate of calcium oxalate. On evapo- rating such a water to a small bulk it becomes turbid. If, then, the addition of hydrochloric acid produces effervescence, and renders the solution again perfectly clear, it is an indication that all the lime is present as bicarbonate. If there is no effervescence and no clearing, it is probably all present as sulphate. Etiervescence and partial clearing denote the presence of both sulphate and carbonate. Should there be no turbidity on evaporation, lime is either absent altogether, or it is probably present as chloride or nitrate. The presence of magnesia is detected, after lime and alumina have been removed by means of ammonia and ammonium oxalate. The filtered liquid is concentrated by evaporation, and mixed with a solution of phosphate of soda and ammonia j magnesia is present if a white crystalline precipitate is thereby produced. The separa- tion, however, of lime and magnesia has little or no importance for the dyer. The presence of bicarbonates is further detected by the addition of a clear solution of lime-water producing a white precipitate. Sulphates are present if an addition of hydrochloric acid and barium chloride gives a white precipitate. A white curdy precipitate, which is produced on add- ing nitric acid and silver nitrate, denotes the presence of chlorides. The injurious influence of magnesian and calcareous water cannot be overrated, and very specially because of its property of precipitating soap solutions. Hard water only produces a froth or lather with soap after 124 DYEING OF TEXTILE FABRICS. a'hap. IX. the whole of the calcium and magnesium compounds present have been precipitated as insoluble lime and magnesia soaps, the latter of which may be distinguished from the former by their more objectionable curdy character. By employing a soap solution of a standard strength, it is possible to calculate approximately the amount of calcium and magnesium compounds present. Details of this method of determining the hardness of water (Clark's) are given in most text-books of chemical analysis. It is well to note that, according to Clark's scale, a water with one degree of hardness contains one srrain calcium carbonate per gallon, but after the newer scale of Frankland, one degree of hardness signifies that the water contains one gram of CaCOg in 100,000 grams water. To reduce the degrees of the latter to those of Clark's scale it is simply necessary to multiply by seven-tenths. In all those operations where large quantities of soap are employed, it is evident that the use of a hard water entails a considerable loss of soap. One kilogram of CaO decomposes about 15 '5 kilograms of ordinary soap containing 30 per cent, of moisture. After making a soap -analysis of the water, and knowing the quantity of the water employed, it is easy to calculate the annual loss of soap (about one-sixth) occasioned by the hardness of the water. Taking the monthly consumption of soap in London as 1,000,000 kilos., it is estimated that the hardness of the Thames water causes an expenditure of 230,000 kilos, more soaj) per month than would be lequired if soft water were used. This is, however, by no means the only disadvan- tage. The precipitated earthy soaps are more or less of a sticky nature, and adhere so tenaciously to the fibre that they cannot be removed by ordinary technical processes. In the scouring of wool, or of silk, they render the fibre more or less impermeable, so that neither mordant nor colouring matter can be afterwards properly Cl,al,.IX.] IMPURITIES IN WATER. 125 fixed thereupon, and irregute development of colour "■'"'when the soap solutions are applied oAardyeing- ii The clearin- of Turkey-red, milling of woollen fe^kc^:, "he>ipitateense, this method is unsatisfactory, since the major portion of the earthy soaps, «i:c., remains disseminated in the water in a finely-divided state. Water corrected in this manner is necessarily left in an alkaline condition from the alkali of the soap remaining behind, and of course the amount of alkaline carbonate left is equivalent to that of the earthy salts removed, thus CaH^CCOs), 4- 2CisH330psa =: Ca'CisH^jOoyj -H Caldnju la-carbonate. Soap. Ume-soap. Xa^COa -L COg 4- H.O. Sodhun eriment. Three pieces of clean white textile material — wool, silk, and cotton — are immersed in a moderately stroucj aqueous solution of acid Indigo Extract, and are kept in continual movement by stinnng. while the liquid is gradually heated to the boiling point. If the pieces are then taken out and well washed with water they present a remarkably different aspect ; the wool and silk have become dyed, and appear pale or deep blue according to the amount of colouring matter employed, while the cotton is not dyed, or, at most, becomes slightly stained. If the experiment is repeated with many other colourinfr matters — e.g., Magenta, Methyl Violet, vdth certain monogenetic colouring matters, for instance. Indigo. The presence of the fibre in the third experiment cited above, is not a condition essential to the de\'elo]> ment of the coloui', as can be readily enough shown by the foD owing experiment : — Make a dilute solution of aluminium sulphate, and render it somewhat basic and more sensitive by neutralising a portion of its sulphuric acid with sodium carbonate ; add now t6 the still clear solution a little alizarin, and shake the mixture vigor- ously, or heat it a little. A red-coloured body is very soon produced in the form of an insoluble precipi- tate, especially if a calcium salt be also present. It would appear in this case that the colouring matter enters into chemical combination with the aluminium, or with a very basic salt of the same. Analogous but variously- coloured precipitates are produced on substituting decoctions of Cochineal, Persian berries, Logwood, . The technical name given to solutions of the various aluminium acetates and sulphate-acetates used in practice, is red liquor, because they ai*e universally employed by the calico-printer and cotton-dyer as the mordant for producing alizarin reds. Considerable licence is apparently taken in pi'^ctice in the manufacture of " red liquors " requii'ed for different purposes and styles of work, both with regard to the particular ingi-edients used, and their relative proportions. Apart from the fact that their real value is determined by practical results, the above considei-ations show that numerous variations in composition are j^ossible, which cause them to behave ^ery differently. The following may be taken as representative of the Chap. XI.] ALUMINIUM MORDANTS. IGO innumerable recipes adopted in tlie manufacture of various red liquors : — gms. gms. gms. gms. gms. gms. gms, gms. gms. gins. Water . . . 250 300 400 200 400 403 400 495 — — Alum . . . 100 100 100 lOJ 100 KjO — — — 100 Aluminium sulphate — — — — — — 120 120 68 — Lead acetate . . 100 75 66-6 80 90 100 100 122-5 — — Sodium carbonate ) ^o 10 10 - - - _ - _ - cryst. (10 aq.) ) Chalk ..._ — — — — — 8-5 7-9 8 6 Calcitim acetate") 24°Tw.(Sp.Gr. ^ ______ _ — 252 280 1-12) . . ) The red liquors of commerce are prepared by the double decomposition of normal aluminium sulphate and commercial acetate of lime. The so-called common red liquor contains a certain proportion of undecomposed aluminium sulphate, and is a crude sulphate-acetate, while in that known as tin red liquor, the decomposition has been made as complete as possible, so that it represents a crude normal aluminium acetate. These red liquors always possess a brownish appearance, from the presence of empyreumatic matter. Application of the Aluminium Acetates and Sulphate- Acetates to the several Fibres. 102. Ajoplication to Cotton. — These are the alumi- nium mordants p)ar excellence of the calico-printer. Their solutions are suitably thickened by means of flour, starch, or dextrin, and printed upon the calico and dried. Excessive heat in the drjdng must be carefully avoided {e.g., by substituting hot plates, hot air, (tc, for steam-heated cylinders), especially in the case of those mordants which are most readily dissociated (basic salts), otherwise poor and irregular colours are subsequently obtained. When this happens, it is said that the printed mordants have been " bui'iied" ; the mordant fixed upon the fibre has probably been dehydrated, or has undergone some physical change, which renders it less capable of attracting colouring matter in the subsequent dye- bath. 170 DYEING OF TEXTILE FABRICS. [Chap. XI. After "printing" and " drying " follows the so-called " ageing " process, which consists in exposing the printed goods in a more or less open or loose condition to an atmosphere of suitable temperature and hygroscopic state. The process has been made continuous by using the so-called " ageing machine," which is in reality a large chamber specially heated to 32 '^ — 38° C, and into which steam is admitted, so that a wet-bulb thermometer registers 4° — 6° G. lower. The printed calico is drawn through this chamber, under and over a system of hori- zontal rollers situated at the top and bottom, at such a rate that the calico is exposed to the moist warm atmosphere for about twenty to thirty minutes. During this operation the starch, or other thickening, is more or less softened by the moisture, and the mordant permeates the fibres more thoroughly ; large quantities of acetic acid are driven off, and a considerable amount of insoluble basic salt is fixed upon the cotton. Immediately on leaving this chamber the pieces are rolled up into loose bundles, and are allowed to remain for some time (twenty-four to forty-eight hours) in a warm room (32 '^ C, dry bulb, 28° C, wet bulb) for the completion of the ageing process. The next operation is that of " cleansing," or " dunging," in which the pieces are passed in the open width, for two minutes, through hot solutions con- taining one or more of the following ingredients : cow- dung, arsenate of soda, phosphate of soda, silicate of soda, chalk, ttc. The object of this cleansing operation is threefold : first, to fix more completely on the fibre that portion of the mordant which has escaped the action of the ageing process; secondly, to prevent the unprinted (unmordanted) portions of the cloth from becoming mordanted, and thus subsequently soiled, by reason of soluble mordant coming ofl" the printed parts; and, lastly, to remove the thickening. The last object is more thorouglily attained by repeating the cleansing operation, but this Chap, SI.] ALUMINIUM MORDAXTS. 171 time submitting the calico in the chain form to an intermittent and protracted process of squeezing between rollers. The most eflfectual method, however, of removing the thickening is to steep the cloth for an hour or two in an infusion of bran, the diastase ferment of which soon changes the insoluble starch into soluble glucose. After a thorough washing, the printed (mordanted) cloth is ready for dyeing. Aluminium acetates are largely used in many of the so-called steam-colours of the calico-printers, e.g.^ steam- alizarin - reds, &c. In the "colour," or thickened j)rinting mixture, the aluminium acetate is merely me- chanically mixed with the alizarin or other colouring matter ; but when the printed material is subjected to the action of steam, decomposition of the mordant, its combination with the colouring matter, and the fixing on the fibre of the coloured compound produced, all take place simultaneously. Experiment has shown that a pure aluminium acetate does not give such full rich colours as when a portion of the acetic acid is replaced by sulphuric, nitric^ hydro- chloric or hydrothiocyanic acid. An aluminium sulphate-acetate represented by the formula Al2(S04)(C2H30o)3(OH) seems to give the best results. Aluminium acetates, ttc, are also frequently used by the Turkey -red dyer to replace entirely, or in part only, the basic aluminium sulphates. No difference is made in the method of fixing from that usually adopted. By the ordinary cotton-dyer these mordants are comparatively little employed, since, in the general method adopted of fixing by precipitation, they possess no advantage over the basic sulphates, and are more costly. Sometimes they are used in conjunction with certain aniline colours. The cotton is worked in the colour solution, containing a certain proportion of aluminium acetate. During the gradual raising of the temperature 172 DYEIXG OF TEXTILE FABRICS. [Chap. XL of the bath, alumina is precipitated upon the fibre, and di'ags down along with it some colouring matter. The method does not yield fast dyes, and is in most cases ii'rational. 103. Application to Wool. — The aluminium acetates find no use in the mordanting of wool ; they are too sensitive, and, consequently, deposit the mordant . too much upon the surface of the fibre, making the wool harsh, and giving uneven colours. 104. Application to sSilk. — The aluminium acetates are little used in mordanting silk, except in printing. 105. Aluminium Thiocyanate (Sulphocyanide). — This mordant is of comparatively recent introduction. It is prepared by the double decomposition of alumi- nium sulphate, with barium or calcium thiocyanate, Al2(SOJs-18H.O-l-3[Ba(CXS\-2H..O] = Ai,(CXS)6 -i- SBaSO^ Almnmium Barinm Aliimininiu Barium sulphate. thiocyanate. thiocranate. sulphate. + 24H..O Water. Laulier and Hausmann give the following method of prepai'ation : Dissohe five kilogi'ams of aluminium sul- phate in five liti^s of boiling water, add 250 gi^ms of chalk, and then eleven and a half litres of crude cal- cium thiocyanate solution, 30^ Tw. (Sp. Gr. 1"15), and stir well; let settle, filter, and use the clear solution. It can be concentrated by boiling down, ad libitum, if necessary, since it is not decomposed in this manner. Solutions of basic thiocyanates may be prepared by adding varying amoimts of an alkiiline carbonate to solutions of the normal salt. Solutions of the following have been prepared bv Liechti and Suida : Alo(CXS).(OH), Al2(CXS),(0H).3 AL,(CXS),(0H)3, AL.(CXS),(OH),. With the exception of the fii-st, solutions of all these basic salts precipitate on boiling, and increase of basicity renders the decomposition more complete. IvTone are dissociated by merely diluting water. Chap.XI.J ALUMINIUM MORDANTS. 173 Normal alummmm thiocyanate has hitherto ^ only found use with the calico-printer for the production of steam alizarin reds. Its gi'eat advantage is, that not being an acid mordant (like the acetates which it replaces), it does not attack the steel "doctors"; the printing-colour remains, therefore, free from iron, and the ultimate colour is more certain of being clear and bright. Its high price has prevented it from being adopted in mordanting wool. It is, however, capable of giving good results. The wool simply requires to be introduced into a cold solution of the thiocyanate, which is then gradually heated to the boiling point in the course of 1 — IJ hours. . . There are no records of the employment of aluminium thiocyanate for silk. 106. Aluminium Chloride.— The normal salt, Al.Cle, may be prepared by the double decomposition of barium- or calcium-chloride and aluminium sulphate, or by dis- solving aluminium hydrate in hydrochloric acid. Solu- tions of basic salts may be prepared by adding the requi- site amount of alkaline carbonate to a solution of the normal salt. The following basic salts have been prepared in solu- tion : Al,Cl5(0H), A1,C1,(0H)„ Am3(OH)3, ALC1,(0H),. None of these mordants are precipitated, either by heating or by diluting with water. The first two of the above basic salts may also be made by dissolving aluminium hydrate in a hot solution of the normal salt, but if more A1,(0H), be added— e.^., suffi- cient to form thebasicsalt Al,Clo(0H)4— not only does it not dissolve, but the precipitate increases, and the filtered solution contains equal molecules of the normal salt and of hydrochloric acid. It would appear as if the nascent ALClo(OH)i had decomposed, according to the following equation : — 7Al2Clo(OH)4 -f 2H2O =5 Al2(0H)e -f 2Alfl, + 2 HCl BasiAlurainium AlumiBium Almmmum Hy^ochlonc chloride. hydrate. chloride. acid. 174 DYEING OP TEXTILE FABRICS. [Chap. XI. An aluminium chloi'ide-acetate, Al2Cl2(CoH302)4, may be prepared according to the following equation : Al3(S04)3-18H20+2[Pb(aH302)2-3HoO]+BaCl2=Al2Clo(C2H302)4 Aluminiura Leal " Barium A.luminium sulphate. acetate. chloride, chloride-acetate. +BaS04+2PbS04+24H20 Barium Lead Water, sulphate, sulphate. This mordant dissociates neither on heating nor on diluting with water, and yields to the cotton fibre, by steeping and drying, a remarkably low percentage of alumina, yet it is said to give excellent results in steam- alizarin-reds (calico-printing). The aluminium chlorides are seldom used as mor- dants. 107. Aluminium Nitrate. — The normal salt Al2(N03)g is prepared by the double decomposition of aluminium sulphate and lead nitrate, or by dissolving the requisite amount of aluminium hydrate in nitric acid. Basic mordants are prepared by adding an alkaline carbonate to a solution of the normal salt. None of these are dissociated, either by heating or by diluting with water. Aluminium nitrate is not much employed as a mor- dant. It finds a limited use in the production of yellow shades of steam - alizarin - reds, and some other steam colours. In mordanting wool or silk it is not used. 108. Aluminium Oxalate and Tartrate. — These mordants may be prepared by dissolving aluminium hydrate in the respective acids. As such, they find only a limited use in certain steam colours of the calico- printer. Although not used directly in mordanting wool, it is very probable that whenever potassium hydrogen tartrate (cream of tartar) is used along with aluminium sulphate, there is produced aluminium tartrate, which may be considered as the real mordanting salt. In mordanting silk these salts are not used. Chap. XI.] ALUMINIUM MORDANTS. 175 109. Aluminium Thiosulphate (Hyposulphite). — This mordant may be prepared by the double decompo- sition of aluminium sulphate and calcium thiosulphate (CaSoOg). Its use was proposed long ago by Kopp, who claimed for it the following advantages, that it was cheaper than aluminium acetate, gave fuller colours, fixed alumina on the fibre better, and prevented the fixing of iron, i.e., prevented its oxidation. Although capable of being used instead of aluminium acetate for dyed-alizarin- reds by the calico-printer, its employment has scarcely passed the experimental stage. Quite recently, liowever, a solution containing alum and sodium thiosulphate has been proposed for mordanting silk previous to dyeing with Alizarin, Alizarin Blue, Ccerulem, &c., and it is said to have yielded good results on the large scale. 110. Aluminate of Soda (AloNaoO^). — This mordant, also called " alkaline-pink mordant," is best prepared by dissolving aluminium hydrate in caustic soda to the point of saturation. Another method is to add caustic potash to a hot solution of aluminium sulphate, until the precipitate at first formed is exactly re-dissolved ; on cool- ing, most of the potassium sulphate crystallises out; Ox heat together, for example, 350 grams of aluminium sul- phate and 1 litre of caustic potash, 54° T\v. (Sp. Gr. 1-27), and cool, in order to allow the potassium sulphate to crystallise out. The solution thus obtained stands at 30° to 36° Tw. (Sp. Gr. M5— M8). Slight excess of alkali renders the solution more stable, and is not injurious. This mordant finds only a very limited use in calico- printing. It is thickened with dextrin. Its advantages are that it is not liable either to yield bad colours through being dried on the fibre at too high > a temperature, or to contract iron stains. Its chief defect is that it cannot be associated with acid mordants. After printing and drying, the alumina is fixed on the fibre by mere exposure to the atmospheric carbonic acid, or by passing the printed cloth, for two minutes, through a solution of ammonium chloride 10° Tw. 176 DTEIXG OF TEXTILE FABlll€& (CSiap. XL (Sp. Gt. I'Oo), heated to 50* — 60° C. Excessive accu- mulation of ammonia in the bath should be avoided, since it is apt to dissolve some of the alumina from the doth. Zinc sulphate or chloride may replace ammonium chloride for fixing purposes, but it possesses no advan- Aluminate of soda, owing to its alkalinity, is not used as a mordant for wool and silk. mas MORDASTBL These are scarcely less important than the aluminium mordants, being used for all fibres ; they may also claim equal antiquity. Unlike the aluminitun mordants, those of iron may occur in two states of oxidation, namely, as /errous and as ferric salts. m. Ferrous Snlphate (FeSO^-THjOj.— This mor- dant is also known as ^reen vitriol or copperag. It is largely prepared by dissolving scrap-iron in dilute sulphuric acid, and allowing the solution to crystallise ; also by the natural oxidation of iron pvrites, and as a by-product in the manufacture of alum and copper sulphate. When exposed to the air, the pale-green ci^^tals gradually become coated with brown, insoluble, basic ferric sulphate. Large crystals are apt to enclose mechanically some of the acid mother-liquor. The presence of copper and alumina is to be avoided. A solution of ferrous sulphate is not precipitated either by heating or by diluting with water, if access of ail- be prevented. AppIicaHon of Ferrous Sulphate to the various Textile Fibres. 112. Application to Cotton. — The employment of ferrous .sulphate, as such, in mordanting cotton is some- what limited. When used, it is generally applied as a "saddening" agent, Le., after the application of the colouring matter, in which case it forms a lake with CThap. XI.l IRON MORDANTS. 177 whatever colourmg matter the cotton has absorbed. After boiling the cotton with a decoction of the colouring matter, excess of the liquor is wrung out, and the cotton is then worked in a cold solution of ferrous sulphate. The process may be repeated. This mode of procedure is somewhat irrational, because the amount of colouring matter which unmordanted cotton absorbs is, as a rule, very small; hence the method is suitable only for very pale shades. A better method of employing this mordant is to im- pregnate the cotton with tannin matter, and afterwards steep it in a solution of ferrous sulphate, but for tliis mode of dyeing the ferric salt is preferable. Ferrous sulphate is used for the production of iron buffs on cotton in the same manner as ferric nitrate [see p. 191). It is also used for saddening or darkening the colours yielded by certain coal-tar colouring matters which have been fixed by means of tannic acid. 113. A Implication to Wool. — Ferrous sulphate is still used as a mordant in wool dyeing, but it has been very largely displaced by j^otassium dichromate. Although it is quite possible to mordant wool by boiling it with a mixture of ferrous sulphate and cream of tartar in suitable relative proportions, good bright colours are obtained only when a somewhat large amount of " tartar " is used, so that this method becomes costly. There is also the danger that the wool will be unevenly mordanted, unless great care is taken to raise the tempera- ture of the mordanting bath very gradually to the boiling point. Without the addition of " tartar," the wool acquires a deep reddish-brown colour, through precipita- tion of ferric oxide, or a basic sulphate ; ivith the addition, the wool acquires a pale yellowish colour. The most generally adopted method of applying ferrous sulphate is, first to boil the wool with a decoction of the colouring matter until a sutficient amount has been absorbed, and then to add ferrous sulphate to uhe 8ame bath, in the proportion of 5 — 8 per cent, of the M 178 DYEING OF TEXTILE FABRICS. [Chap. XI. weight of woo], and to continue the boiling for half an hour or so longer (saddening). With some colouring matters — e.g.^ Camwood and Catechu — the boiling with feri'ous sulphate is best per- formed in a separate bath. 114. Application to Silk. — FeiTous sulphate, as such, is not much used in mordantinor silk. In the d veins: of English black {noir Anglais)^ the silk is mordanted by working it at 60^ C. in a bath containing a solution of 50 per cent. Loswood, 50 per cent. Old Fustic, 5 — 6 per cent, ferrous sulphate, and 2 — 3 per cent, acetate of copper. It is afterwards dyed in a bath of Logwood and soap. (.S'ff also p. 333.) 115. Ferrous Acetate. — Tliis mordant may be pre- pared by the double decomposition of ferrous sulphate and lead or calcium acetate. The solution thus obtained does not keep well; it rapidly becomes oxidised, basic ferric acetate being deposited- FeSOi + CalCJEsOa). = Fe^C,H.0o)2 + CaS04. FeiTOtis Calciam Ferrous Calcium sulphate. acetate. acetate. sulphate. A much more generally useful mordant, and one which is manufactured on an extensive scale, is the so-caX\.edi jyyrol ignite of iron^ iron liquor, or hlcuck liquor. It is prepared by saturating crude acetic acid, 4° — 8° Tw. ^Sp. Gr. 1-02 — 104), (pyroligneous acid), with iron turnings, until the dark oKve liquid stands at about 20' Tw. (Sp. Gr. 1"1.); sometimes it is concentrated to 30' Tw. This mordant is generally understood to be a crude ferrous acetate, containing a certain amount of tany matter, which prevents it from oxidising rapidly. According to Moyret, however, it is a mixture of the ferrous salt with a salt of Fe^O^ (magnetic oxide), and he considers that to the presence of this latter its good qualities are due. Moyret further maintains that it does not necessarily contain tarry matter, but pyrocatechin, C6lI^(OHj2, the Clmp. XT.] IRON MORPAXTS. 179 iron salt of which is dark green, and he attributes the slowness of oxidation of the mordant to the presence of this reducing agrent. 116. Application to Cotton. — Pyrolignite of iron is the iron mordant most largely used by the calico-printer for dyeing blacks, purples, chocolates, &c. The mode of fixing by "ageing " and " cleansing " is identical with that employed with the aluminium acetates {see p. 169). To obtain the best results, the mordant must be applied to the calico as much as possible in the ferrous state. During the ageing process, a variable proportion of acetic acid escapes, but it is accompanied by oxidation of the remaining compound, and care must be taken that this latter does not proceed too rapidly or continue too long. If the oxidation were effected rapidly — e.g., by steaming, or by passing through solutions of potassium dichromate. or bleach in g-powder — the results would be unsatisfactory. According to Schlumberger, the normal state of oxidation for gooa results is that intermediate between ferrous and ferric oxide. Various additions have been made to this iron mordant, with a view to retard and render incomplete, or to make more regular, its oxidation during " ageing " ; that which has found most favour is arsenious acid, either dissolved in a mixture of acetic acid and common salt or ammonium chloride, or in the form of sodium arsenite. Since glyce- rine acts in the same way, a solution of arsenious acid in glycerine would probably be an excellent addition. Such solutions have received the name of " purple fixing liquors," or simply " fixing liquors," since they are almost invariably mixed with the mordant by the calico-printer for the production of dyed alizarin-purples. Iron liquor at about 6° Tw. (Sp. Gr. 1 -03), properly applied to calico gives a black on dyeing with Alizarin ; from 4° Tw. (Sp. Gr. 1-02) downwards to a very diluted state, it yields various shades of purple or lilac ; mixed with red liquor, and dyed subsequently with Garancina 180 DYEING OF TEXTILE FABRICS. [Chap. XI. or Alizarin, with the addition of Sumax^h and Quercitron Bark, it gives chocolate colours. Pjrolignite of iron is not extensively used by the general cotton-dyer, principally because it is more ex- pensive than the "nitrate of iron " usually employed, and because in many cases it yields only slightly better results. It is best applied by impregnating the cotton with a solution of tannin matter of suitable concentration ; after removing excess of liquid by squeezing, the cotton is worked and steeped in a cold solution of the iron mor- dant at 2°— 6° Tw. (Sp. Gr. 1-01— 1-03) for one hour or more, and finally washed. The concentration of the tannin bath determines the amount of iron fixed on the cotton. Since iron mordants are invariably used for the production of dark, dull, or sad colours, this method of fixing them by means of tannin tends to save colouring matter, because the dark colour of the tannate of iron is added to that of the colour subsequently imparted. 117. Application to JJ^ool. — Pyrolignite of ii'on is not employed in wool dyeing, though it might possibly be used with advantage in some cases — e.g., in the black dyeing of skin mats, «tc. — where only low temperatures in the baths are admissible. A mixture of ferrous sul- phate and sodium acetate might be used instead of the pyrolignite. 118. AppUcatioJi to SilJc. — Pyrolignite of iron is largely employed in the black dyeing and weio:hting of raw-silk fringes, (tc. ; its application is always preceded by a tannin bath. The silk is first impregnated at 40® — 45° C, witli an infusion of tannin matter, 100 per cent, (preferably chestnut extract), then worked at 50" — 60" C. in a bath of pyrolignite of iron (Fr. pied defer) 12° — 14° Tw. (Sp. Gr. 1 06 — 1 07), and finally exposed to the air. These opera- tions may be repeated from two to fifteen times, both to give body of colour and to add weight, which latter may vary from 30 to 400 per cent, of the weight of the silk. The mordanting bath is maintained at the requisite degree Chap. XI.] IROX MORDANTS. 181 of concentration by fresh additions of pyrolignite of iron ; its acidity, which increases with use, is neutralised by occasionally adding iron turnings, and heating the bath to near the boiling point. Too frequent use of the bath must be avoided, in order to give the added iron time to dissolve. The scum produced in heating must be removed. Pyrolignite of iron gives a bluish-black difficult to obtain by using other iron salts. The blue tone seems to be acquired through oxidation, and since the rate at which this proceeds depends upon many factors, the colour is very liable to be irregular. Although pyrolignite of iron has been employed in the above manner for boiled-oflf silk, it is now entirely replaced for this, by basic ferric sulphate (nitrate of iron). Sometimes a weak pyrolignite of iron bath is em- l)loyed in black silk dyeing, between two catechu baths, in order to alter the tone of colour. 119. Ferrous Nitrate and Ferrous Chloride do not seem to have been generally adopted as mordants. The latter is used under the name of " muriate of ii'on," in the pre- l)aration of a logwood black printing colour for woollens. 120. Ferrous Thiosulphate (Hyposulphite) has been recommended as a good iron mordant for cotton, but it has not been adopted in practice. It is produced by the double decomposition of ferrous sulphate and calcium thiosulphate. When dried on the fibre, it decomposes with final production of basic ferric sulphate. 121. Ferric Sulphate. "Nitrate of iron." — A solu- tion of normal ferric sulphate Fe, (S04)3 may be prepared according to the following equation : — 6FeS04-7H20 + 3H2SO4 + 2HX03 = 3Fe2(S04)3 + 2N0 + 46H2O Ferrous Sulphuric Nitric Ferric Nitrogen Water, sulphate. acid. acid, sulphate, dioxide. The ferrous sulphate is dissolved in water containing the calculated amount of sulphuric acid, the solution is gently heated and the necessary quantity of nitric acid is added gradually. If the solution is sufficiently concen- trated it may be boiled in order to complete the reaction. 182 DYEING OF TEXTILE FABRICS. [Chap. XL The nitric acid merelv acts as an oxidising agent, thus :- 2HXO3 = H2O + 2X0 + O3 hence the usual name given to this preparation, " niti-ate of ii'on," is a misnomer. Bv adding an alkaline carbonate to solutions of the normal salt of suitable concentration, it is possible to ob- tain solutions of basic ferric sulphates, e.g., Feo(S04)o(0H )^ and re^(SO,)3(OH)6, both of which, however, readily decompose on standing for a few hours. A soluble basic sulphate of greater stability is pre- pared by adding a suitable amount of hydrated ferric oxide to a solution of the normal salt. It is, however, more economical to adopt the method described for the normal salt, but using only half the amount of sulphuric acid, thus : — 12reS04-7a,0 + 3H,S04 + 4HXO3 = 3Fe4(S04^5(OH)2 + Ferrous ' Sulphuric Citric Bi sic ferric sulphate. acid. acid. sulphate. + 86H.O + 4X0 Water. Xitrosren dioxide. In making this preparation on a small scale, it will be noticed that at Urst, even after the whole of the requisite nitric acid has been added, the solution has a dirty olive-brown colour, which is indicative of the presence of ferrous salt. When, however, the boiling liquid has attained a certain degi'ee of concentration, complete oxidation suddenly takes place, there is a copious evolu- tion of red fumes, and the liquid at once assumes the normal orange yellow colour of the ferric salt solution. This basic ferric sulphate (Fr. rouUle) is sold very largely to black silk-dyers, as a deep red liquid of about 70-— 85° Tw. (Sp. Gr/l-35 — 1-4). It is made in large covered stone vats pro%'ided with a wide tube for the dis- engagement of the nitrous fumes, a small tube for the introduction of the acids, and a large opening for intro- Chap. XI.J IRON MORDANTS, 183 ducing the ferrous sulphate, and stirring the mixture. For every 100 kilos, of basic sulphate at 84° Tw. (Sp. Gr. 1*42) required, 80 kilos, of ferrous sulphate are employed ; these are put into the vat, and a mixture, slightly diluted with water, containing 10 — 15 per cent, of nitric acid 72° Tw., and 6 — 7 per cent, of sulphuric acid 168° Tw., is run in gradually. The whole is well stirred, and the reaction is allowed to proceed in the cold ; when this primary reaction has subsided it is completed by blow- ing in steam. The nitrous fumes, which are given oflf in large quantities, are condensed and collected. When no more are evolved, the reaction is complete, and the liquid is transferred to large tanks to cool and settle. It was formerly thought that the presence of small proportions of ferrous sulphate and nitric acid were bene- ficial in the production of the best black on silk, but this was a mistake. A good sample of this mordant should not be precipitated by silver nitrate. Potassium ferricyanide should, with a dilute solution, give at most a blue colora- tion, but no precipitate. Submitted to desiccation and calcining, it should leave about 17 per cent, ferric oxide. It is dissociated by diluting with water, an insoluble and still more basic ferric sulphate being precipitated, while a more acid salt remains in solution. Since it sometimes happens that two preparations having the same chemical composition give different results in dyeing, it is su])posed that there are isomeric compounds due to the different temperatures at which the oxidation may take place. Great care is required in its manufacture, since if it is too basic it tarnishes the lustre of the silk, and if too acid it does not give up its oxide to the fibre in sufficient quantity. 122, Application to Cotton. — The normal ferric sul- phate is seldom used. The above-mentioned soluble basic ferric sulphate, or even a slightly more acid compoimd, is used in dyeing cotton black. The cotton is first impregnated with an 184 DYEIXG OF TEXTILE FABRICS. [Chap XI. infusion of tannin matter, and either at once, or after pass- ing through lime-water, it is worked and steeped for about one hour in a solution of the mordant, at a strength of 2=_4= Tw. (Sp. Gr. 1 01— 1-02). It is finally washed, either in water only, or in such as contains a small addi- tion of ground chalk, for the purpose of completing the precipitation of basic salt on the lib re. and to remove aU acidity. The cotton is subsequently dyed in a logwood bath. In this process the tannic acid, which is absorbed and atti*acted by the cotton, serves principally to fijx the iron mordant, although it incidentally produces a bluish-black colour by combining with the ferric oxide or basic feiTic salt. The passing through lime-water after the tannin bath e^'idently forms a calcium tannate, and the decomposition of the ferric salt is thereby facilitated, since the lime combines with its sulphuric acid. This mordant may also be used for dyeing iron bulls in the same way as ferric nitrate (see p. 191). 123. Application to Wool. — The ferric sulphates do not appear to have been utilised hitherto in the mordant- ing of wool, although it seems possible that they might be usefid if properly applied 124. Application to Silk. — The soluble basic ferric sulphate Fe^(S0^)5(0H), is the ii'on mordant par excel- lence of the black-silk dyer. In mordanting raw silk, the latter is first worked in a tepid bath (40^ — 50' C.) of sodium carbonate, washed and well wiiing out, and then worked in a cold solu- tion of the mordant at lo** Tw. (Sp. Gr. 1'075) for ^ — 1 hour. The silk is then drained, wrung out, well washed, wrung out again, and worked for ah)Out half an hour in a tepid (40= — .56-0.) solution of sodium carbonate. It is finallv wrung: out and well washed. These several operations may be repeated three or four times, accoi-ding to the colour and weight required In mordanting boiled-olf silk, the material is worked for ^ — 1 hour in a cold solution of the basic ferric Chap. XI.l IRON MORDANTS. 185 sulphate at about 50*^ Tw. (Sp. Gr. 1"25), excess of liquid Ls then removed by squeezing and wringing, and the silk is well washed — first with cold water, and finally with tepid water. These operations may be repeated as many as seven or eight times, after which the silk is worked at 100° C, in an old soap-bath, or one containing "boiled-off" liquor, to which about 12 per cent, (of the weight of silk) of olein soap and 2 per cent, of sodium carbonate crystals are added. A final washing completes the mordanting process. The iron and soap baths are permanent, care being taken^ by making fresh additions of mordant, to maintain regularly the concentration of the former, and to boil up the latter before mordanting each lot of silk, in order to bring to the surface and then skim off* the iron soap which has been formed during a previous operation. It is essential that silk mordanted in basic ferric sulphate should not be allowed to dry in the mordanted state. It should either be left steeping in the strong mordant, or left, after washing, well covered up with wet sheets. Silk strongly impregnated with ferric oxide is gradually destroyed on keeping, slow coml:»ustion or oxi- dation of the fibre being induced. The theory relative to the above methods of mordant- ing is as follows : — In the case of raw silk, where a comparatively weak solution of the ferric sulphate is employed, apart fiom general absorption of the liquid, the silk-gum itself causes decomposition and precipitation of an insoluble basic salt throughout its mass during the steeping oj)eration. The washing in water, and rinsing in sodium carbonate, complete the decomposition, and remove the necessarily liberated acid salt. In the case of boiled-off* silk, the fibre simply ab- sorbs the liquid during the steeping in the concentrated solution of mordant, decomposition and precipitation of basic salt only taking place during the washing process, 186 ^iW Chap. XI.] IRON MORDANTS. 187 which, of course, also removes the acid salt formed. The employment of water containing bicarbonate of lime is exceedingly advantageous for the washing, since it greatly facilitates the decomposition of the absorbed mordant. The boiling in soap solution is necessary to complete the decomposition of the absorbed mordant, and the Fig. 46.— Squeezing Machine used in the Mordanting of Silk. temperature employed, 100° C, is said to modify the pre- cipitated ferric oxide and render it less liable to dissolve in the successive iron baths. According to Moyret, no iron soap is precipitated on the silk in this operation. Previous impregnation of the silk with tannin matter does not tend to cause a larger precipitation of mordant on the fibre, but rather the reverse ; indeed, the silk loses weight through the oxidation and destruction of the absorbed tannic acid. 188 DYEING OF TEXTILE FABRICS. [Chap. XT.. By one complete mordanting operation the silk gains about 4 per cent, in weight. If the operations are repeated six times, it gains about 25 per cent., or has about made up the loss sustained in boiling-off. If repeated seven to eight times, there is a gain of about 8 per cent, of the original weight of the raw silk. Thus mordanted, the silk possesses a deep orange brown colour, and still retains its lustre. Fig. 45 represents the mordanting bath in general use with black silk dyers. It consists of a rectangular wooden vat, for holding the iron mordant. The silk, properly suspended on smooth wooden rods {e.g., hickory sticks with the bark l>eeled off), is turned in the solution by hand. After draining, the excess of liquid is removed by passing the hanks singly through a squeezing machme (Fig. 46), provided with an Lnclined, broad, endless band of india- rubber, A, which carries tlie hanks laid thereon through the india-rubber rollers. By means of the screws at B the endless band. A, can always be kept in a state of proper tension. A more complete expression of the liquid is effected afterwards by twisting the hanks vigorously by hand. The washing machine employed is illustrated in Fig. 47, which represents one constructed by Gebriider Wansleben, of Crefeld. It consists of a double row of glazed, fluted, porcelain reels, on which the hanks of silk are suspended and made to re\'olve. The reels are geared together by a series of cog-wheels, one of which, on each side, is driven by a cog-wheel attached to a central friction disc. The washing is effected by water-pipes, situated below the reels, and perforated on both sides horizontally. A similar water-pipe is situated between each pair of hanks, so tliat each one during its revolution has a continuous and uninterrupted stream of water-jets playing upon it, both internally and externally. In order to prevent the fibres from becoming en- 189 190 DYEING OF TEXTILE FABRICS. [Chap. XI. tangled, the reels are automatically caused to revolve alternately to the right and left. The movement of a single lever sets the reels in motion, and turns on the "water. The reels on each side can be worked indepen- dently of each other, so that while one set are in action and washing, the other can be emptied of hanks and refilled. After washing with cold wat^r in the above manner, an additional washinsr or rinsinor with warm water is etfected in a wooden trough, situated between and below the two sets of reels. By means of a coimt-er- poise, it can be readily brought below either set of hanks, so that they may then revolve in the warm water. The trough is fed from a tank placed at a higher level, where the water is specially heated by steam to the requisite temperature. 125. Ferric Nitrate-sulphates. — Several of these arc made and employed in pra. 1 SI, 182), but the sulphuric acid which was there added is here entirely or pfe.rtially replaced by nitric acid, thus : — 6FeS04-7HoO + eHXCg + 2HXO3 = ^'^^^^'^O^j.^SO^':.^ -|- Ferrous sulphate. Kitric acid. rerric-nitrate^salphate. + 2N0 + 46H2O Nitrogen dioxide 12FeS04-7H20 + GHIN'Og + 4HNO3 = ^'Fe^'^0^j:S0^40^)i -f- Basic-ferric-nitrate-sulphate. + 4N0 + 86n„0 The composition of those used in practice is very variable. Compounds of definite composition are not '^lerally intended to be made, and their value as mor- its is entirely determined by the results they yield in dyeing. They are deep brownish-red solutions, and contain Chap, XI. J IRON MORDANTS. 191 frequently some ferrous salt which has escaped oxidation, and whicJi, in many cases, is not considered injurious. In conjunction with Logwood, for example, pure ferric salts tend to give brownish-blacks, while the ferrous salts orive bluish-blacks. A mixture of the two is there- fore considered to give a more pleasing jet-black. Excess of acid should be avoided when these mor- dants are applied to cotton, especially in printing colours which require steaming. If used for purposes of " saddening," a slight acidity may, oii the other hand, be beneficial, since the mordant is then more slowly decomposed, and more likely to penetrate the fibre and to give a regular mordanting. If too basic, on the contrary, the mordant is too sensitive, decomposes spontaneously, and gives irregular work. 126. Application. — The principal application of the nitrate-sulphates of iron is in the black dyeing of cotton. The mode of application is identical with that given for the ferric sulphates. (See p. 183.) In wool dyeing, the above mordants are not used, and in silk dyeing they have been supplanted by the soluble basic ferric sulphate. 127. Ferric Nitrate. — This mordant constitutes the true nitrate of iron of the dyer, and is prepared by dissolving scrap-iron slowly in nitric acid. As soon as there is a sensible deposit of insoluble basic ferric nitrate the addition of iron is discontinued, and the liquid is allowed to settle. According to the proportion of nitric acid used, and the care taken in the preparation, the composition will be very variable. It finds a comparatively limited use now, being em- ployed only in cotton dyeing, e.g., in the production of buff shades. The cotton is impregnated with a solution of nitrate of iron, and, after removing excess, is passed through a cold solution of sodium carbonate, wlj/jK-eby ferric oxide is precipitated. It is also used occasionally for blacks. 128. Ferric Acetate.— The normal acetate, Fe2(C2H302)6, 192 DYEING OF TEXTILE FABRICS. [Chap XI. is prepared by the double decomposition of ferric sul- phate and lead acetate, in suitable proportions. On neutralising a solution of the normal acetate ■with increasing amounts of an alkaline carbonate, solu- tions of various basic acetates are obtained, e.q.^ re2(C.H30o),(OH), re,(aH30,),(0H)., Fe.(aH30.,)3(OH)3; Feo(C.HoO.)o(OH)4. A solution of the normal salt is not dissociated either by heating or diluting -srith water ; solutions of the basic salts are, however, dissociated on heating, but not by dilution. Increase of basicity lowei"^ the dissociation temperature. It is remarkable, howe^'er, that when the solutions are diluted, the point of disso- ciation by heating is raised in the least basic mordant, Feo(CoH30o)5(OH), remains unchanged in the case of Feo(CoH302)4(OH)o, and is lowered only in the more basic mordants. (Liechti and Suida.) 129. Applicatio7i. — The ferric acetates seem to find, at present, little or no use as mordants, although some were formerly employed rather largely in black silk dyeing. 130. Ferric sulphate-acetates have occasionally been used, having been incidentally prepared through the desire of reducing the excessive acidity of ferric sulphates by the addition of lead acetate. 131. Ferric Acetate-Nitrate, or ferric nitrate-acetate. — This mordant has also been incidentally prepared by adding a certain proportion of lead acetate to solutions of certain ferric nitrate-sulphates with a view to reduce their acidity. A product of this nature has, however, been much used in silk dyeing, and is still employed in the dyeing of black silk intended for plush (e.g., for hats), since the colour which it yields is not afiected by hot- pressing or ironing. Its mode of preparation, for a long time ke])t secret, is as follows : iron turnings are dissolved in nitric acid, as in the manufacture of ferric nitrate, but the addition of iron is continued until the whole becomes a pasty mass of insoluble basic ferric nitrate. This basic precipitate is collected and dissolved in hot acetic acid, taking care to leave a slight excess of the Chap. XL] IRON MORDANTS. 193 precipitate. The deep red solution thus obtained is allowed to cool and settle. 132. Ferric Chloride. — The normal compound, 'Fe.JJ\, is not used as a mordant. Basic salts may be produced by dissolving hydrated ferric oxide in solutions of the normal salt, but these, too, have as yet found no use in practice. 133. Alkaline Iron Mordants. — Although hydrated ferric oxide is not soluble in caustic alkalis, the addition of certain organic substances (tartaric acid, glucose, glycerine, &c.) to the solution of a ferric salt, prevents the precipitation of the ferric oxide by alkali^ and hence an alkaline solution of iron can be thus obtained. Take, for example, 2^ litres of ferric sulphate solution, equiva- lent to 1,250 grams of ferrous sulphate, add 1 litre of glycerine and 10 litres of caustic soda, 70° Tw. (Sp. Gr. 1 '35) ; the solution has a deep reddish-brown colour. An alkaline ferric solution is also obtained by adding an excess of a concentrated potassium carbonate solu- tion to a concentrated solution of ferric sulphate or nitrate. The precipitate which at first forms is re-dis- solved under the above conditions. Pyrophosphate of iron, (Fe2)2(P207)3, is soluble in ammonia. Cotton mordanted by means of this alkaline solution is said to give good purples when dyed with Madder or Alizarin. It has been noticed by Burgemeister that an addition of glycerine to a solution of ferrous sulphate prevents the precipitation of oxide by alkali, and that this alka- line solution is capable of mordanting cotton. Mix, for example, 1 kilo of ferrous sulphate, 2 litres of glycerine, and 60 litres of caustic soda, 70*^ Tw. Notwithstanding the above facts, alkaline iron mor- dants have as yet received no practical application by the dyer, no doubt because of their excessive alkalinity and cost. 134. Iron Alum.— This salt, ^^ I (^0,), -2 4:11,0, is exactly analogous to ordinary alum, and may be applied N 194: DYEING OF TEXTILE FABRICS. [Chap. XL in the same way. Its use hitherto has been limited, having been confined to mordanting wool for dyeing with alizarin colours. There is no reason, however, why it should not find a more extended use. TIN MORDANTS. 135. Tin. — Tin may occur in two states of oxidation — as stannous oxide, SnO, and as stannic oxide, SnOo. These oxides, in their hydrated state, Sn(0H)2 and Sn(0H)4, are soluble either in acids or in caustic alkalis, and thus give rise to corresj^onding stannous and stannic salts, either of an acid or of an alkaline nature. Apart from their character as mordants, the stannous salts act as powerful reducing agents ; they have a great avidity for oxygen, and tend to change into stannic compounds. This fact should always be bome in mind by the textile colourist, since it sometimes excludes them from being used in conjunction with other mordants of an oxidising character, or with such colouring matters as are decolorised by a reducing action. In particular cases, however, this characteristic may be made to serve a useful purpose, for example, in the reduction of indigo-blue to indigo-white, the discharging of iron bufifej manganese browns, etc., in calico-printing. As a general rule, the stannous salts are employed for wool, and the stannic salts for cotton ; the coloui'^ they yield with polygenetic colouring matters are usually remarkable for their brilliancy. Solutions of the stannous and stannic salts are colour- less. Many of the tin solutions, however, which the dyer prepares by means of nitric acid, with or without the addition of hydrochloric acid or alkali chlorides, possess a very decided yellow colour, and they seem to be of a more unstable character than the ordinary compounds. Hence some consider that these represent solutions of tin in an intermediate state of oxidation, namely, as sesquioxide, SugOg. It is, however, more probable that this coloration and sensibility are due to Chap. XI.] TIN MORDANTS. 195 the presence of a peculiar modificatioii of stannic oxide called metastannic acid. 136. Stannous Chloride. — This mordant is sold in the crystalline form (SnClo*2 HoO) under the name of *Hin crystals" or "tin salt." A good sample should contain 52 per cent, of tin. It is prepared by dissolving granulated tin in hydrochloric acid with the aid of heat, and allowing the concentrated liquid to crystallise. Sn + 2HC1 4- 2H.p = !SnCl2-2H20 + H2 Access of air is said to facilitate solution, so that it may also be effected without heat if the acid is poured successively on exposed heaps of feathered tin. Sn + 2HC1 + 2HoO + = SnCl2-2H20 + H2O Very frequently the solution is not crystallised ; it is then sold under the names of "single muriate of tin" and " double muriate of tin," according as the Specific Gravity is 1-3 or 1-6 (60^ Tw. or 120'-" Tw.). These " muriates of tin " differ frequently, however, in concentration, from the standards here given ; the amounts of tin, and the free acid which they always contain, vary considerably, and can only be determined by analysis. They are occasionally subjected to adul- teration. " Tin crystals " dissolve in a small quantity of water without undergoing decomposition, and a clear solution is obtained ; on further dilution, however, this becomes turbid through the formation of an insoluble basic chloride or oxychloride [2Sn(OH)Cl-H20] which is pre- cipitated. 3SnCLj + 2H2O + =2Sn(OH)a-H20 -\- SnCl4 Basic stannous chloride. The precipitate re-dissolves on the addition of hydro- chloric acid. A similar oxidation takes place when ^' tin crystals " are kept for a lengthened period, especially if exposed to air and light Osving .to the presence 196 DYEIN'G OF TEXTILE FABRICS. [Chap. XL of excess of acid, the " muriates of tin " are less readily decomposed by dilurion with water. 137. Application to Cotton. — " Tin crystals " are largely used by the calico-printer for mixing with thickened aluminium mordants. When used in small amount, this addition prevents, probably by reason of its reducing action, the fixing of iron accidentally present in the printing colour, or acquired during the processes of printing, \ though contain- ing no aluminium 13 so called because its crystalline form 212 DYEING OF TEXTILE FABRICS. [Chap. XL and chemical constitution are similar to those of ordinary alum. It is obtained in large quantities as a by-product in the manufacture of artificial Alizarin from anthracene, in which case it contains calcium sulphate and organic matter as impurities. If necessary, it may be specially prepared by adding to a solution of bichromate of potash containing the requisite quantity of sulphuric acid, any substances readily oxidised, e.g., sulphurous acid, oxalic acid, alcohol, sugar, starch, glycerine, &c. The following equation represents generally the reaction which takes place : — KgCr^O^ + 4 (H2SO4) + I7H2O + 3H2 = [ ?2 I (S04)4-24H20] Potassium 2 ) dichromate. Clu-ome alum. The organic substances mentioned are added as rapidly as the violent reaction and effervescence will permit. The mixture becomes much heated, and care should always be taken not to allow it to cool, otherwise there is a possibility of the reaction ceasing, and external heat would then have to be applied. The following proportions of ingredients are employed by calico-printers : 100 grams of KoCr.,0;, 220 grams of water, 123 grams of H2SO4, 168° Tw' (Sp. Gr. 1-84), 24 grams of starch. When properly made, the solution should have a bluish-green colour ; if olive-green, it still contains undecomposed bichromate of potash. Since the liquid has been heated, crystallisation takes place with difficulty ; but, as a rule, after standing for a lengthened period, it deposits dark purple crystals. These dissolve in cold water, with a dirty bluish-violet colour, but if the solution be heated above 70° C, it acquires a green colour. On long standing the original colour returns. The violet solution contains the normal salt, whereas the green solution is said to contain a mixture of basic and acid salts. This explanation is simpler and better Chap. XL] CHROMIUM MORDANTS. 213 than that which supposes the existence of two modifica- tions of chromium hydrate. These violet and green solutions differ from each other in many of their reactions, e.g., barium chloride does not precipitate the whole of the sulphuric acid from the green solution at the ordinary temperature, whereas with the violet solution the decomposition is normal ; ammonia precipitates hydrated chromic oxide, Cr2(OH)6, from both solutions, but only that obtained from the violet solution is soluble in excess of ammonia. Similar diSerences are shown by other chromic salts. A normal chrome-alum solution is not decomposed either by heating or by dilution. By adding calculated amounts of an alkaline car- bonate or chromium hydrate to a solution of the normal chrome- alum, solutions containing basic chromium sul- phates are obtained, for example, such as are represented by the following formulae : — Cr„(S04)2(OH)2, Cr4(S04)3(OH)s, Cr2(SO,)(OH)4. Such solutions will, of course, contain also potassium and sodium sulphate. Unlike those of the corresponding aluminium compounds, they show no sign of dissociation on heating (Liechti and Suida). Dissociation by dilution is accelerated the more basic the salt is, e.g.., a solution containing Cr2(S04)o(OH)c must be diluted 85-fold before precipitation ensues, whereas Cro(SOJ (OH)^ requires only I'B-fold dilution; but in all cases the precipitation is not complete. The presence of sodium sulphate makes the solution less sensitive to dis- sociation by dilution. Parallel with these facts are those which refer to the behaviour of chrome-alum solutions to the fibre ; with increase of basicity a larger amount of chromic oxide is deposited on the fibre by the operations of impregnation, drying, and ageing. A solution of Twrmal chrome-alum containing 224*6 grams per litre {i.e., an amount equivalent to 150 grams of aluminium, sulphate per litre) deposits on the cotton fibre 214: DYEING OF TEXTILE FABRICS. [Chap. XL 1-8 per cent, of the chromic oxide presented to it, an equivalent solution of the basic chrome-alum containing Cr.^SO^(OH)^ (made from chrome-alum and sodium carbonate) gives up 87 '5 per cent, of the available chromic oxide. The presence of sodium sulphate in the solution hindei*s this deposition of mordant con- siderably. A solution of chrome-alum is precipitated on the ad- dition of sodium hydrate or ammonia, but the precipitate redissolves in an excess of the precipitant. The alkaline solutions thus obtained are precipitated on boiling. The precipitates caused by sodium carbonate, phosphate, and silicate are not redissolved in excess. The basic salt Cr^(S0^)3(0H)g behaves towards these reagents in a similar manner. It is remarkable that some of the basic sulphates are precipitated on the addi- tion of acetic acid or sodium acetate. The most basic salt solution obtainable by neutral- ising chrome -alum with sodium carbonate contains Cr,SO^(OH)^, thus : [K2Cr.:(S04:4-24H20] + 2X3X03 -\- 2K,0 = Cr,S04(0H^4 + Cliroiatt-alvun. Sodium Basic carbonate. chromium sulphate. + K2SO4 -I- 2^x•S04 -I- 2CO2 -f- 24H2O. The presence of sodium sulphate makes the solution less sensitive to dissociation by dilution. This retarding influence is already seen from the fact that the most basic salt obtainable by neuti^alising chrome-alum with sodium carbonate is CroSO^(OH)^, while if the chrome-alum is neuti-alised by adding chromic hydrate, the most basic salt obtainable is Cr^fSO^jofOH)^ (Liechti and Suida). 161. Chromium Sulphate [Cro( 804)3] °iay be prepared by dissolving hydrated chromic oxide in sulphuric acid. Violet and gi-een solutions exist. Basic salts are prepared bv neuti-alising solutions of the normal salt with chromic hydrate or sodium carbonate. The most basic salt which can be prepared by the latter means is Cr^(S0^)3(0H)g Chap. XL] CHROMIUM MORDANTS. 215 which decomposes spontaneously after standing for three months. 2Cr2(SO,)3 + SXasCOa + SHgO = Cr4(S04)3(OH)g + 3NaoSO, + Normal Sclium Basic So timn chromium carbonate. ckromium sulpliate. sulphate, sulphate. + 3CO2. With the use of chromic hydrate, the most basic salt obtainable is Cr2(S04)2(OH)2, thus : 2Cr2(S04)3 + Cr,(OH)e = 3Cr2(SO,)2(OHo). Chromic Basic hydrate. chromium sulphate. In the first case the neutralising can be pushed to a further limit because there the presence of the sodium sulphate tends to retard the dissociation of the basic salt. Neither of these is so basic as the solutions similarly obtained from chrome-aluni. Both the normal and the basic chromium sulphates behave in respect of dissociation by heating and by dilution, like the corresponding chrome- alum solutions ; the same may be said of their behaviour with sodium hydrate, ammonia, sodium carbonate, phos- phate, and silicate. A solution of normal chromium sulphate (equivalent to 224-6 grams of chrome-alum per litre) deposits 12-8 per cent, of the available CrjO.^ on the cotton fibre by the operations of impregnation, drying, and ageing ; an equi- valent solution of the basic salt Cr_^(S0.^)3(0H)g made from chromium sulphate and sodium carbonate yields to the fibre 86-4 per cent, of the available chromic oxide. Although these solutions of pure chromium sulphate cannot be made as basic as those of chrome-alum, they give up practically the same amount of chromium oxide to the fibre under the above conditions, because they are more sensitive (Liechti and Suida). 162. Chromium Acetate. — A solution of the normal salt [Cr.^(C,,H30,,)J may be prepared by mixing, in suitable proportions, solutions of lead acetate and chromium 216 DYEDfG OF TEXTILE FABRICS. [Chap. XL solDhate or chrome-alum ; in the latter case, of course, potassium sulphate is present. [^' I (S04)4-24H,0] 4- 3|Tb aH302\-3H20] = Cr^C^^Mt ^2 ] Jjead acetate. Ctiroininm Chrome alma. acetate. + 3PbS04 + K2SO4 + asHoO. It is both interesting and remarkable that a solution of normal chromium acetate, prepared as ab'cve indicated, is not dissociated on boiling, however much diluted the solution may be. It is not precipitated in the cold by caustic alkalis, alkaline carbonates, phosphates, and sili- cates, anunoniacal soap, or sulphated-oil solutions, but on hoUing with these additions, complete precipitation is effected. The duration of the boiling necessary to cause decomposition varies with the amount of dilution, and if the addition made be phosphate of soda, very long boiling is required (Liechti and Suida). A solution of pure chromium acetate can be evapo- rated to dryness, and be even heated to 230'' C, it is said, without losing its solubility. If a freshly prepared violet solution of normal chro- mium acetate be boiled, it becomes greenish- violet, and if basic salts are made from this by the addition of sodium carbonate, they soon decompose. A similar change takes place if a solution of the normal salt is kept for a long time ; it loses its violet colour, and is then readily precipi- tated by sodium carbonate on heating. Somewhat less sensitive basic mordants are obtained, if the sodium car- bonate is added in two poitions, and the liquid is gently heated after the first addition. On the contrary, if from a freshJy prepared violet solution of normal chromium acetate, basic solutions are made by adding sodium carbonate, such solutions retain the violet colour ; they may be kept for a long time, and may even be heated gradually to the boiling poiut with- out undergoing decomposition. If, however, after long keeping, a very slight further addition of sodium carbon- Chap. XI.] CHROMIUM MORDAXTS. 217 ate is made, complete decomposition takes place at once on boiling the solution. ^ Solutions of basic acetates may be obtained by makinli'Cerlj effective. In any case its mordanting power is by no means equal to that of an equivalent quantity of bichromate of potasL In those cases where the oxidising action of bichro- mate of potash acts injuriously upon the colouring matter employed, the use of chrome-alum in its stead might cer- tainly l>e recommended, but for the great majority of cases it has no advantages over its more successful rival. It is possible that some of the basic salts of chromium may mordant wool better than the normal ones, but it will Ije difficult for them to supplant bichromate of potash. 170. AppJi'Cation to Silk. — The chromium salts in which the chromium acts as a base have hitherto found little or no use in silk dyeing. They are, however, well wcnrtli the attention of the dyer. COPPER MORDAKTS. The use of copper salts as mordants is unimportant ; in most of the cases where they are employed by the textile colourist, they serve principally as oxidising agents. 171. CJopper Sulphate (CuS04-5H20) is manufac- tured in large quantities by roasting copper pyrites or other ores containing copper, and subs€?quently heating them with sulpliuric acid. Purification from iron is generally effected by first precipitating the whole of the copper from the impure solutions by means of iron, and then re-dissolving it in dilute sulphuric acid. To the dyer, copper sulphate is well known under the names " blue- vitriol," " blue-stone," p^h'-OH Chap. XI. I SULPHATED OIL. 235 When boiled with dilute caustic alkali, it decomposes with the production of insoluble oxyoleic acid, glycerine, and sulphuric acid. Its alkaline compound is soluble, but those of the alkaline earths and heavy metals are inso- luble ; they are readily obtained by mixing its aqueous or alkaline solutions with solutions of the metallic salts. The aluminium compound [Al4(042Hj.40i2S)3j is a white or slightly yellowish body. The substance which is insoluble in water but soluble in ether is oxyoleic acid (G^JiL^O^. It is readily soluble in alkaline water, forming a soapy liquid, which produces with solutions the salts of the alkaline earths, earths, and heavy metals, tarry or flocculent precipitates very soluble in ether. A secondary reaction seems also to take place, probably giving rise to the production of an intermediate and unstable ether derivative of oxystearic acid. This is decomposed during the washing with water, and produces sulphuric acid, and oxystearic-glycerine-sulphuric-ether (C42H82O12S) and oxystearic acid (OigHgeOg). 2(Ci8H3302)3C3H54-7H2S04+ 8H2O = C40H80O12S + 4C18H36O3 + Tri-olein. Oxystearic - Oxystearic glycerine-sul- acid, pliuric ether. + 6H2SO4. Castor oil consists essentially of the glycerine com- pound of ricinoleic acid, Ci8H3302"OH, and has the composi- tion C3H,(0-C,3H330,)3. If in the above reaction castor oil be substituted for olive oil, similar substances to those just mentioned are pro- duced, namely, trioxyoleic-glycerine-suli^huric-ether : — C42H780,6S, or SO^^J^^^^.^^ and trioxy oleic acid {Q^^^O^. The castor oil product is now a commercial article, and is sold, more or less diluted with water and neutralised 236 DYEIXG OF TEXTILE FABRICS. [Chap. XI. with caustic soda or ammonia, under the following names, TurJcey-red oil., alizarin oil, sulphatpA oil, soluble oil, &c. When properly made and perfectly neutralised or rendered slightly alkaline, it dissolves in distilled water, giving a perfectly clear solution. If the water contains lime, e ti-^ated of in *' Notes on Wool-Dveing " {see p. 276.) 216. Unspun Cotton Wool. — Dyeing Macldmry, — The dye-vessel employed for raw-cotton is similar to that described as being used for loose-wool {see p. 277). Direct fii'e heat is seldom or never adopted. In recent yeai*s various novel aiTangements have been proposed and patented, but their practicability has yet to be proved, e.g., vacuum- dyeing machines. Washing Machinery. — The washing of raw cotton may be effected by the raw-wool scouring machine {see p. JOO). Excess of water is removed by passing it between a pair of squeezing rollers, or by means of the centrifugal machine (hydro-extractor). Drying Machinery. — Raw cotton may be diied on the machines descril>ed as being used for loose-wool {see p. 277). 217. Cotton Yarn. — Dyeing Machinery . — For hank- dyeing the simplest method is to work the hanks in the dye liquor by hand in the manner described for woollen yajTi scouring on p. 105. With large quantities of any single colour, e.g., Turkey -red, logwood-black, indigo-blue, lirc, the employ- ment of dyeing machines becomes almost impemtive. Chap. Xn.] MACHINERY FOR COTTON YARN. 251 Figs, 48 and 49 represent an excellent machine, de- signed bv A. Wilson, of Paisley. It consists of an ordinary rectangular wooden dye- Z^l :;^ -{ ^^S- m '^i ^^m ■^ i^. ■m" ^ ----••• ■• -■ - . ~~ mm^^M^mmm^^ Fig. 48.— Hank-Djeiug Macliiue. vat fitted witli a four-armed skeleton-winch, upon which the rods, previously filled with yarn, can be readily suspended. In charging the ma- chine, the arm a is brought into the upright position, the movable portion B is lifted oflf the cross piece, and the hinged portion at c is turned back. The hanks of yarn are hung on pairs of light wooden rods ; - these are placed in the sockets at b and c, and then securely fastened down by replacing the movable portions alluded to. The winch is then turned round, and the other half is filled with hanks in a similar i—L Fig. 49. -Section of Fig. 48. ^52 DYEING OF TEXTILE FABRICfe. [Chap. XH. manner ; b represents the arrangement of sockets with movable caps in the central part of the -winch, D that at the ends where there are no movable parts, the ends of the rods being merely pushed into the sockets. When the dyeing is finished, the whole winch full of yam can be i-aised with a ti^avelling crane out of the dve-vat bv the rings e. and lowered into another vat for washing, 6:c. Another hank-dyeing machine, that of E. Boden, is Fig. 50.— Boden's Hiuik-Dveing Machine. represented in Fig. 50, the back portion only being exhibited. It consists of a wooden dyebeck, provided with a light iron frajne caiTving a series of reels a geared with each other at one end. The frame, together with reels, is coun- terbalanced by means of large wei.c'hts D, and can be readily raised or lowered by a hydraulic ram in the centi-^. When raised, the front ends of the reels are fi'ee to be tilled with yai'u ; when lowered, the hanks are immersed in the dye liquor. By means of the pulleys at c, the large cog-wheel b is made to revolve in alternate directions, and the motion is transmitted to the co^:- wheel of the reel immediately behind. This alternating motion is Chap. XII.] MACHINERY FOR COTTOX YARN. 253 necessary in order to keep the yam well opened out, and to prevent it from becoming entangled. When the cotton yarn is in the chain form, being intended for warps, a machine similar to that represented in Fig. 51 is employed. In its simplest form — namely, as a single-box machine — it consists of a rectangular wooden dyebeck a, fitted above and below with a series of wooden rollers, and at the end with a pair of squeezing rollers. The machine represented is a two-box machine, and is simply a duplication of that just described. Six or eight warp-chains G, separated by the guide-pegs at ! flB P iWfft"ft :0 Fig. 51. — Warp-Dyeing Macliiue. H, are passed side by side through the two boxes A and B in the direction indicated. The squeezing rollers c D prevent as much as possible the liquor in A from being drawn over by the warps into b, which contains a dif- ferent liquid. As the warps pass out of the machine, the squeezing rollers ef remove excess of liquid to facilitate the subsequent drying. At J the warps are again separated by guide pegs, and withdrawn from the machine by the reel K. The steam pipes L l serve for heating the solutions employed. Some machines (6.^., those used for dyeing logwood-blacks) have as many as six boxes, each box being filled with a different liquid, which may serve for mordanting, dyeing, washing, &c. The whole machine is specially arranged to make the several operations continuous. 254 DYEING OF TEXTILn FABRICS. [CLap. XIL Washing Machinery. — A very old form of ■vrashing machine is the so-called " "\rash-stocks," represented in Fig 52. It consists of a stout wooden or iron box A of special shape, in which are placed the bundles of yarn F to be washed. Two heavy wooden hammers b and c, suspended loosely at d, are alternately raised by the Fig. 52.— Wash-stocks. cams on the revolving shaft e, and fall on the yam in such a manner that its position is continually changed. A perforated pipe H supplies the trough with a copious supply of water. One of the best forms of modern hank-washing machines is that shown in Figs. 53 and 54, and made by Messrs. Duncan Stewart and Co., Glasgow. It consists of a U-shaped wooden trough e, with a series of radial, horizontal arms, c D, holding the yarn, supported immediately over it. The axes of the radial arms are fixed, at equal distances, to the endless chain a, 255 256 DYEING OF TEXTILE FABRICS. [Chap. Xn. which passes round the large pulleys b and c. The square reel of each ann revolves loosely on its central axis, the end of which rests on the outer edge of the trough. At the end nearest the chain each reel has a fixed wheel or pulley. The rails M y, on which these pulleys rest, receive a vigorous to-and-fro movement transmitted by the crank shaft l, and thus cause the reels to revolve rapidly to right and left alternately, and the haLks to vary their point of suspension. By the revolution of the large pulleys b and c, actuated by the endless screw o, the radial arms receive a rapid and con- tinuous progressive movement in the direction indicated by the arrows. At the points G and I the trough is dis- continued : fresh water enters at g, and the dirty water passes out at I. As the arms pass between the space g and F, the washed hanks are removed and at once replaced by others ready for washing. These enter the trough at i, and pass round, in a direction contraiy to that of the water-current, to the point g. The free, un- supported ends of the arms droop considerably between the points G and F, and they are again raised to the hori- zontal position by moving on to the sloping guide rail situated between p and i. The first movement is com- municated through the pulley at k. The handle H is for starting and stopping the machine. The machine is made of such a size that the hanks are sufficiently washed after having made one circulation of the trough, the whole operation being really continuous. Another excellent hank-washincr machine is that of A. Weser, Ell>erfeld, represented in Fig. bo. This machine consists of a cistern a, with water inlet at B, and outlet at c. Situated immediately above is a series of movable brass reels D, attached to a broad end- less belt or chain e. This is caused to revolve continu- ously in one direction rotmd the two large vertical pulleys F, by means of the driving pidley G, the endless band H, and the cog-wheels i. The hanks of yam are suspended on the reels at J, Chap. Xn.] MACHINERY FOR COTTON YARN. 257 and carried along by the lower reels so as to be partly immei'sed in the water of the cis- tern A. At K they are removed, being tho- roughly washed, and the empty reels above travel back to the end J. During their on- ward passage the hanks of yarn continuously receive vigorous and sudden backward and forward movements, since the whole system comprising the two large pulleys F, the endless belt e, and the reels d, resting on rockers l, or otherwise supported, is driven to- and-fro by means of the fly-wheel m and crank shaft N. Since, too, the inner discs of the reels rest on guide rails at o and p, each back- ward and forward movement of the belt and reels causes the latter to revolve rapidly on their axes alternately to ricjht and left. The total efiect of the simul- taneous, onward, re- volving, and to-and-fro movements described is 258 ii;.-a;.o.:>'^' Chap. XII.] MACHINERV FOR COTTON YARN. that the yarn is ra- pidly and effectually washed in a con- tinuous manner. Figure 56 gives a perspective view of this machine, slightly modified, in which tlie central system of reels, large pulleys, &c., is s-upported by means of the framework r, and moves to and fro on the wheels at s, instead of on rockers. In both machines the whole action imitates in a strik- ing manner the washing of a hank as it would be done by hand. Excess of water is best removed from wet yarn either Idj means of the hy- dro-extractor (see Fig. 72, p. 281), or by the hydraulic press represented in Fig. 90, p. 435. I>7-ying Machi- nery. — Cotton yarn is dried by suspend- ing the hanks on rods or poles, and 259 260 DYEING OP TEXTILE FABRICS. [Chdp. XII. hanging these in large and well-ventilated chambers or stoves heated Ly means of steam-pipes. Fig. 57 shows a continuous hank-drying arrangement of MM. Tulpin freres, Rouen. It consists of a closed wooden or iron chamber A B, provided with openings at each end for the entrance and exit of the yarn. The interior is heated by means of steam pipes, G, and contains ventilating fans H, for agitating the heated air. A ventilator situated above draws the moist air away, and causes fresh air to enter the chamber. An endless chain c traverses the interior of the chamber in a zigzag path, and supports the ends of the rods holding the hanks of yarn. The wet yarn is introduced at one end of the chamber e, and it is taken off dry at the other D. A small engine f supplies the power to move the endless chain. 218. Cotton Cloth. — Dyeing Macliinery. Cotton cloth or calico is dyed in a wooden or cast-iron dyebeck, over which a winch is supported (see Fig. 74). The beck is divided longitudinally by a perforated diaphragm, which is open below, in order to allow the pieces to pass freely beneath it. The pieces, stitched separately in the form of endless ropes or bands, are drawn by the winch continuously in the same direction, and are pre- vented from becoming entangled with each other by means of a series of wooden guide pegs which divide the several pieces. Fig. 58 gives a section of Mather and Piatt's spiral dyeing machine, largely used by calico-printers. A is the cast-iron dyebeck ; b the drain beneath ; c the winch ; D, a perforated steam-pipe passing through the beck ; e, the mid-feather or diaphragm ; F, the peg- rail for keeping the pieces from entangling ; G G, handles and tappet shafts for putting in motion or stopping the winch ; H is the steam- valve. About thirty to forty pieces stitched end to end are introduced at one end of the beck, and caused to pass Chap. Xn.] MACHIXERT FOR COTTON CLOTH. 261 over the winch and through the liquor in a spiral manner until the other end of the beck is reached. The first end of the cloth haA-incj been brought over the "winch to the front, is passed under a small pulley and led horizontally be- hind the strands of cloth, under a second pulley situated at the entering end of the beck, there to be stitched to the last end of the pieces and led over the winch again. By this arrangement a long continuous band of cloth is formed which gra- dually traverses the whole beck in spiral fashion, yet not in a state of tension, since a few yards of slack cloth are left in the loop of each spiral. This me- thod Ls adopted in order to obtain of dye. Quite a different dyeing machine, largely used by those vrho dye cotton linings, unions, &.C., is the so-called "jigger," a section of which is represented in Fig. 59. In this machine the pieces are dyed in the open Fig. 53. — Spiral Dyeing Machine. as much as possible a uniformity 262 DYEIXG OF TEXTILE FABRICS. [Chiip. xn. width. It consists of a wooden dvebeck, above which are two fixed rollers with oblique arms attached to theii' supports, so that a loose roller may revolve against them. The pieces to be dyed (say, five pieces of seventy-five yards each) are stitched end to end in the open width and beamed on a loose roller. This is placed on one of the oblique arms, and the piece is led down into the dye liquor beneath a wooden roller at the bottom, and then passed upward and around the fixed roller on the opposite side of the machine. When the whole length of cloth has run through the dye liquor, the movement is revereed, and the pieces are now caused to pass back through the dye ] liquor and on to the opposite fijxed roller. In this manner the pieces are passed to and fro several times, and only during the last passage, i.e., when they are properly dyed, are they again wrapped on one or other of the loose roUei^. In the most com- plete arrangement by L. Glover, the reversing of the modon takes place automatically. Washing }fachhiery. — There are numerous kinds of washing machines for calico. Perhaps the oldest form of machine still met with is the " dash wheel." It consists of a large, hollow, wooden drum, divided internally into four compartments, each of which is pro- vided with a hole for introducing the material Jets of water are admitted by slits, and there are numerous Fig. 59.— Lancashire Jigger Dyeing Machine. Cliap. XII.J MACHINERY FOR COTTON CLOTH. 263 holes in the periphery for the exit of dirty water. One or two pieces of cloth are put into each compartment of the drum, and during the revolution of the latter they are tossed from side to side. Figs. 60 and 61 represent a washing machine largely used by bleachers. It consists of a water trough, b, above which a pair of heavy wooden squeezing rollers a a, are supported. The pieces to be washed, stitched end to end in the chain form, are passed spirally between the 26i DYEING OF TEXTILE FABRICS. [Chap. Xn. squeezing rollers and down beneath a roUer R, fixed in the lower part of the washing trough ; c are guide-pegs to keep the several strands separated ; G is the water- main ; E the water-tap ; k and w are the screws, levers, and weights for regu- lating the f)res- sure of the squeezing bowls against other : each s s are strong brass rinses, or " straining eyes/' capable of being turned more or less ob- liquely, to give the proper degree of tension to the jDieces on entering the machine. The diagram represents tw^o sets of pieces being washed si- multaneously, en- tering the ma- chine at the ends and makhig their exit at the centre. Fig. 62 re- presents another washing machine in which the pieces also travel spirally between a pair of squeezing rollers. The water trough in tliis case is shallow and provided with two rollers — a square one A, immediately below the squeezing rollers, and a round one B, with ribs. The Fig. 61.— Side View of Fig. 60. Pig. 63.— Squeezing Eollerg. 266 DYEING OF TEXTILE FABRICS. [CLap. XIL square roller, or " beater," revolves in a direction con- ti-ary to tliat of tlie pieces, wMch tlius receive a violent flapping motion -vrhile moving in a state of tension along the suifece of the water. This machine serves admimbly for the expulsion of particles of dye woods, eneath the bowls. A more durable "squeezer" is that of W. Birch, represented in Figs. 64 and 65, and now very generally adopted in calico bleach works, kc. In this machine the cloth strand is confined and compressed in a narrow groove. The fabric E is di-awn into the squeezer with tolerably uniform tension ensur^ by reason of the swing Vjar D. The ten- sion bars T T are fixed in such a position that the cloth in going over the roller e and through the pot eye p, is somewhat tightly drawn to the lx)ttom of the grooved roller a before it passes through the " nip ; " this tension is necessary to prevent the piece from becoming damaged. Fig. 6i. — Birch's Squeezing Roller (Front riew). Chap. XII.] MACHINERY FOR COTTON CLOTH. 267 The cloth is drawn from the machine by means of a roller or winch actuated by the pulley M. The pressure of the brass disc b against the grooved roller a is regu- lated by the screw c connected with lever and spring ; N N are fast and loose dri^-ing pulleys. , . , . Drying MacJiinery.—Ca\ico is frequently dried m Fig. 65.— Side View of Fig. 64. stoves heated with hot flues or steam pipes situated in the basement (see p. 441). The internal arrangement for suspending the pieces varies. In some the building is one-storeyed, and the pieces are suspended in zigzag fashion from wooden rails placed near the roof, so that the loose folds come within a few feet of the iron grating over the flues. In 268 DYEING OF TEXTILE FABRICS. [Char- XII. others, the stove is divided into sevei-al storeys, each ^vith floors of iron grating, and furnished with wooden frame- work ha^'ing long parallel rows of upright wooden pegs. One selvedge of the pieces is passed alternately fi'om right to left, and twisted over the pegs. By this plan of Tig. C6. — Hot-air Drying Michiiie. hanging it is possible to pack a much larger quantity of cloth into a given space. Calico is also dried by means of the steam-cylinder drying machine described on p. 2SQ. When it is not desirable that the cloth should come into actual contact with a heated metallic surface — e.g., in drying cloth after impregnating it with mordants which are injuriously affected by a high temperature — the pieces may be made to traverse a closed hot-air chamber fitted with wooden rollers at the top and bottom. Fig. 66 shows the arrangement used by the calico-printer for drying the pieces immediately after printing. The fan d drives a cun-ent of air in a zigzag course along the channels c sur- rounding the steam pipes b. The heated air passes into the upper drying chamber, there moves in a direction Chap, xn.] Methods op wool dyeing. 269 contrary to that of the pieces, and makes exit at the top. In this particular case three different pieces of cloth are, dried simultaneously : the printed piece E, the back-cloth or grey G, and the endless blanket h. In some cases calico is dried on the so-called " tenter- ing " machine, similar to those used for woollen cloth {see p. 287). NOTES ON WOOL DYEING. 219. Methods of Wool Dyeing.— The methods of dyeing wool differ considerably from those emj^loyed for cotton and other vegetable fibres. Wool has a much greater affinity than cotton for most of those colouring matters in which the colour is ready formed and does not require developing by the use of mor- dants. Such is the case, for example, with a number of the coal-tar colours. It is sufficient in many cases to add the solution of the colouring matters to the cold or tepid water contained in the dye-bath, and after introducing the woollen material, to raise the temperature of the solution. With such colouring matters as require a mordant to develop the colour they yield, e.g., Logwood, Camwood, Cochineal, &c., the exact mode of dyeing varies according to the nature of the colouring principle and the mordant. The following three methods are employed in practice : — 1. The wool is first boiled in a solution of the metallic salt or mordant, and afterwards in a fresh bath con- taining the solution of the colouring matter or dyewood decoction. In other words, the wool is mordanted first and dyed afterwards. Dyers sometimes call the colours dyed by this method " prepared colours. " The mordanted cloth is said to be "prepared." 2. The wool is boiled in a solution of the colouring matter or dyewood decoction, and when, after some time, it has absorbed as much of the colouring principle as possible, the colour is developed and fixed on the wool by adding the mordant to the same bath. This method has been generally adopted with certain mordants wh:'ch 270 DYEING OF TEXTILE FABRICS. [Chap. Xlt produce dark or sombre shades of colour, and is called the " stuifing " and " saddening '' method ; the " stuffing " being the boiling of the wool -with the dye-stufi^ and the " saddening " the subsequent operation of developing the colour by adding the mordant 3. The wool is boiled in a solution containing both colouring matter and mordant from the beginning of the operation. In this case the colouiing matter and mordant combine with each other to form a coloured body which an excess of the mordant dissolves j fi-om the solution it is gradually absorbed by the wooL 4 Combination of 1 and 2. Mordant, dye, sadden. 220. The Mordanting and Dyeing Method. — The best example of the tirst method is afforded in the black dyeing of wool by means of potassium dichromate and Logwood. The method can be employed with most of the natxiral colouring matters or dye woods in conjunction with the following mordants — alum, potassium dichro- mate, chrome-alum, stannous chloride. ^Mien it is carried out in its entirety, the fabric should be well washed be- tween the mordanting and dyeing processes, in order to prevent any mordant which is not fixed on the wool from Ixring carried over into the dye-bath ; otherwise it would not only cause loss of colouiing matter by precipitating it in the bath, but might also prevent the dye-stuff fi'om yieldincr its colouiing matter to the solution. One advantage of this method is, that the solutions used for mordanting and dyeing can be preserved for suc- cessive lots of material, and need only to be replenished occasion^y. This implies that the mordant and colouiing matter are better utilised. Another advantage is that the dyer can " match-off " to any exact shade with very little trouble, since the mordant determines the tone of colour, and this being once fixed on the wool, the proportions of the various dyewoods required can be frequently altered until the de- sired shade is obtained. To ensure success in this matter it is only necessary to add in the Ijeginning a slight Chap. Xn.] METHODS OF WOOL DYEING. 271 deliciency of each dyewood, since it is evident that no modification of the proportions would rectify the eiTor caused by employing an excess of dyewood. As a rule, it may be said that from a given weight of dyewood and mordant, this method of dyeing produces colours which are deeper and richer in tone, and faster against milling than those obtained by any other method. ° Its only disadvantage is that it requires more time and labour, and, consequently, expense. 221. The Stuffing and Saddening Method. — The dyeing of a claret-brown by means of Camwood and feiTous sulphate IS a good example of this method which is appli- cable with some of the natural matters. TJie mordants generally employed are ferrous sulphate, copper sulphate, or potassium dichromate, and occasionally alum . ^ When Catechu is used as the dye-stuff, the saddenincr IS preferably effected in a separate bath— e.^., by means of potassium dichromate— since in this case both baths can be preserved and used continuously for successive lots of woollen material. The same may be said of dyeing the claret-brown just mentioned ; mdeed, the use of two baths in this method might be adopted, whatever be the colouring matter or mordant employed, but this would in many cases possess no material advantage over the method of mordanting first and dyeing afterwards. ° The following are the advantages when the stuffing and saddemng take place in one bath :— The time, labour, and expense are less. _ The desired tone of colour required may be some- times obtained more readily. The disadvantages are more numerous : The colour is generally not so fast against milling and rubbing, from which it appears that it is fixed more superficially than by the first method. • A^\K^'^^ ''^^^ ^^^^ ^^ "^y^ ^o an exact shade: indeed, this can be done only after long experience. The method demands that the coiTect proportions of dyewoods 272 DYEING OE TEXTILE FABRICS. [Chap. XIL required for any given shade be added to the bath before the saddening is effected, i.e., at a stage when the colour of the wool gives little or no indication of the ultimate colour produced by the action of the mordant. Any misjudged proportions wotild make little difference if, after saddening, one could add with effect fresh quantities of one or other of the dyewoods still needed. This, however, is inadmissible, if economy of dye-stuffs is studied, because the mordant present in the bath not only prevents the extraction of colouiing matter, but even tends to precipitate it within the dyewood itself, and in the liquor. It is e%ident, therefore, that it would only yield a useful effect after a large excess of dyewood had been added, and after this a further quantity of mordant would require to be added. As a rule, mis- takes in " shading '' of the kind mentioned are rectilied, so far as new shades are concerned, by adding to the dye-bath small quantities of some veiy soluble colouring matter requiring no mordant — e.c/., Cudbear, Turmeric, or Indigo Extract — by which it is comparatively easy to ob- tain the exact tint required, since they at once dye the wool with their proper and only colour. With such dyestuffs, however, these last touches of colour put upon the wool do not generally possess the fastness against light, soap, and milling, of the fundamental colour. The method gives rise in most cases to mtich loss of dyestuff, since the wool never absorbs the whole of the colouring matter, however prolonged the boiling with the dyewood before saddening may be, and all the colouring matter still unabsorbed is rendered insoluble and useless by the addition of the mordant or saddening agent. After saddening, the bath is thrown away, and the dense inky liquore and precipi- tates increase the pollution of the river or stream. There are, indeed, many cases in which saddening in a sepai^te bath does not quite ^ield such full colours as when a single bath is employed, since, even after the addition of the mordant or saddening agent, the dyeing still goes Chap. XII.l METHODS OF WOOL DYEINO. 273 on to some extent, the colour precipitated in the bath not being entirely insoluble, especially in the presence of a slight excess of the mordant. Such is the case, e.g., with Logwood and ferrous sulphate, Logwood and copper sul- jjhate. Madder and potassium dichromate, Logwood and alum, etc. 222. The Single Bath Method.— As an example of the third or " one-dip " method of dyeing, in which the wool is dyed from the beginning with a mixture of colouring matter and mordant, one may quote the dyeing of cochineal scarlet. This method can be carried out only with those colouring matters and mordants which, when used together, yield precipitates somewhat soluble in the acid liquid of the bath, e.g., Cochineal and stannous chloride, yellow dyewoods and alum or stannous chloride, LogAvood and ferrous sulphate or copper sulphate. Madder and potassium dichromate, tfec. Although in all cases the colour is not quite so full and deep as that obtained by mordanting first and dyeing afterwards, it may still be sufficiently near the maximum intensity obtainable, to cause the process to be preferred in practice before any other, since it means, of course, a great saving in time, labour, and steam. In some cases, too, it gives a very much brighter colour than the other methods ; the presence of the mor- dant in the bath prevents the impure extractive matters, tannic acid, eing added afterwards, in order that the temperatui-e may be suitably lowered previous to the introduction of the materials to Ije dyed. Another method is to add the colourins: matter to the dye-bath gradually, in which case the textile material should be withdrawn before each addition, unless the forai of dye-bath renders this unnecessary. A third plan, which proves to be efficacious, particu- larly when extremely soluble colourins: mattere are employed, is to add along with the colouring matter a certain proportion of some neutral salt, e.g.^ sodium sulphate, common salt, kc. This addition rendei-s the colouring matter somewhat less soluble, and hence it is absorbed by the wool more slowly. Above all, there Chap. XII. J MACHINERY FOR UNSPUN WOOL. 277 must be a continual motion given to the textile materials during the mordanting and dyeing processes, so that each portion may be equally presented to the action of the mordant or colouring matter. This is effected either by- hand or by machine. The operations which follow the dyeing process vary according to the material and the colouring matters employed. In general,' the loosely adhering dye-stuff" is washed off, the excess of water is removed, and the goods f^e Pig. 67. — McNaught's Wool-Drying Macliine {Section). are finally dried. Finishing processes are not considered in this manual. 225. Unspun Wool. — Dyeing Maddnery. The dye- vessel employed for loose-wool consists of a large open cylindrical cast-iron pan, similar to the indigo- vat shown on p. 305. It is provided with an emptying pipe below, covered with a sieve, beneath which enters also the steam-pipe for heating purposes. In many cases, direct fire heat is applied instead of steam, and for such large volumes of water as are usually employed in loose-wool dyeing the plan is economical. The stirring of the wool is effected by stout wooden poles, which are worked by hand. (Vacuum dyeing machines may also be employed.) Washing MacJdnery . — Loose- wool is usually washed in the dye- vat, by running off the dye-liquor, refilling the vat with water, and stirring up tlie wool with poles, re- peating the operation as frequently as may be necessary. 278 DYEING OF TEXTILE FABRICS. [Chap. XU. tii^mi HP m 5 The wool-scouring machine may also be iised for washing {see p. 100). Before drying, loose-wool is passed through a pair of squeez- ing rollers, or the excess of water is removed by the hydro-extractor. Drying Machinery. — The wool may be dried intermittently in an apparatus like that of McNaught, represented in Figs. 67 and 68. It consists of a series of steara- ])ipes c, immediately above which the wool is spread out on a large surface of galvanised wire netting h. Beneath, in a box-like space, two ventilating fans a drive the heated air through the layer of damp Avool. This may also be eftected by means of a centrifugal fan. Steam is supplied by the pipe e ; d is a tube for conveying oil to the bearings of the fans. Loose-wool may also be dried in a continuous manner by Nor- ton's machine, shown in Fig. 69. The damp wool is placed on the feeding-apron A, and passed continuously, in zigzag fashion, through a hot - air chamber, l)y means of the endless bands B. c, D, E. The dry wool leaves the chamber at i. The fan F drives the external air, heated by the steam-tubes H, into the space J, and thence into the chamber ; the moist air escapes by k ; M and L are the inlet and outlet tubes connected with the steam-pipes h. Chap. XU.J MACHINERY FOR WOOLLEN YARN. 279 226. Woollen Yarn. — Dijeiivj Machinery. For yarn dyeing, the simplest apparatus is a substantially made, Fig. 69.— ContmuoHS Wool-Drying Machine. rectangular, wooden box A, about f — 1 metre wide, and varying in length and depth to suit difierent quantities of material {see Fig. 70)^ also Fig. 45, p. 186. The water is heated by means of a perforated copper steam-pipe d, running centrally along the bottom. In l> -J-B- --P- Fi;-'. 70.— Woollen Y'am Dyeing Zl^Iacliine. the most complete arrangement, there is also a closed copper worm-pipe, so that the dyer may employ either 280 DYEING OF TEXTILE FABRICS. [Chap. Xn. tlie one or the other in order to maintain the liquid at a constant level. Cold water taps for tilling, and draw-off plugs, are conveniently situated. The hanks of yarn b are hung on square wooden Fig. 71.— Pitt's Woollen Yam Dyeing Machine. rods c, placed across the tank, and turned by hand, as described on p. 105 for yam-scouring. An excellent example of a machine specially adapted for dyeing icoolkn yarn is that of Messrs. Pitt Bros., and illustrated in Fig. 71. The vat, which is of the ordinary kind, is provided with a light ii'on frame a resting upon the edges of three of its sides and beneath the ends of the rods of yam. This frame can be moved up or down by means of the chains b, and thus the Chap.Xn.] MACHINERY FOR WOOLLEN YARN. 281 whole of the \vooden rollers holding the yarn can be im- mersed in or removed from the vat liquor simultaneously. When the frame is lowered, the ends of the axes of the rollers rest in the sockets c fixed on each side of the vat. The turning of the hanks is effected by loose wooden blades, which are inserted within the loop of the hanks, and close to the supporting roller. The ends of these blades project and rest in a series of forks or notches fixed on FiiT. 72. — Hvdro-extractor. horizontal rails d, situated on both sides of the vat. By means of a complicated system of levers e, actuated by a pail' of cams, the rails D are moved both vertically and horizontally in such a manner that a small circle is de- scribed by the vrooden blades which they suj^port. Each blade is raised above the roller on which the yarn is suspended, then moves away from it, and then falls ; the point of suspension of the yarn is thus being continually altered, and the varn is drawn intermittent! v across the rollers. The movement of the yarn is indeed very similar to that which it receives when worked by hand, the difference being simply one of degree and not of kind. Washing Machinery/. — Woollen yarn is washed by 9Q9 DYEING OF TEXTILE FABRICS. [Chap. XII. Fig. 73. — Arrangement for Drying Yarn in the oijen air. hand in a rectangular wooden box, identical with that used for dyeing, or the rods full of yarn are placed under a per- forated wooden drainer, where they receive a shower bath. Fig. 74— Pair of Winch Dyeing Machines for Cloth, 283 n 284 DYEING OF TEXTILE FABRICS. [Chap. XII. Excess of water is removed from woollen yam by- means of the hydro-extractor (Fig. 72). That made by T. Broadbent ossesses ceiiain advantages over the majority of blue colouring matters. It can be associated with other acid colouiing matters, and it dyes very level shades. Its only drawback is its extremelv fugitive character. 233. Indigo Grinding Mills. — One of the first necessities in employing Indigo in dyeing is to have it mtfimwfiiis. Fig. 81. — Indigo Grinding "M"ill- thoroughly well ground. 'When required for making In- digo Cannine it must be ground in the dry state, but for the indigo-vat it may be mixed with water, by which means the grinding is considerably facilitated. The oldest form of grinding machine is the stamping mill, provided with an aiTangement for jmssiug the ground Indigo through fine sieves. At present the mills generally employed consist of east-ii*on vessels, in which the Indigo is ground either bv the rolliDg of hea^^'v cannon balls, or of iron cylinders. The ball mills are said to give the finest powder ; the cylinder mills the greatest yield within a given period. Fig, 81 represents a section Chap. XIII.] INDIGO. 297 of one of the best forms of ball mills. It consists of a strong iron box enclosing several heavy cannon balls, which are pushed round by means of a pair of revolving arms. Sometimes the bottom of the box is flat, and heavy blocks of sand-stone are substituted for balls. 234. Application to Cotton. — The fermentatiim vats so much used in dyeing wool with Indigo, are never em- ployed for cotton, since it is essential that it should be dyed in the cold to obtain the best colour ; and, further, it permits the use of vats, in which the reduction of the indigo is effected in a manner more under control. Ac- cording to the reducing agents employed, the indigo-vats used for cotton may be named as follows : the ferrous sulphate vat, the zinc powder vat, the hi/drosulphite vat. 235. Ferrous Sulphate Vat. — This vat, usually known by the name of the lime and copperas vat, is the oldest, and perhaps the one still most commonly employed. The vats or dye-vessels are rectangular tanks of wood, stone, or cast-iron. The size varies according to the material to be dyed ; for calico they are generally two metres (6|- ft.) deep, two metres long, and about one metre broad, while for yarn-dyeing they are somewhat smaller. In order to economise the Indigo as much as possible, the vats are generally worked in sets of ten. The materials used in preparing this vat are : — Cloth. Tarn. AVater .... 4,000 litres or 750 litres. Indigo .... 40 kilos. „ 4 kilos. Ferrous sulphate , . 60—80 „ „ 6-8 ,, Slaked lime (dry) . . 50-100 „ „ 5-10 „ The chemical changes which take place during the '' setting " or preparation of the vat may be briefly summed up as follows. The lime decomposes the ferrous sulphate, and produces ferrous hydrate, which in the presence of the indigo rapidly decomposes the water, and becomes changed into ferric hydrate, while the liberated hydrogen at once combines with the indigotin to form 298 DYEING OF TEXTILE FABRICS. [Chajy. XIIL indigo-white. This last substance combines with the excess of lime present, and at once enters into solution. These reactions may be expressed by the following chemical formulae : — YeSOi + Ca(0H)2 = CaS04 + FeCOH^^. Ferrous stilpliate. Lime. Calcima sulphate. Ferrous hydrate. 2[Fe(OH)o] + 2H2O = Fe2'OH)5 -f R,. Ferrous hydrate. Ferric hydrate. Indigotin. ludigo-white. The order in which the ingredients are added is of comparatively little moment, and varies with different dyers. The most rational method, however, is to fill the vat ^sith water and add first the ground Indigo and milk of lime ; after raking up well, a solution of feiTOus sulphate IS added, and the whole mixture is systematically raked up at frequent intervals during twenty-four hours, until the Indigo is thoroughly reduced. With this plan, the actual reducing agent, ferrous hydrate, is always in the presence of an excess of Indigo, and the indigo-white the moment it is produced is dissolved in the excess of lime. Owing to the mixttire becoming rapidly thick and difficult to stir well, the more usual plan adopted is to put in the Indigo and feiTous sulphate first, and to add the milk of lime gradually. Lime is used in preference to caustic soda because the vat thus produced dyes the cotton more readilv ; and owincr to the film of calcium carbonate which forms on its surface, the indigo-white in the liquor beneath is less liable to become oxidised. The feiTOus sulphate employed should be as pure as possibla Any admixture of copper sulphate is injurious because of its oxidising infiuence, while the presence of aluminium sulphate and basic ferric sulphate, since these are quite inert as reducing agents, cau.ses loss of so much lime as is required for their decompo.sition, besides a useless increase of sediment. The use of a large excess of ferrous sulphate and lime should also be avoided Chap. XIII.l INDIGO. 299 for this last reason. Ferrous sulphate, containing copper sulphate and ferric sulphate, is readily purified by boiling its solution with iron turnings, whereby the copper is pre- cipitated, and the ferric sulphate is partly reduced to ferrous sulphate, or fully decomposed and precipitated. A freshly made-up vat is in good condition when numerous thick dark-blue veins appear on raking up the liquor, and the surface becomes rapidly covered with a substantial blue scum or " flurry." The liquid should be clear, and of a brownish-amber colour ; if greenish, it shows the presence of unreduced Indigo, and requires a further addition of ferrous sulphate. If the colour is very dark, more lime is required. At the end of every day's work the vats should be well raked up, and, according to their appearance, " fed " or replenished with small additions of lime and ferrous sulphate. The rake used for this purpose consists of a rectangular iron plate, with long wooden handle attached. Before dyeing, the flurry should be carefully removed with an iron scoop or "skimmer," otherwise it attaches itself to the cotton, and causes it to look uneven or spotted. Cotton yarn should be previously well boiled with water, in order to make it dye evenly. When dyeing light shades of blue, only a few hanks are dyed at once, the dipping, turning, and squeezing being performed with the utmost regularity. According to the depth of blue required, the duration of each immersion may vary from one to five minutes or more, and after wringing, the hanks are thrown aside, and allowed to oxidise completely. The amount of indigotin which is precipitated on the cotton is said to vary with the duration of the im- mersion ; if this be true it would appear that the cotton really attracts indigo-white from the vat solution, and is not dyed merely by reason of the indigotin precipitated from the portion of liquid absorbed by the fibre. The most economical method is to dye the cotton first in the 300 DYEING OF TEXTILE FABRICS. [Chap. XIII. weaker vats, and then to pass it through each succeeding stronger vat until the desired shade is obtained. For a dark shade, the cotton should not be put at once into a strong vat, because it would be difficult in this way to obtain even colours; and in the long run, the method would not be so economical. For light shades of blue, only a few of the weaker vats are needed. By this plan of always using the weakest vat first, so long as it yields any colour, each vat in turn becomes thoroughly exhausted. After dyeing, the carbonate of lime which is deposited on the fibre is removed by rinsing in sulphuric acid, 2° — 4° Tw. (Sp. Gr. 1 -01—1 -02). This operation removes the grey tint, and brightens the colour considerably. The cotton is finally dyed in a moderately strong vat^ wrung out and dried at 60° C. This imparts to it the coppery lustre so much admired. It is, however, entirely super- ficial, and may be removed by simply washing in water. As a rule, however, washing is avoided, since the indigo is apt to rub ofi", and the colour may look bare and wanting in body and intensity. Yat blues are improved in colour by passing the goods through lime-water or a hot soap bath, probably because of the removal thereby of some yellow colouring matters. When dyeing cotton cloth or calicoes, the dry pieces are fastened by the selvedges on a rectangular wooden frame, having small brass hooks at the top and bottom ; they are stretched moderately tight, and each fold is per- fectly free. When filled the frame is alternately dipped beneath the surface of the vat liquor for fifteen to twenty minutes, and then raised above the vat by means of ropes and pulleys, in order to expose the calico to the air, so that indigotin may be regenerated and precipitated on the fibre. During the immersion it is customary to stir the liquor gently by means of a "muddler," i.e., a short- handled rake having a wooden head. Another method of dyeing calico, sometimes called " skying," because used for light blues, is shown in Fig. 82. Chap. Xlli.] INDIGO. 301 The pieces are passed through a series of rollers, arranged on a wooden frame immersed in the vat A. At the point of exit they pass through a pair of squeezing rollers, and are then led over a similar system of rollers b, outside the vat, for the purpose of oxidation. The whole process ^fmjtigt'i*ii!,-/.[ Fig. 82. — Continuous Indigo Dyeing Machine. may be repeated two or three times, according to the in- tensity of colour required. After leaving the vat, the pieces are first rinsed in cold water, to remove the loose lime and Indigo adhering super- ficially, and then in dilute sulphuric acid, 4° — 8° Tw, (Sp. Gr. 1*02 — 1"04:), to dissolve off the calcium carbonate; they are finally washed and dried. All the indigo washed-off in the rinsing pits, as well as the sediment of the vats themselves, must be collected in special tanks, in order to recover the indigo. According to F. C. Calvert, the vat sediments consist 302 DYEIXG OF TEXTILE FABRICS. [Chap- Xnf. largely of an insoluble compound of indigotin and ferrous oxide, forming a bulky flocculent green precipitate. From this the indigotin can be recovered by decomposing it in the cold with strong hydrochloric acid. Another method is to mix the vat sediments vrith. water, and boil -with some cheap, energetic reducing agent, e.^., with caustic soda and orpiment. After settling, the clear liquid is drawn oflf, and oxidised by pumping it into a trough which stands at a high level, and allowing it to flow into a large tank ; here the pre- cipitated indigotin is washed and collected. By adopting such methods of recovery, the total loss of Indigo may be ^'educed to 2 — 3 per cent, of the original weight employed It is sometimes the custom to dye the cotton or " bottom " it with catechu bro^^^l, manganese bronze or brown, or a blue shade of aniline black, previous to introducing it into the indigo vat. By this means, very deep blue shades can be obtiiined with less indigo than would otherwise be required. It is well to remember that when aniline black is used the colour may be liable to become green on exposure. In order to add a fictitious purple bloom or rich effect to the colour, vat blues are sometimes dyed afterwards or " topped " in a dilute solution of Methyl Violet or Methylene Blue, and dried without washing; less fre- quently, they are dyed a logwood blue. 236. Zinc Powder Vat. — This vat is frequently used on the Continent, and also in Great Britain. It is founded on the fact that zinc in the presence of lime and Indigo readily decomposes water, and combines with its oxygen, whilst the liberated hydrogen reduces the indigotin to indigo-white, which is at once dissolved by the excess of lime present Zn 4- HoO = ZnO -f- H.. The relative proportions used of the several ingredients vary according to their quality, especially as regards the Indigo employed. Chap. XIII.] IXDIGO. 303 The following may be considered as average amounts : Water 4,000 Htres Indigo 40 kilos. Zinc powder 20 Slaked lime 20 The whole is well stirred occasionally during eighteen to twenty-four hours, when it is ready for use. Lime and zinc powder are added as occasion requires. It is an extremely simple vat, easy to work, and possesses even certain advantages over the " lime and copperas " vat. In the first place, the sediment is reduced to about one- seventh of that in the vat referred to. Then the absence of ferrous sulphate removes the possibility of the forma- tion of the insoluble compound of indigotin with ferrous oxide referred to on the previous page. Hence this vat can be used for a much longer time without emptying, than the "lime and copperas" vat, and there is little or no loss of Indigo. Its chief defect is that it is liable to be muddy and frothy, from a continuous slight disengagement of hydro- gen gas. No hydrogen is given off, however, until the whole of the indigo is reduced, so that much froth denotes the presence of excess of zinc. If there be only little froth, it is removed by vigorously stirring up the vat several times, and then allowing it to settle, but with a large excess, a further addition of Indigo should be made before stirring. After settling for an hour, the vat should be sufficiently clear for dyeing. If the vat is muddy, the same remedy must be applied, since the cause is the same. It is of no use to let it stand for a long time in the hope that it will settle; the hydrogen simply accumulates, and the liquid becomes more muddy still. The liquid must be vigorously stirred up, in order to liberate the hydrogen from the sediment. The dyeing should be completed before the liquid has had time to become muddy again. Experience alone can teach the exact amount of zinc powder which should be 304 DYEING OF TEXTILE FABRICS. [Cliap. XIH. used, SO that the vat may be maintained in an effective condition, yet free from the defects mentioned. Some- dyers find it an advantage to add about 12 — 20 kilos, of iron borings. These act mechanically, by present- ing a large and rough surface, from which the hydrogen gas is more easily liberated, and thus a clear vat is more readily obtained. 237. Hydrosulphite Vat. — This vat is prepared for cotton exactly in the same way as for wool (see p. 308). The cotton, however, should be dyed in a cold solution. 238. Application to Wool. — In order to utilise- the Indigo to the fullest extent, it is previously ground with the addition of water, and added to the dye-vessel in the form of a fine smooth paste. The " vat " or dye-vessel in which the reduction of the indigo and the dyeing takes place, is a large tank, generally made of cast-iron (about 2 metres wide and 2 metres deep). For dyeing unspun wool it is generally round, for piece-dyeing, square. The whole is enclosed in brickwork, so arranged that the upper portion of the vat is surrounded by a chamber or canal, into which steam can be admitted. By this means the liquid of the vat is heated from the outside, and a regular temperature can always be maintained, without any danger of disturbing the sediment. During the "setting" of the vat the contents are stirred up, either by hand, by means of a rake, or by a mechanical arrangement fixed in the bottom of the vat, and driven by machinery. Before dyeing, the contents are allowed to settle, since the textile material must always be dyed in the clear liquid. The disturbing of the sediment is prevented as much as possible by sus- pending in the vat, 1 metre below the surface, a so- called " trammel," i.e., an iron ring or frame, across which coarse rope network is stretched. The accompanying figure (Fig. 83) gives the section of a well-arranged round indigo-vat for wool dyeing, with mechanical stirrer, &c. A is the steam-chamber surround- ing the vat, B the steam-pipe for heating it, J the Chap. XIII.] INDIGO. 305 trammel -net, I the emptying- pipe ; D is a fixed bar sup- porting the stirring-screw c and the cone E. The parts drawn in dotted lines represent the movable portions of the stirring arrangement ; G is a strong wooden bar which can be readily fixed across the top of the vat ; it supports a pair of cogwheels, and the fast and loose pulleys H ; p is a vertical connecting shaft, which by reason of the Fig. 83.— Woad Vat. guiding cone E can be readily connected with the screw c. A cheaper but less substantial arrangement is that in which the vat is made of wood, and heated internally by a copper steam-pipe forming a spiral half-way up the walls of the vat. When not in use for dyeing, and to prevent loss of heat and oxidation of the reduced indigo, the vat is covered with a wooden lid, which is divided into two or three pieces, for the sake of convenient handling. It is often the custom to throw over it a woollen cloth cover in addition. According to the materials used in u 306 DYEING OF TEXTILE FABRICS. [Chrp.XIIl. preparing or " setting " ^ vat for woollen dyeing, the fol- lowing kinds may be distinguislied : the wood vat, potash vat, soda vat, urine vat, and hydrosulphite vai, 239. Woad Vat. — In setting this vat, the following substances are employed for a vessel of the dimensions already given : Indigo, 15 kilos. ; woad, 300 kilos. ; bran, 10 kilos. ; Madder, 2 — 15 kilos, ; dry slaked lime, 12 kilos. The vat is first partly filled with water, the crushed woad is then added, and the whole is well stirred up and heated to about 50° — 60° C. This temperature is main- tained for twentv-four to thirtv hours, the stirring beino: repeated at intervals during the first two hours. The well-gi'ound Indigo, also the bran, Madder, and about half the total quantity of lime, are now added ; after well raking up the whole mixture, the vat is covered over, and left to itself for twelve to twenty-four hours. By this time fermentation has generally well begum It is recognised by the following appearances : the surface of the vat4iquor becomes covered with a coppery- blue scum or "flurry." On gently stirring the liquor, it is seen to possess a greenish-yellow colour, interspersed with blue veins or streaks of regenerated indigo, and the general odour of the vat is agreeable. If the bottom of the vat liquor is disturbed, a slight froth appears on the surface, and on bringing up a portion of the sediment with the rake, it shows evidences of being in a state of slight fermentation, and smells somewhat sour. A piece of wool immersed in the liquid for a short time, and then exposed to the air, becomes dyed blue. All these appearances denote that the fermentation is progressing satisfactorily, and it now only becomes necessary to keep it steady and under control, by main- taining the temperature at 45° — 50° C, adding, every two or three hours, a portion (one-eighth to one-fourth) of the remaining quantity of lime, and vigorously stirring the whole contents of the vat after each addition. In the course of the next twelve to twenty-four hours, provided the fermentation continues to progress favourably, the Chap. Xni.] INDIGO. 307 vat is ready to be used for dyeing. Excessive fermentation is prevented by well-timed and suitable additions of lime ; sluggish fermentation, on the contrary, is accelerated by making further additions of bran. The dyeing power of the vat is maintained by adding, after each day's work, fresh quantities of lime and bran, and every other day 5 — 8 kilos. Indigo ; care being taken to kee]) the tem- perature of the liquor at about 50° C. After three or four months, or whenever the vat sediment becomes so bulky that there is a difficulty in obtaining the clear-liquor space necessary for good dyeing, no further additions of Indigo are made ; the vat is then used for dyeing light blues, and when its colouring power is exhausted, the whole contents are thrown away. The woad vat gives rich and brilliant colours, and serves equally well for light and dark shades of blue. It is the vat most largely employed in Yorkshire for woollen dyeing. 240. Potash Vat. — This vat is made up with the following ingredients: Indigo, 10 kilos. ; Madder, 2 — 5 kilos. ; bran, 2 — 5 kilos.; carbonate of potash, 10 — 15 kilos. The bran and Madder are first heated to 80° — 100° C. for 3 — 4 hours with water, after which the potash is added and dissolved, and the liquor is allowed to cool down to about 40° C. The ground Indigo is then added, the whole is well stirred, and left for a period of 48 hours to ferment, only an occasional stirring every 12 hours or so being needed. The appearances of a healthy state of fermentation in the potash vat are similar to those observed in the woad vat. This vat, owing to the absence of such a highly nitro- genous substance as woad, is less liable than the woad vat to get out of order, and is altogether more easily managed. It also dyes more rapidly than the woad vat, gives deeper but duller shades of blue, and the colour does not come ofi' so much on milling with soap and weak alkalis. It is best adapted for very dark shades of navy blue. If unspun wool is dyed in *Jiis vat, care must be taken to 308 DYEING OF TEXTILE FABRICS. [Chap. XKL xN'ash it thoroughly in water afterwards, otherwise it is apt to spin badly. 241. Soda Vat (G-ennan Vat). — This vat is set with the following materials : 10 kilos, of Indigo, 60 — 100 kilos, of bran (or 10 — 15 kilos, of treacle, instead), 20 kilos. of carbonate of soda crystals, 5 kilos, of slaked lime. The bran is first boiled with the water for 2 — 3 hours, the liquid is then cooled down to 40" — 50° C, the remaining ingi-edients are added, and the whole is well stirred up and left to ferment for 2 — 3 days, with only an occasional stirring. During the progress of the fermentation, lime and soda, as occasion requires, are added from time to time. After being used for dyeing, the vat is replenished with Indigo, soda, and lima This vat is cheaper than the potash vat, because of the diSerence in price between potash and soda ; it also lasts longer. It is, however, more liable to get out of order, though always more easily managed than the woad vat. 242. Urine Vat. — This vat, although of minor impor- tance, is suitable for working on a small scale. It is used by those who only require to dye vat -indigo blues occasionally, or in comparatively small quantities. The vat is made up as follows : — Add to 500 litres of stale urine, 3 — 4 kilos, of common salt, and heat the mixture to 50° — 60° C. for 4 — 5 hours, with frequent stirring ; then add 1 kilo, of ]SIadder and 1 kilo, of ground Indigo, stir well, and allow to ferment till the Indigo is reduced. In this vat the indisfo-white dissolves in the ammonium carbonate arising fi'om the decomposition of the uiea contained in the urine. 243. Hydrosulphite Vat. — The active reducing agent in this vat is a solution of hyf)Osulphurous (hydro- sulphurous) acid, which may be produced by the action of zinc upon a solution of sulphurous acid, according to the following equation : IL,S03 -f Zn = H,SO. + ZnO. Sulphurous Ziuc. Hypos iilphur- Zinc oxide, acid. ous acid. Chap. XIII. I INDIGO. 309 In practice the zinc is allowed to act upon a concen- trated solution of sodium hydrogen sulphite (bisulphite), instead of sulphurous acid, in which case the reaction is somewhat more complicated, there being produced a solu- tion of sodium hydrogen hyposulphite and zinc sodium sulphite which separates out, thus : Zn + SXaHSOs = NaHSOa ^ ZiLN'a2(S03)2 + HgO. Sodium hydro- Sodium hydro- Zinc Sodium sul- gen sulphite. gen hyposul- phite. phite. Tlie reduction of the indigotin by means of the acid sodium hyposulphite may be represented by the follow- ing equation : C16H10N2O2 4- NaHSOg -t- NaHO = CigHjaNaOa -f NaaSOg. Indigotui. Acid sodium Indigo-white. Disodium hyposulphite. sulphite. ■ It is not customary to reduce the indigo in each vat separately, but rather to make a very concentrated solution of reduced indigo, and to use this stock solution for preparing and replenishing the dye- vats. The setting of a hydrosulphite vat naturally divides itself into three phases. 1st, The formation of acid hyposulphite of soda ac- cording to the above equation. 2nd, The changing of this acid hyposulphite into neutral hyposulphite by mixing it with lime. 3rd, The mixing of this solution with Indigo and a further quantity of lime, in order to produce the stock solution of reduced indigo. Fig. 84 shows a suitable apparatus in which to conduct the first two operations. (1) A vessel a provided with an agitator, and which can be hermetically closed, is packed full of small rolls of zinc-foil, then filled up with bisulphite of soda, 55° Tw. (Sp. Gr. 1*275), and thoroughly saturated with sulphurous acid. The size of the vessel should be just adapted to the quantity of hyposulphite required for immediate use, and so that it may be entirely full of zinc, in order to 310 DYEING OF TEXTILE FABRICS. fChap. Xm. prevent oxidation as much as possible. The zinc and bisulphite of soda are allowed to act upon each other, with occasional stirring, for about an hour at least. The sodium hydrogen hvposulphite thus produced stands at 62° Tw. (Sp. Gr. 1-31), and, since it is very unstable, it must be used at once, either for reducing indigo or for making the neutral sodium hyposulphite. One litre bisulphite of soda, 55° Tw. (Sp. Gr. 1-275) requires 100 — 125 grams of zinc, of which quantity about 50 grams dissolve during the opei*ation. Granulated zinc or zinc powder may be used instead of zinc-foil, but the former retains much of the liquid when the vessel is emptied; and cannot be so readily washed. The latter is perhaps the best form of zinc to use, but it varies con- siderably in composition, and owing to its beincr in the state of such a fine powder, the liquid heats considerably during the mixing, so that there is alwavs the danger of a portion of the hyposulphite being decomposed. When- ever the acid hyposulphite of soda has been drawn ofi^ the zinc should be rinsed with water, and, if not im- mediately required again, the vessel should be filled up with water, in order to prevent, as much as possible, the oxidation of the zinc. "When a fresh quantity of hvposul}5hite is to be made this water is di^awn off and the zinc is rinsed, first, with water slightly acidulated with hydrochloric acid, and afterwards with water. The small quantity of zinc Fig. 84. — Apparatus for Preparing Hjdrosulpliite Vat Liquor. Chap. XTIL] INDIGO. 311 dissolved in the previous operation is replaced by an addition of fresh zinc-foil, so that the vessel may be entirely full. Bisulphite of soda solution is then poured over it, and the process as already described is repeated. (2) In order to change the unstable acid sodium hypo- sulphite thus produced into the more stable neutral hyposulphite, it is drawn oflf into another closed vessel b, and there mixed with milk of lime, which precipitates zinc oxide and calcium sulphite. One litre of acid sodium hyposulphite, 62° Tw. (Sp. Gr. 1 'SI) requires about 460 grams of milk of lime, containing 200 grams of quicklime per litre. The mixture is well agitated, and after settling the clear liquid is drawn off. A better yield is obtained by ])assing the mixture through a filter-press. The weight of neutral hyposulpliite thus obtained is about the same as that of the original sodium bisulphite, and it has a density of about 36° Tw. (Sp. Gr. 1-12). It is best to em- ploy the solution as soon as possible for reducing Indigo, and not to make more than is required for immediate use. If it is ever found necessary to keep it for some time, it must be made alkaline by adding a little lime. (3) The stock solution of reduced indigo is made by heating to a temperature of 70° — 75° G the following mixture : 1 kilo, of Indigo, 1 — 1'3 kilos, of milk of lime (containing 200 grams, of quicklime per litre of water), and so much neutral hyposulphite, 36° Tw. (Sp. Gr. 1"18), as is obtained from 8 — 10 kilos, of concentrated sodium bisulphite. The indigo is rapidly and completely reduced, and a comparatively clear greenish-yellow solu- tion is obtained, containing about one kilo, of Indigo per 10 — 15 litres of solution. With an insufficiency of lime, part of the indigo-w^hite is not dissolved, but remains as a dense wdiite precipitate. In setting a hydrosulphite vat, the vat is first filled with w^ater heated to 50° G.; it is then deprived of the oxygen it naturally contains, by adding a little of the neutral hyposulphite. The concentrated stock solution of reduced indigo is then added in sufficient quantity to make a vat of the required strength, 312 DTEIKG OF TEXTILE FABRICS. fChap. XIII. and since there is no sediment, the dyeing may be at once proceeded with- The dyeing power is maintained by adding fresh quantities of the c^oncentrated solution of reduced indigo. The liquid of the vat should always contain an excess of hyposulphite. It shoidd have a yellow colour, and be clear. If from anv cause excessive oxidation of the indigfo- white takes place, and the liquor becomes greenish, a little more hyposulphite, and possibly also milk of lime, must be added, and the whole heated to 70° — 75° C, in order to accelerate the reduction of the indigo and restore the normal yellow colour. When the vat is in use the alka- linity of the liquid increases, and there is a danger of both the colour and the fibre l^eing injured ; hence it is advisable to partially neutralise the excess of alkali from time to time, by making slight additions of dilute bydrocliloric acid 244. Defects in Indigo Vats. — All the fermentation vats are subject to derangements, by which they become more or less useless. The most serious defect is produced by using a deficiency of lime, in which case the fer- mentation becomes more and more active ; if allowed to proceed too far, the indigo is totally and irretrievably destroyed- This defect is recognised by the following character- istics : The flurry disappears, the vat liquor has a muddy appearance, and gives off a very disagreeable odour ; it has a dirty reddish-yellow tint, and acquires the property of gradually destroying the colour of a small piece of indigo-blue cloth, which may be plunged into it. The only remedy to be applied, in such a case, is to heat the vat liquor to 90° C, and add lime or potash, P ^^^^act; Indigo Carmine [a.H.N.O^ (afeUg),]. I his colouring matter is the product of the action of strong sulphuric acid on Indigo. 248. Application to Co«o7z.— Indigo Extract has no aanity for cotton, and cannot be used by the cotton dyer It is^^owever, occasionally used by bleachers for tintincr' ^49. Application to iroo/.— The blue obtained on wool, by means of Indigo Extract and Indigo Carmine is sometimes called " Saxony blue." It is a much brio-hter colour than that obtained by means of the indio-o-vat but IS very far from being so fast either to li^ht or to the action of soap and weak alkalis. Hence it does not stand milling well. Wool must always be dyed with the above-mentioned colouring matters in an acid bath. When "sour extract" {i.e., indigotin-disul- phonic acid, containing free sulphuric acid) is used, no otner addition to the dye-bath than the Extract itself is necessary. The wool may be entered at 40'— 50° • the temperature of the bath should then be gradually raised in the course of half an hour to the boiliua point the dyemg continued for half an hour lono-er Bv dyeing at 70-80° C, a purer blue is obtained? but the colour IS apt to have an uneven, speckled appearance. Boiling levels the colour, but makes the shade greener When Indigo Carmine is employed, this being the sodium 318 DYEING OF TEXTILE FABRICS. [Chap. XIII salt of indigotin-disulphomc acid, it is necessary to add to the dje-bath, along with the colouring matter, 5 — 10 per c-ent. of sulphuric acid, 168° Tw., so that this may com- hine with the sodium, and liberate the colour-acid itself. Without this addition the full colouring power of the Indigo Carmine would not be developed. The addition of 10 — 20 per cent, of sodium sulphate to the dye-bath along with s\ilphuric acid tends to make the colour uni- form or level. Sometimes alum is also added to the bath in order to mordant the wool slightly, and permit the application of Logwood and other polygenetic colouring matters. 250. Application to Silk. — Dye at a temperature of 40° — 50° C, in a bath acidified with svdphuric acid, and containing the amount of Indigo Carmine solution neces- sary to produce the depth of shade required. Another method is, to mordant the silk first with alum by steeping twelve hours in a solution of 25 per cent, of alum, and then, without washing, to dye in a solution of Indigo Carmine with the addition of about 10 per cent, of alum to the dj-e-bath. If scroop is required, a further addition of a little acetic acid or cream of tartar is necessary. In this case the ahim acts in no sense as a mordant for the lodigo Carmine, but makes it possible to redden the shade, or even to produce a violet colour, by adding Cochineal decoction to the dye-bath ; by the further addition of decoctions of Old Fustic, Logwood, Orchil, (tc, various shades — grey, drab, brown, &.c. — may be obtained, according to the amount of each colouring matter em- ployed. By adding to the dye-bath a decoction of 10 — 20 per cent, of Logwood, a dark shade of blue is obtained ; the addition of too much Logwood decoction, however, must be avoided, otherwise the colour is apt to become duU. The most rational method of adding the colour yielded by Logwood to that of the Indigo Carmine, is to dye with the two colouring matters in separate baths. Chap. XIII.] DYEIXG WITH LOGWOOD. 319 LOGWOOD. 251. This dyewood consists of the heart wood of Hcematoxylon camj^echianum, growing in Central America. 252. Application to Cotton. — The principal use of Logwood in cotton-dyeing is for the production of blacks and greys ; it may, however, also serve for purples, blues, and numerous composite colours. In conjunction with other colouring matters, it is employed for the production of numerous compound shades, its use being, in such cases, to make the colour darker, or of a bluer tone. 253. Logwood Blacks. — The method of obtaining a logwood black consists essentially in mordanting the cotton with a salt of iron, and then dyeing with a decoc- tion of Logwood. Numerous modes of applying this simple process are in general use, but the principle i? always the same. In order to mordant the cotton, it may be worked in a cold solution of pyrolignite or nitrate of ii'on, at about 5° Tw. (Sp. Gr. 1-625) till • thoroughly saturated; after squeezing, the iron is fixed by working in a cold weak bath of sodium carbonate, or milk of lime ; the cotton is finally w^ell washed in water. Anotlier method of mordanting, and one wdiich gives faster blacks, is to fix on the fibre a tannate of iron instead of ferric oxide, as in the last case. Work the cotton in a cold infusion of about 30 — 40 per cent, of Sumach, or its equivalent of other tannin matter (ground Gall-nuts, Myrabolams, &c.), and allow it to steep for several hours, or even over-night; remove the excess, and, without washing, work for about half an hour, in a cold solution of pyrolignite or nitrate of iron at 2° — 4° Tw. (Sp. Gr. rOl — 1'02), and wash well. In order to remove all traces of acid, and to fix more completely on the fibre a basic salt of iron, it is advisable before washing to work the cotton in a cold bath of chalk- water, or in weak milk-of-lime. Not unfrequently a lime bath is applied immediately after sumachiiig and before passing into the 320 DYEING OF TEXTILE FABRICS. [Chap. XIIL iron bath. In this case a tannate of lime will be formed upon the libre, and the double decomposition with the iron salt is facilitated, since the lime at once takes up the acid liberated. In wai-p dyeing the whole process is continuous, and the cotton, after being steeped in a decoction of mvrabo- lams is passed successively through baths containing lime-water, nitrate of iron, logwood liquor, dilute iron solution, and water. For low-class goods, many dyers substitute fen-ous sulphate for the pyrolignite and nitrate of iron. The pyrolignite of iron may also be mixed with an equal or somewhat smaller amount of aluminium acetate (red liquor) at 5'- Tw. (Sp. Gr. 1-025), in which case it may be better to fix the mordants by working the cotton for a quarter of an hour at 50^ — 60" C, in a dilute solution of phosphate or arsenate of soda. An aluminium mordant alone would give a dull lilac shade, but along with an iron mordant it helps to re- move the unpleasant reddish or rusty appearance of the blacks otherwise obtained. When Catechu is the tannin matter employed, the cotton should be worked in a boiling decoction of it, and allowed to steep till cold, in order to effect the precipita- tion on the fibre of the maximum amount of catechin. The cotton may afterwards be worked b — 15 minutes in a boiling solution of bichromate of potash (five grams per litre ', before passing it into the bath of pyrolignite of iron, though this is not absolutely necessaiy. By whichever method the mordanting is effected, the dyeing takes place in a separate bath containing a suitable amount of freshly -made Logwood decoction, to- gether with a small quantity of extract of Old Fustic, or of Quercitron Bark. If an iron mordant only has been employed, it is beneficial to add also a small quantity of cop|>er sulfthate to the dye-bath, in order to prevent the cotton from acquiring the rusty appeai-ance already referred to. Chap. Xin.] LOGWOOD. 321 The cotton is introduced into the cold dye liquor, and the temperature is gradually raised to the boiling point. After dyeing, the cotton may be passed through a solution of bichromate of potash, 0.5 gi-ams per litre, at 60' C. This operation gives intensity and fastness to the black, since any excess of colouring matter is fixed as a chromic oxide lake. The dyed cotton is washed and worked in a solution of soap, five grams per litre, at a moderate temperature, then squeezed and dried. This final soaping removes any bronze appearance, and imparts to the colour a bluer and more agreeable tone. The cot;:on also acquires a softer feel. The following is a method by which a chrome black on cotton can be obtained in a single bath : Dissolve 1 -5 kilos, of bichromate of potash in a small quantity of water, mix the solution Avith 500 litres of Lo<'- wood decoction at 3^ Tw. (Sp. Gr. 1-015), and add 3^5 kilos, of hydrochloric acid, 3i^ Tw. (Sp. Gr. M7). The cotton is introduced into the cold solution, and the tempe- rature is very gradually raised to the boiling point. The cotton acquires at first a deep indigo-blue shade, which changes to a blue-black on washing with a calcareous water. A slight modification of this process which may be adopted, is to work the cotton in a solution containing at^ first only the bichromate of potash and hydrochloric acid, and to add the decoction of Logwood to the bath, in small portions from time to time, gradually raising the temperature as before. Another method of producing a Logwood black, is to dye in a bath containing Logwood extract, and copper acetate, entering the cotton cold, raising the tempera- ture gradually to 50" C, and dyeing at that temperature until the colour is sufficiently developed. Copper sulphate, to the amount of about 4 per cent, of the weight of cotton, is frequently used instead of acetate, and an addition of 4 per cent, of soda-ash is made V 322 UYEING OF TEXTILE FABRICS. [Chap. Xin. to the bath along with 20 per cent, of solid Logwood, extract. The cotton is passed rapidly through this mixture, heated to 60° — 80° C, and then allowed to oxidise or " smothoj* " for 5 — 6 hours. This process requires to be repeated several times before a full black is obtained. The method is not economical for ordinary use, but it is said to yield a black which withstands milling with soap very well. Carbonate of copper may also be applied in the above process, instead of copper sulphate and soda-ash. The methods already given may be adapted to the dyeing of unspun cotton. The following method of dyeing a chrome black is said to be specially applicable to such as must withstand the operation of fulling. Wet out the cotton well in boiling water, then boil in a strong solution of about 30 per cent, of solid Logwood-extract, drain, and allow it to lie exposed to the air for some time ; complete the oxidation thus begun, by working it one hour in a cold solution of 8 per cent, of bichromate of potash and 6 per cent, of copper sulphate, wash and complete the dyeing in a bath containing 10 per cent, of Logwood extract ; enter the cotton cold, and raise the temperature gradually to the boiling point. Wash, soap, and dry. In the first bath the cotton simply absorbs the colouring matter of the Logwood ; in the second this is oxidised, and at the same time combined with a sufficient amount of mordant, copper and chromic oxide, to enable it to take up still more colouring matter in the third bath. The first Logwood bath is analogous to the taimin bath alluded to in a previous process (p. 319). 254. Logwood Greys are obtained by working the cotton for a short time at 40° — 50° 0. in a weak decoction of Logwood (1 — 5 per cent.), then in a separate bath con- taining a weak solution of ferrous sulphate or potassium dichromate, and washing. Many dyers adopt the ap- parently iiTational method of mixing the ferrous sulphate and Logwood solutions^ and dye at once in the inky liquid thus obtained. Comparatively little precipitate, Chap. XIII.] LOGWOOD. 323 however, is produced in the dye-b^th in this case, and the colour is for the most part developed on the cloth itself during the subsequent oxidation by exposure and wash- ing. The shade of gi'ey may be modified ad libitum, by adding to the Logwood bath a small proportion of decoc- tions or extracts of tannin matter. Old Fustic, Peach- wood, &c. 255. Logwood Purples are obtained by mordanting the cotton in a weak solution of stannous chloride, then washing and dyeing in a separate Logwood bath. The colour is tolerably fast to soap, but not to light. 256. Logwood Blues on cotton are now seldom dyed, because of their fugitive character. To obtain them, work the cotton in a bath containing a decoction of Log- wood and a small proportion of copper acetate or sulphate, raising the temperature gradually to 50^ C. The tone of colour has great similarity with that of an indigo- vat blue. 257. Ajjplication to Wool. — Logwood is the essential basis of all good blacks on wool, although other colouiing mattei^ are frequently used along with it, either to modify the particular shade of black, or to add to its intensity and permanence. According to the materials employed, we may distin- guish the following kinds, Chrome black, copperas black, and woaded black. 258. Chrome Blacks are produced by fii-st mordanting the wool for 1 — 1^ houi' at 100° C, with 3 per cent, of bichi'omate of potash and 1 per cent, of sulphuric acid, 168" Tw. (Sp. Gr. l'8-l), then washing and dyeing in a separate bath for 1— li hour at 100^ C, with 35—50 per cent, of Logwood. This represents the simplest form of dyeing a chi'ome black, but in practice numerous slight modifica- tions are introduced, in order to obtain various shades of black. The following, which are typical, may be men- tioned. The mode just given yields a blive-black, or, as it is sometimes called, a black with blue reflection. By the addition of a suitable amount of some yellow colouring matter to the dye-bath — e.g., 5 per cent. Old Fustic — a 324 DYEING OF TEXTILE FABRICS. [Chap. TTTT. dead-black is obtained, i.e., a neutral black, which possesses no decided tint of blue, green, violet, i;c. By increasing the amount of Old Fustic to 10 per cent., a green-bJficli is obtained, and the greenish shade becomes still more pro- nounced, if 3 — i per cent of alum is added to the mor- danting bath along with the bichromate of potash. A vivM-black is produced by dyeing exactly as for blue black, but after the dye-bath has been exhausted, a dilute solution of about_2 per cent of stannous chloride (tiu crystals), or its equivalent of commercial muriate of tin containing no fi'ee acid, is added to the dye-bath, and the boiling is continued 15 — 20 minutes longer. In the case of dead-blacks, it is the custom with some dyers to " sadden '" in a similar way with 3 — 4 per cent of ferrous sulphate; or instead of this, the goods are passed, after dyeing, through a warm bath containing about 0-5 per cent, of bichromate of potash. The object of these last modifications is to precipitate and fix more completely on the wool any colouring matter, perchance not combined with the mordant, but simply absorbed by the wool With black yarn, which will eventually appear in a woven fabric, in close proximity to white or delicately- coloured yams, this fixing of the dye is very necessary, otherwise the light-coloured or white yams become stained during the operations of milling, ic, and the finished fabric has a soiled appearance. It is always the case that some black comes ofl' during these opei'ations, but if the colouring matter of the Logwood is thoroughly com- bined with its own moi^lant, it will not readily combine with the mordant of any neighbouring fibre, but be simply rubbed or washed out as an insoluble powder. Clirome blacks may also be dyed in a single bath, as follows : A mixtui'e of Logwood liquor and bichromate of potash solution in suitable proportions is boiled. The precipitate thus produced is collected, and may then l^e employed as a " direct black," or a " one-dip dye." It is, indeed, the actual coloured body or pigment one wishes to fix upon the wool, and this is rendered possible, because Chap. Xni.] LOGWOOD. 325 not only is the precipitate soluble in an acid solution, but the wool is capable of attracting it from the solution. The precipitate is added to the dye-bath, along with just suffi- cient oxalic acid to dissolve it, and the wool is dyed in the solution at 100° C, for one and a half hour. Good results are, however, not so readily obtained as when iron and copper mordants are used (see Bonsor's black, p. 329). 259. Indigo Substitute. — This product, at present sold in the form of a purplish-blue liquid, is said to be pro- duced by boiling together Logwood extract and chromium acetate. Cotton is dyed by simply working it in a hot solution of the mixture. Of all the blacks derived from Logwood, the chrome black is the one least affected by acids. If tested by spotting with strong sulphuric acid, it becomes a dark olive colour. It also resists the action of scouring and fulling very well. On the other hand, however, chrome blacks are not altogether satisfactory as regards their behaviour on exposure to light. They gradually assume a greenish hue, although otherwise they are tolerably fast. The greening of a chrome black is most apparent when Logwood, or Logwood and Old Fustic, have been employed in dyeing. Its bad effect may be counteracted by the addition of a suitable red colouring matter to the dye-bath — e.g. Alizarin — or by dyeing the wool a reddish- brown colour before dyeing with Logwood. This is very conveniently carried out in practice by boiling the wool with 6 — 8 per cent, of Camwood for an hour, then adding to the exhausted bath the bichromate of potash (generally with the addition of a small percentage of alum and tartar), and mordanting, &c., as already given. Owing to the comparatively small proportion of bichromate of potash required to produce the fullest blacks, there is evidently a minimum quantity of lake precipitated on the fibre, so that the latter retains very much its pristine elasticity and softness. Excess of bichromate of potash should always be 32G DYEIXr; OF TEXTILE FABRICS. [Cliap. XIII. avoided, since the colour is then more liable to become gi'een, or to fade, on exposure to light. 260. The use of Bichromate of Potash.— The fol- lowing results of expeiiments on the use of chromium mordants will be of interest. By mordanting the wool with 3 per cent, of bichro- mate of potash, a full and bright shade is obtained. The use of more than this amount causes the colour to become dull and gi-ev (over-chroming, see p. 209). The employment of sulphiu'ic acid along with the bi- chromate of potash is advantageous when the proportion does not exceed one molecule of sulphuric acid to one molecule of bichromate of potash, i.e., 1 per cent, of sul- phuric acid 168' Tw. to 3 per cent, of bichromate of potash. T^'hen used in this proportion it gives a brighter and somewhat deeper shade than can be obtained fi'om bi- chi'omate alone : but should the above-mentioned amount be exceeded, a dull grey appearance results, which becomes more apparent as the amount of sulphuric acid increases. If the bichromate of potash be increased along with the sulphuric acid, the injurious effects of " over- chroming " are intensified. The addition of tartar or tartaric acid to the mor- danting bath, along with bichromate of potash, is bene- ficial, the shades being much more brilliant, though somewhat lighter, than when sulphuric acid is used. Tartaric acid gives decidedly brighter and more purple shade.? than tartar. The best results are obtained by using 6 per cent, of tartaric acid or 8 per cent, of tartar to 3 per cent, of bichromate of potash. Oxalic acid is also beneficial in the mordanting bath, and in this case, 4 per cent, of oxalic acid to 3 per cent, of bichromate of potash yields the best results. On comparing the shades obtained by using these acids in the mordanting bath, it is seen that they are all better than can be obtained by bichi'omate of potash alone. The addition of sulphuric acid produces a deep, dead- lool^ing blue-black : tartar or tartaric acid yields a bright Chap. XITT.] LOGWOOD. 327 bloomy bluisli-black ; oxalic acid a black wliicli is darker, duller, and slightly greener than can be obtained with tartar or tartaric acid, but not so dark as with sulphuric acid. Whenever bichromate of potash alone is employed, the mordanted cloth has a dull yellow colour, but if tartar or tartaric acid has been added to the bath, it is a pale bluish-green. From these results it would appear that the best shade is obtained when the chromium mordant is fixed on the cloth in the state of chromic oxide previous to the application of the Logwood. The substitution of chrome alum as a mordant in place of bichromate of potash does not give good results, the ultimate colour obtained having an irregular speckled appearance, evidently owing to the unequal deposition of the chromic oxide ; besides a very large proportion of tartar must be used to obtain a full shade. WTien the cloth has been mordanted with bichromate of potash alone, or with bichromate of potash and sul- phuric acid, the presence of chalk or calcium acetate in the dye-bath is decidedly injurious. The acetate seems to be least hurtful, although, even with this, the addition of more than 2 per cent, gives the colour a greyish ap- pearance. If tartar has been employed along with the bichromate of potash, the presence of calcium acetate is decidedly beneficial, the shade being intensified from a pale blue when no calcium acetate is used, to a deep indigo-blue when 30 per cent, is employed. The best amount to use appears to be 30 per cent., but even 80 per cent, may be added to the dye-bath without any great detriment, the colour merely losing a little brilliancy and pui'ple tone, and becoming blacker. 261. Copperas or Ferrous Sulphate Black.— This black was formerly the one in general use, but since the introduction of the chrome black, it has been more or less discontinued. It is often used for low-class carpet, yams, d:c. 328 DYEING OP Ti:XTILE FABRICS. [Chap. XIII. Two methods may be employed, namely, that of mor- danting the wool first and dyeing afterwards, or that in which the wool is first boiled with Logwood and after- wards saddened. It is usual to add along with the ferrous sulphate a small proportion of copper sulphate, and when the first method is employed, argol, and frequently also alum, is added. Example of first method. — Mordant the wool for 11 — 2 hours with 4 — 6 per cent, of ferrous sulphate, 2 per cent, of copper sulphate, 2 per cent, of alum, 8 — 12 per cent, of argol ; take out, squeeze, and let lie overnight. Dye for 1 J hour with 40 — 50 per cent, of Logwood. ExdmjyJe of second method. — Boil the wool for one hour with a decoction of 40 — 50 per cent, of Logwood, and 5 — 10 per cent, of Old Fustic ; lift^ cool the bath, add 4 — 6 per cent, of ferrous sulphate, and 2 per cent, of copper sulphate, re-enter the wool, raise the temperature to 1 00° C. in three-quarters of an hour, and boil half an hour. The first method is the more economical. The amount of tartar or argol used along with the ferrous sulphate in the first method has considerable influence on the beauty of the colour ; with too little it is grey and dull ; an excess is less hurtful. Experiment shows that the relative proportions should be — 1 molecule of ferrous sulphate, 2 — 3 molecules of cream of tartar. There is no advantage in using more than 6 per cent, of ferrous sulphate. Wool mordanted with ferrous sulphate alone is buff-coloured from deposition of ferric oxide ; when tartar is used its colour remains almost unchanged. If the water employed is not calcareous, the addition of 3 per cent, of chalk, or preferably calcium acetate, to the dye- bath increases the intensity of the colour. The use of a lime salt here does not appear to be so effective as with chromium or aluminium mordants. As with the chrome black, so here the addition of a yellow colouring matter to the dye-bath is necessary in order to obtain a dead-black ; ■without such addition a ferrous sulphate black possesses Cliap. XIII.] LOGWOOD. 329 a bluish-violet, hue. The addition of relatively small pro- portions of Madder, Sumach, &g., aids in giving a fuller and faster black. Sumach, or other tannin matter, when used alone, is incapable of giving a black on wool with ferrous sulphate. When dyeing unspun wool or yarn it is preferable to use a freshly-made decoction of Logwood, or a good com- mercial Logwood Extract, in order to keep the material clean and free from ground dyewood, since this would interfere in the carding. The ferrous sulphate blacks become red if spotted with strong mineral acid, and are thus readily dis- tinguished from chrome blacks. They bear the action of scouring and milling satisfactorily, and withstand the action of light better than the clu'ome blacks. Experi- ment proves that with regard to fastness against light a simple copper sulphate black is the best, so that the use of copper sulphate along with the ferrous sulphate or potassium dichromate is distinctly beneficial. The use of alum is, on the contrary, detrimental in this respect. The copper sulphate will probably also aid in developing a fuller black by reason of its oxidising action upon the hsematoxylin. "When employed alone, copper sulphate gives greenish shades of blue, having a slightly speckled appearance. The best proportions to employ appear to be 5 per cent, of copper suljDhate, and 5 -5 per cent, of tartar. An excess of tartar causes the shade to become much lighter. With these amounts, and varying the quantity of Logwood, a series of shades, ranging from pale blue to black, may be obtained, but the lighter shades have a distinct greenish appearance when examined overhand not ob- servable in the darker shades. The mordanting and dyeing method yields the deepest and most useful shades. The addition of lime salts to the dye-bath is only slightly beneficial. 262. Bonsor's Black.— This "direct black," originated by P. Watinne-Delespierre of Lille, consists of a black '?,30 DYEING OF TEXTILE FABRICS. [Clifip. XDI. paste, produced by precipitating a decoction of Logwood with a mixture of ferrous and copper sulphate. It is applied in the same way as the direct chrome black already referred to. Add to the dye-bath 25 — 30 per cent, of the black paste, and about 2 — 3 per cent of oxalic acid. The wool is dyed at 100° C. for 1—2 hours. It is essential that the solution should not be too acid, or it will not yield its full colouring power. The normal colour of the solution is dark-brown; if blue or green in tint, it is a sign of the presence of undissolved precipitate, and a further slight addition of acid must be made. As the dyeing proceeds, the solution necessarily becomes more and more acid, and it is well before taking out the wool to add a small quantity of sodium carbonate, to neutralise the excess. If a deeper shade is wanted, one may add along with the black paste some extract or decoction of Logwood. For a jet-black or dead-black some suitable yellow colour- ing matter may be added in small quantity, e.g., Old Fustic Extract, e object of using aluminium mordant is to impart ultimately to the silk a violet or blue-black shade. 7. Dye with Logwood and soap. If the shade is too violet, a little Old Fustic is added. 8. Brighten. VI. — Mineral Black (dating from 1840). — This is a light black, not so fine as the last, and is used for " linings." Mordant with basic ferric acetate, and wash; dye Prussian Blue ; repeat the mordanting with iron. Prepare with Catechu (100 per cent.) at 80° C. Dye with Logwood and soap. Brighten. C. Black on boiled-off Silk, weighted 20 — 100 per cent, (heavy black). VII. — This black is dyed on organzine and tram for satins, sarcenets, tafietas, &c. 1. Mordant Avith basic ferric sulphate, then soap. Bepeat these operations 1 — 8 times, according to the amount of weighting necessary. 2. Dye blue ; the propoitions of potassium ferro- Chap. XnL] LOGWOOD. 335 cyanide and liyckocLloric acid vary according to the amount of fen'ic oxide fixed on the silk. 3. Give a Catechu bath (100 — 150 per cent.), mth the addition of 10 — 15 per cent, stannous chloride, at 60^—80^ C. The employment of stannous chloride in weighted black-silk dyeing has been of the gi'eatest impor- tance, since it facilitates the fixing of the Catechu to a sui'prising degree, through the formation of a tannate of tin. 4. Give a second bath of Catechu (100 — 200 per cent,). This is fijced on the silk only by the action of the tin mordant present. 5. Mordant with pyrolignite of iron. 6. Dye "with Log^vood and soap. 7. Brighten. Blue shades of black are obtained by repeating operations 5, 4, 6, in the order given, four times. The only factoi*s which aftect the limitation of weighting are the strength, elasticity, and lustre of the silk itself. A.S a rule, boiled-off organzine is weighted to 60 — 70 per cent., and boiled-off tram to 100 per cent. D. Heavy Black, weighted to 400 per cent VIII. — This is used for fringes and the fancy articles of Paris and Lyons ; also for the tram silk for satin, cheap ribbons, &c. The raw-silk is dyed by working it alternately in chestnut extract and pyrolignite of ii'on. By repeating these operations fifteen times, the silk is weighted to about 400 per cent. The final processes consist of brightening operations with 10 — 20 per cent, of olive-oil. In the first chestnut extract bath, ti-am is soupled by raising the temperature of the bath sufficiently to soften the silk- glue. Different qualities of silk requii-e slightly different treatment. Bengal silk souples easily ; Chinese silk less readily than European silk. 336 DYEING or TEXTILE FABRICS. LClmp. XIIL E. Fixe Black Souples. IX. — The finest souples are always obtained by using wai;b& as soft as possible, Kke that of the Gier at Saint-Chamond- 1. Mordant with basic ferric sulphate. 2. Give a soda bath at 30°— 40° C. TJse 50 per cent of carbonate of soda crrstals. 3. Dye blue with potassium ferrocyanide. 4. Souple by working in a bath of gall-nuts, dividivi, or other similar tannin matter. Heat the bath to 90° — 95^ C, for 1 — 3 hours, according to the kind of ^Ik. Experience alone enables the workman to judge when the softening or soupling is sufficient. 5. Leave the silk in Is"©. 4 bath until cold, and then add 5 — 15 pa* ooit. of stannous chloride crystals. e. Give a soap bath at 30°— 35° G, with 60—80 per oQit. of soap. 7- Britten with 5 — 15 per cent of oiL A single iron bath gives 40 — 50 per cent, of weighting (light souple) ; two baths give 60 — 70 per cent. ; three give 80 per cent ; four give 80 — 100 per cent. F. Black on PlAW-Silk. X. — This is seldom dyed. In order to retain the stiff- ness of the silk, the silk-glue is not softened, the number of opoations is as limited as possible, and the various baths are used at a low temperature. Tlie process consists of ■working the silk in baths of ferric salt, then in decoctions lacement of Madder by Alizarin in Turkey-red dyeing has not necessarilv brought about anv material chansjes in the mode of cariying out this preliminary oiling process, so that the Emulsion and Steiner's processes {see pp. 427, 438) may be taken as representing essentially the method of dyeing Turkey-red adopted in the days when Madder was employed, substituting merely an equivalent amount of ground Madder for the Alizarin. 276. Apjjlicatioi to Wool. — ^Vhen wool is boiled ^\T.th Madder it acquires a pale browTi or drab colour, and although this can only be considered a stain, this simple method of application has been adopted in practice. By mordanting the wool previously with 3 per cent. oihichromate of potash^ good reddish-browns are obtained. The addition of 1 per cent, of sulphuric acid, or 9 per cent. of tartaric acid, gives a darker colour. By the " single- bath method " fairly good colours are obtained ; they are, however, yellower and not so deep as those yielded by the ordinary method. For red, the wool is mordanted with aluminium sul- phate and tartar, and dyed with Madder in a separate bath. Mordant the wool with 6 — 10 per cent, of aluminium sulphate and 5 — 8 per cent, of tartar. Dye with 60 — 80 per cent of Madder. Begin the dyeing at 40° C, and raise the temperature of the bath gradually 346 DYEIXG OF TEXTILE FABRICS. [Chap. XIV. to 80° — 100° C. in the course of one hour, and continue the dyeing about one hour longer. Wash and dry. The shade thus produced is a brownish-red. It may be made considerably brighter, and of an orange tone, by adding a small proportion of stannous chloride solution along with the aluminium sulphate and tartar ; or instead of this^ the stannous chloride may be added to the dye- bath towards the end of the operation. The gradual raising of the temperature of the dye- bath is essential in order to develop the full colouring power of the Madder. If the bath is allowed to cool considerably or frequently during the progress of the dyeing, even though the correct temperature is con- tinually re-established, there is a loss of colouring power. If the water or ]Madder used, is deficient in lime, brighter and fuller shades are obtained by an addition to the dye-bath of 1 — 2 per cent, (of the weight of Madder employed) of ground chalk, or acetate of lime. This addition is useful with Dutch and Alsatian madders, since these are naturally deficient in lime. The addition too of a small proportion of tannin matter alonor with the Madder serves to exhaust the bath more fully and to give deeper shades. Add Sumach, say, to the amount of one-tenth of the weight of Madder employed. Avoid an excess, since it gives a poor weak colour. Brighter shades are obtained by employing the lower temperature given (80° C.) and prolonging the dyeing process, because in this case the yellow and fawn-coloured principles of the Madder are not so readily fixed. After dveing and washing;, the colour mav be made somewhat brighter by working the wool for a short time at 70° C. in a bath containing either a small proportion of soap solution, or of a decoction of bran. With thick woollen materials it happens sometimes that the colour does not penetrate sufficiently. To over- come this defect it is usual to add a small portion of Madder to the mordanting bath, so that at least some of the colouring matter of the Madder may penetrate to the Cliap. XIV.] MADDER. 347 centre of the fabric before it is precipitated and fixed by the mordant. It is quite possible, indeed, to dye lioht shades with the Madder and mordant in the same bath but this method is not applicable if the fullest and richest colours are required. Under the most favourable conditions a Madder red on wool is by no means brilliant, and not to be compared m this respect with Cochineal scarlet. It is, however a tast and permanent colour, and withstands the action of light and milling with soap extremely well. Since the introduction of artificial Alizarin, fast reds should be dyed with this colouring matter in preference to Madder, since brighter colours are obtained at a less cost Wool mordanted with 8 per cent, of stannous chloride and 4 per cent, of tartar, and dyed in a separate bath cent fenOl 2YL,0 and 2 per cent, tartaric acid. _ VVith copper sulphate and tartar, brown-colours are ob- tained ; with ferrous sulphate and tartar, darker browns Usetwo-bathmethod; single-bathmethodisalso applicable ^77. ^;^;^W^on^o^^7^^— Notwithstanding the ^ene. ral fastness of the colours produced by Madder, olin. ma^^^^r -fk^S^ ''^ ^^— ^^ -P-ti.ely :For red the silk is morcWted as usual with alum by steeping over-mght m a cold concentrated solution. Wash weJ and dye in a separate bath with 50 per cent of finely ground Madder. Begin dyeing at a low tempera ture and raise it gi^adually to 100° C. The addition of bran to the bath tends to give brighter colour" Fo" add to the dye-bath a small percentage of Sumach. After dyeing, wash, then brighten in a boiling solution of soap to which a small percentage of stannous chloride has been added, and wash well. By mordanting with /errors sulphate, either alone or after a previous mordanting with alum, violet and brown shades may be obtained. 348 DYEING OF TEXTILE FABRICS. [Chap. XIV COCHINEAL. 278. This colouring matter consists of the dried insect Coccus cacti, largely cultivated in Mexico. It is little used in cotton-dyeing, except by the calico- printer. Formerly much employed in silk-dyeing, it has now been almost entirely replaced by the use of various aniline-reds, while in wool-dyeing since the introduction of tlie azo-reds its use has become more and more limited. 279. Application to wool. — Wool mordanted with 2 per cent, of bichromate of potash, and dyed in a separate bath with Cochineal, gives a good purple colour. The ad- dition of sulphuric acid to the mordanting bath, even to the extent of 3 per cent, of H^SO^ 168° Tw., makes the colour darker. Two different shades of red are obtained from Cochi- neal, namely, a bluish red, called crimson, and a yellowish or fiery red, called scarlet. 280. Cochineal Crimson is obtained by mordanting the wool with 4 — 8 per cent, aluminium sulphate and 5 per cent, of tartar, and dyeing in a separate bath with 8 — 15 per cent, of Cochineal. The addition of lime salts to the dye-bath is not beneficial. Fairly good shades are obtained in a single bath by using 6 per cent, of alumi- nium sulphate and 4 per cent, of oxalic acid or 6 per cent, of potassium oxalate. Cochineal crimson can, how- ever, be obtained in a variety of ways. One method is to dissolve about 5 per cent, of alum, and 2 J per cent, of tartar in an old Cochineal-scarlet bath, and boil the wool about one hour in it ; then dye at the boil for half an hour in a separate bath, with 10 — 15 per cent, of Cochineal. The following table gives the proportions of other materials which may be employed : No. 1. Tartar, per cent. 6 SnCls SnClj (crystals) (crystals) per cent, per cent. 3 3 Alum, sulphate per cent. 10 CochineaJ. per cent. 8 to 15 Wool. 100 2. 3. 4 1 2 1-6 1 5 M M Chap. XrV.] COCHINEAL. 349 Boil 1—1 1- hour with the mordants, and dye in a separate bath with the Cochineal for 20 — 40 minutes at 100" C. Good crimsons may also be obtained in one bath by boiling the wool for i— | of an hour with the aluminium sulphate and tartar, then removing it temporarily to add the ground Cochineal, boiling a few minutes, and finally re-entering the wool and boiling -| — |- of an hour longer. A certain proportion of the colouring matter ahvays°re- mains precipitated in the bath and is lost by this method. In order to modify the shade of crimson and make it still bluer, a small amount of carbonate of soda or liquid ammonia is sometimes added to the dye-bath towards the end of the dyeing operation, or the goods are washed in water and made slightly alkaline by the addition of a little lime-water. Other modifications of shade are obtained by adding to the dye-bath varied proportions of Ammoniacal Cochineal, Orchil, or Cudbear ; these, how- ever, produce a colour which is not so fast towards light. Ammoniacal Cochineal is frequently used along with ordinary Cochineal for the production of rose-pinks, i.e., bluish shades of pinks. Cochineal crimson obtained by using aluminium mor- dant is tolerably fast to light, and also to milling with soap and weak alkaline carbonates. 281. Cochineal Scarlet— The ingredients generally used in obtaining this colour are Cochineal, a stannous salt, and cream of tartar, or oxalic acid. Two distinct methods for its production maybe adopted, (1) the wool is first mordanted with the stannous salt and tartar, and then dyed in a separate bath with Cochineal; (2) the mordanting and dyeing are performed simultaneously in one and the same bath. First Method. — Mordant the wool for 1 11 hour with 6 per cent, of stannous chloride (crystals) and 5 per cent, of cream of tartar, and wash. Dye with 5—12 per cent, of ground Cochineal for 1 — 1| hour. In order to obtain level shades, enter the wool both in the mor- 350 DYEING OF TEXTILE FABRICS. [Chap.XIV. danting- and dye-bath at about 50° C. and raise the tem- perature gi'-adually to the boiling point. If 3 per cent of the stannous chloride is replaced bj its equivalent of stannic chloride, the colour is yellower and more brilliant (Liechti). The addition of lime salts to the dye-bath is injurious. Second Method. — Fill the dye-bath half full of water, add 6 — 8 per cent, of oxalic acid, 6 per cent, of stannous chloride, and 5 — 12 per cent, of ground Cochineal ; boil up for 5 — 10 minutes, then fill up the dye-bath with cold water. Introduce the woollen material, heat up the bath to the boiling point in the course of | — 1 hour, and boil \ hour. Potassium oxalate may replace oxalic acid ; or one may use with advantage the mixture of stannous and stannic chloride with tartar as given above. By this " single-bath method " the dye-bath is not ex- hausted as in the fii-st method ; a portion of the colouidng matter always remains in the bath in combination with the mordant as a yellowish flocculent precipitate. The unexliausted bath may, however, be utilised for one or two succeeding lots of material, by merely re- plenishing it with further quantities of the several in- gredients. In practice many modifications have at one time or another been introduced into Vjoth the above methods. In the first, for example, the mordant has been divided, adding a portion only, to the actual mordanting bath, and the remainder to the dye-bath along with the Cochineal, This division has extended either to both tartar and stan- nous chloride or to one of these only. Sometimes, too, the Cocliineal has been divided, a small proportion being added already to the mordanting-bath. Washing between mordanting and dyeinsr, not being absolutely essential, has been omitted. The temperature and duration of mordanting and dyeing have varied greatly ; and other stannous and stannic salts, with the addition of other assistants than tartar, have been employed The changes rung on the variations possible in the second method have been almost equally numerous. Chap. XI v.] COCHINEAL. 351 Comparing the two methods, experiment shows that, with an equal expenditure of ingredients, the first method gives a blue shade of red possessing both purity and intensity of colour. The single-bath method gives a yellower and more brilliant scarlet. This method is on the whole the more advantageous, and is the one gene- rally adopted. When the single-bath method is employed, compara- tively little difference is produced by di%i.ding the mordant and reserving a portion to be added along with the Cochi- neal during the second period of the process. If the addition is mainly or entirely confined to the first or mordanting period, the scarlet obtained is slightly more intense and yellower. Without the use of tartar a poor bluish shade of red would be obtained. Addition of tartar up to 8 per cent, increases the intensity and yellowness of the colour. A deficiency of tin mordant gives also a dull bluish- red, while an excess makes the scarlet paler. As a rule, stannous chloride is not employed in the crystalline state — i.e., as "tin-crystals" — but in the form of an acid solution, namely, as " double or single muriate of tin." The presence of a moderate excess of free hydrochloric acid in these solutions has the followino; advantages : — 1. The mordant is thereby rendered less sensitive to decomposition, and is better able to penetrate thick, closely-woven or hard-spun material before any deposition of mordant takes place. The material thus becomes more thoroughly mordanted throughout its mass, the ultimate colour is not so much confined to the surface, and the material appears dyed through. 2. The free acid present, acts beneficially by retaining the coloured lake already alluded to longer in solution, so that the wool acquires a deeper shade than it would otherwise. 3. The presence of free acid in the dye-bath is abso- lutely essential, when a calcareous or otherwise alkaline 352 DTEiyC OF TEXTILE FABRICS. [Chap. XIV. ■water is employed, unless the latter is previously neu- tralised : or when after scouring the wool with weak alka- line solutions the washing has been insufficient. Without the free acid, the mordant would be precipitated in the bath to a greater or less deo^-ee, according to the alkalinity of the water, and the scarlet would either be of a weak, dull-bluish shade, or might not even be produced at all. In dyeing Cochineal scarlet, therefore, an acid condition of the bath is essential to the production of a satisfactory colour. A large excess of free acid, however, must be avoided, otherwise the colour lacks intensity. Other salts of tin, known as Tin Spirits, Scarlet Spirits, <$:c, are often used instead of those ali-eady given. The first-mentioned solution, or " nitrate of tin," is much used by dyers. The scarlet it yields has a decided yellow shade, owing probably to the action of the nitric acid liberated during the mordanting process. In this respect, therefore, it is equivalent to an extra addition of tartar. Although stannic chloride, when used in conjunction with tartar and Cochineal, yields fairly good scarlets, these cannot compare in brilliancy with those obtained by the use of a mixture of stannous and stannic chloride. The presence of a certain amount of stannic salt along with stannous chloride is said to be beneficial in preventing the production of so-called " tin spots," i.e., dark-lookins: or almost black spots, which sometimes occur in-egularly throughout the scarlet-dyed fabric. These spots consist of anhydrous stannic oxide, produced from the hvdrate sta,nnous oxide during the boihnsr. The use of oxalic acid acts beneficially in the same direction. In order to obtain bright yellow shades of scarlet, it is usual to add a small proportion of some yellow colour- ing matter along with the cochineal Flavin, or Young Fustic, are generally used for this purpose. Persian Berries are occasionally used, but they are more expen- sive. Cochineal red on wool must be considered as very Chap. XIV] COCHINEAL. 353 fairly fast to light. Its principal defect is that by the action of weak alkalis, soap, taining reds similar to those yielded by Cochineal, and the methods adopted are essentially the same as those already described. Owing to the presence of a large excess of mineral and resinous impurities, Lac-dye yields its colour- ing matter to water less readily than Cochineal ; hence, twelve hours or so before it is added to the dye-bath, it should be gi-ound and made into a paste with the tin solution to be employed, sometimes with the addition of a little free hydrochloric acid. This preliminary treat- ment softens the Lac-dye, dissolves part of the mineral matter with which the colouring matter may be com- bined in the form of a lake, and thus renders it more soluble in the dye-bath. With the exception of this slight deviation, the dyeing is performed in exactly the same manner as with CochineaL Lac-dve reds are less brilliant than Cochineal reds, but possess greater intensity. They are also considered to be somewhat faster to light and wear, and to the action of milling with weak alkaKs. Hence Lac-dye is frequently used in conjunction with Cochineal, in order to take advantage of the good qualities of both, and thus obtain a colour which combines fastness and brilliancy. To this end the two dye-stufis may be added to the same dye-bath ; or better still, the material is first dyed with Chap. XIV.] ORCHIL AND ANNATTO. 355 Wdye and afterwards with Cochineal, in a separate ORCHIL. 284 —Orchil paste, Orchil extract, and Cudbear are prepared from certain lichens bj submitting them to a process of oxidation in the presence of ammonia They are still much used in the dyeing of compound shades on wool and silk. Their colouring matter (Orcein) dyes best m a neutral bath, but it possesses the very useful pro- perty of dyemg either in a neutral, slightly alkaline, or slightly acid bath, and the colours have an intensity or body not readily obtainable by means of its rivals amon<. the coal-tar colours, chief among which is Fast Red o? Koccellme. The colour is not fast to light. Orchil is not applicable in cotton-dydng, and for wool and silk no mordants are required. Application to IFoo^.—Dyein a neutral bath, or with a slight addition of sulphuric acid, or of soap solution Application to Silk.~-Dje in a bath containing soap solution, or boiled-off liquor, with or without the acfdition of acetic or sulphuric acid. The colour produced is a bright bJuish-red or magenta. ° ANNATTO. 285.— This colouring matter is obtained from the pulp surrounding the seeds of Bixa orellana. Owino- to the fugitive character of the red or orange colour which It yields. Its employment is very Hmited, and is chietiv confined to silk-dyeing. A short time before it is re- quired for use, it must be dissolved by boiling it with a solution of carbonate of soda. Application to (7o«o7^.— Work the cotton in a hot solution of Annatto, containing soap or carbonate of soda Pale colours are dried direct from the dye-bath ; dark colours should be rinsed slightly in a cold soap solution to remove excess of alkali from the fibre. By passing the dyed cotton through water slightly acidulated with sulphuric acid or alum, the colour assumes a redder tint 356 DYEING OF TEXTILE FABRICS. [Chap. XV. Apjjlication to Wool and Silk. — Pale shades are dyed at 50° C, with the addition of soap to the bath; dark shades are dyed at 80° — 100° C, without any addition. SAFFLOWER. 286. — This dyestufF consists of the dried florets of the composite flower of Carthamus tinctorius. Pre\T.ous to being used by the dyer the commercial product should be well washed with cold water to remove the worthless yellow colouring matter present. It is best to use the so-called Safflower-ex tract. Safflower finds a very limited use in the dyeing of cotton yarn, thread, and tape. The bright pink colour obtained is extremely fugitive. A2?pIicatio7i to Cotton. — To ensure even dyeing the cotton is first worked for some time in a cold carbonate of soda solution of the colouring matter ; it is then removed from the bath, and the solution is slightly acidi- fied with sulphuric, acetic, or tartaric acid. The cotton is again introduced, and worked about until the bath is exhausted. The real dyeing only takes place in the acid bath. The dyed cotton is afterwards rinsed in water slightly acidified with acetic acid or cream of tartar, and dried in a cool, dark place. Silk may be dyed in a similar manner. CHAPTER XV. YELLOW COLOURIXG MATTERS. WELD. 287. — Weld consists of the plant Reseda luteola. It is principally used in wool- and silk-dyeing, for producing yellow and olive colours. 288. Application to Cotton. — The yeUow colours ob- tained on cotton fi-om this dyestufi" are of little or no importance, since they are not fast to soap. Oxap. XV.] "U-ELD. 357 Chromium mordants yield yeJlowish olives, very fast to soap and light. The addition of calcium acetate to the dye-bath is beneficial With aluminium mordants yellows are obtained, but they possess no particular brilliancy. Work the cotton in aluminium acetate 4° — 6° Tw, (Sp. Gr. 1-02 — 1"03), and fix in a separate bath with phosphate or silicate of soda ; wash and dye for \ — j of an hour at 60= C. A slight addition of acetate of copper to the dye-bath makes the shade more orange. With stannic mordants the yellows produced are slightly faster to soap, and somewhat more orange in tone. Fyrolignite of iron as the mordant, with or without the additional use of aluminium acetate, and fixed by means of silicate of soda, gives various shades of olive. Greens are obtained by mordanting wdth aluminium, and dyeing with a mixture of Weld and Logwood, or by first dyeing the cotton an indigo- vat blue, afterwards mordanting with aluminium acetate, or a stannic salt, and dveing with Weld. 289. Application to Wool. — The use of Weld in woollen- dyeing is limited, because it is of low colouring power and requires two baths, and because the fastness and purity of the yellow colour are not generally recognised. Wool mordanted with 2 per cent, of bichromate of potash, and dyed in a separate bath with 60 per cent, of Weld, .gives an olive-yellow or old-gold shade. The addi- tion of sulphuric acid to the mordanting bath is not beneficial. The addition of 3 per cent, chalk to the dye- bath adds intensity to the colour. To produce Weld yellow, mordant the wool by boiling it 1 — 2 hours with 4 per cent, of aluminium sulphate, wash and dye in a separate bath with a decoction of 50 — 100 per cent, of Weld, for 20—60 minutes, at 80° — 90° C. The dye-bath is prepared immediately before intro- ducing the mordanted wool, the chopped Weld being en- closed in weighted bags, and boiled ^vith soft water only, for \ — 1 hour, then add 4 per cent, chalk before dyeing. 358 DYEING OF TEXTILE FABRICS. [Chap. XV. The colour thus obtained is a yellow comparatively free from any tinge of redness. Its fastness to light and to milling with soap and weak alkalis is very satisfac- tory ; indeed, it must be considered as superior to all other natural yellow colouring matters in these respects. The addition of 5 per cent, tartar to the mordanting bath is beneficial, but excess makes the colour dull. The addition of 2 per cent, of stannous chloride gives bril- liancy and fastness to the colour produced. The addition of 4 per cent, of chalk to the dye-bath gives a yellow, which possesses greater intensity but less purity. The addition of calcium acetate has the same effect as that of chalk, but in a less degree. Brighter yellows are obtained by mordanting with 8 per cent, of stannous chloride instead of with alumi- nium sulphate. By adopting the " single-bath " method similar to that given for Cochineal scarlet, very good bright yellows are obtained. Wool mordanted with 6 per cent, of copj)er sulphate^ and dyed in a separate bath with Weld, gives a yellowish olive colour. The addition of tartar to the mordanting bath is not beneficial. Add 2 — 8 per cent, chalk to the dye-bath. Wool mordanted with 4 per cent, of ferrous sulphate and 3 per cent, of tartar, and dyed in a separate bath with the addition of chalk, gives good olive colours. 290. Application to Silk. — Of all the natural yellow colouring matters, Weld is the most important to the silk- dyer, since the colours it yields are relatively fast to light and slight soaping. It is principally used for dye- ing yellow, olive, and green. For yellow, the silk is mordanted in the usual manner with alum, washed and dyed in a separate bath at 50° — 60° C. with a decoction of 20 — 40 per cent, of Weld. A small quantity of soap solution is added to the dye- bath, in order to ensure even dyeing. The amount to be added increases with the degree of hardness of the water, Chap. XV.] OLD FUSTIC. 359 and the percentage of weld employed ; in any case, the addition of too much should be avoided. It is, of course, better to correct the water previously. After dyeing, the colour is brightened by working the silk for ten minutes in a fresh soap bath to which, in order not to im- poverish the colour, a little decoction of Weld has been added. Wring out without washing. If scroop is re- quired, the silk is washed, and then worked for ten minutes in water slightly acidulated with acetic acid. It is essential to the production of bright yellows that the aluminium salt used be absolutely free from iron. The best Weld to employ is the short French Weld from Cette, and the purest yellows are obtained from the first and second decoctions of the flower portion of the stem. The root portion contains a little tannin matter, which tends to dull the colour. Dark shades of yellow are dyed in the same way, using proportionately more Weld (50 — 70 per cent.). The addition of soap to the bath is not necessary, but it is advisable to keep the temperature somewhat lower. For very dark shades it may be necessary to dye in two Weld baths. Yery often, before wringing, the silk is worked at 60° C. in a strong soap bath, containing a little Annatto, in order to give a slightly more orange tint, as well as additional brilliancy. Full orange colours are produced by first grounding with Annatto, afterwards mordanting with alum, and dyeing with Weld. OLD FUSTIC. 291. This dyestuff consists of the wood of Morus tinctoria. It is principally used in woollen-dyeing, also to a limited extent in silk-dyeing. 292. Application to Cotton. — Old Fustic is but little used by the cotton dyer, the colours it produces on cotton not being fast to soap. The same methods of application as for Weld may be employed. 293. Application to Wool. — In the heavy woollen trade, 360 DYEING OF TEXTILE FABRICS. [Chap. XV. this is perhaps the most largely used of all the natural yellow colouring matters, but principally along with other dyewoods for the production of various compound shades, e.g., browns, olives, drabs, &c. With bichromate of potash as the mordant, it gives a pleasing brownish or olive-yellow colour (old gold). Boil the wool for 1 — \^ hour with 3 — 4 per cent, of bichromate of potash, wash, and dye in a separate bath for 1—1 J hour at 100° C. with 20—80 percent, of ground Old Fustic. By increasing the amount of mordant deeper colours are obtained, but it is not advisable to use more than that indicated. The addition of tartar or sulpliuric acid to the mor- danting bath is not beneficial. With aluminium mordant Old Fustic gives yellow colours, which differ in brightness, according as the dyeing is done in one or two baths. The " sinsrle-bath '' method gives the brightest shades. Dye for 1 — 1^ hour with 4 per cent, of aluminium sulphate, 2 per cent, of oxalic acid, and 20—40 per cent, of Old Fustic, at S0°— 100° 0. The addition of tartar intensifies but dulls the colour. When two baths are employed, mordant the wool for 1 — 1|- hour with 8 per cent, of aluminium sulphate, wash, and dye in a separate bath for ^ — | hour, at 80° — 90° C, with 20—40 per cent, of Old Fustic. Here, too, the addition of tartar to the bath is not beneficial. By using 2 — 3 per cent, of stannous chloride along with the aluminium sulphate, much brighter colours are obtained. The brightest and fastest yellows obtainable from Old Fustic are produced with the use of a stannous mor- dant. Mordant the wool 1 — 1^ hour with 8 per cent, of stannous chloride (crystals), and 8 per cent, of tartar ; wash, and dye in a separate bath for 30 — 40 minutes, at 80—100° C, with 20—40 per cent, of Old Fustic. Very bright yellows are better obtained by adopting the " single-bath " method given for Cochineal scarlet, possibly because then the lime compound of the colour- ing principle " morin " is decomposed. Use 40 per cent. Chap. XV.] OLD FUSTIC. 361 of Old Fustic, 8 per cent, of stannous chloride, 4 per cent, of tartar, and 2 per cent, of oxalic acid. By using less mordant fuller colours are obtained, but they are not so bright. Prolonged dyeing must always be avoided, especially when dyeing at 100° C, or when two baths are employed, otherwise the yellows become dull and brownish, owing to the presence in Old Fustic of a considerable amount of tannin matter. This effect can be obviated to a large extent by adding a solution of glue to the dye- bath, in the proportion of 4 — 8 per cent, of the weight of Old Fustic employed. Stannic chloride, in conjunction with Old Fustic, gives light-brown or fawn colours, and is not a suitable mordant. All the yellows obtained from Old Fustic change to a dull brownish colour after one month's exposure to sun- light, but they bear milling with soap and weak alkalis fairly well. With coppe7' sulphate mordant Old Fustic yields olive colours. Either the " mordanting and dyeing " method, or the " single-bath " method may be adopted. Use 4 — 6 per cent, of copper sulphate and — 4 per cent, of tartar. With 8 per cent, ferrous sulphate and 3 per cent. tartar, darker olives are obtained. The " single-bath ' method gives good and level colours. Use 4 — 8 per cent, ferrous sulphate, without the addition of tartar. 294. Application to Silk. — Old Fustic is still used in silk-dyeing for the purpose of obtaining various shades in 2:reen and olive. It is now seldom or never used for dyeing yellows, since they cannot compare in brightness with those derived from Weld, or from some of the coal- tar colouring matters. It is occasionally used in conjunction with other colouring matters for obtaining compound colours, or for modifying the shade of certain blacks. If required for a light yellow, the silk is worked for J — I" hour, at 50° — 60° C, in a bath containing 16 per 362 DYEING OF TEXTILE FABRICS. [Chap. XV. cent, of alum, and a decoction of 8 — 16 per cent, of Old Fustic. For dyeing a darker yellow — requii'ed, e.g.^ when pro- ducing in conjunction with indigo-vat blue the so-called " fast-green " — the silk is mordanted with alum, washed, and djed for about an hour, at 50=' — 60"*, with a decoction of 50 — 100 per cent, of Old Fustic, and then washed. The colour may be rendered brighter and faster by working the silk afterwards in a cold solution of nitro- muriate of tin, at 4^ Tw., for an hour, and then washing. QUERCITRON BARK. 295. — This dyestuff consists of the inner bark of Quercus tinctoria. Its dyeing properties are so similar to those of Old Fustic that the same methods of applica- tion may be used for both. 296. Application to Cotton. — The colours produced on cotton by means of this dyewood are yery similar to those obtained from Weld, and the same methods of application may be adopted. Quercitron yellow on cotton w^hen dyed with Malachite Green gives very good yellowish-green shades. 297. Application to Wool. — With bichromate of potash mordant, Quercitron Bark gives somewhat redder olive- yellows than those yielded by Old Fustic. Mordant "svith three per cent, of bichromate of potash, without the addi- tion of sulphuric acid or tartar, and dye in a separate batli. The aluminium yellows are paler, while those produced by stannous chloride are very much brighter and more orange in shade than the corresponding Old Fustic colours. With stannic chloride^ Quercitron Bark gives a very pale buff colour. In all cases prolonged dyeing is injurious, and gives dull shades. The addition of glue solution to the dye- bath is beneficial, since it precipitates the tannin matter invariably present. The resistance of Quercitron Bark colours to light C^P'^y^.] QUERCITRON BARK. 363 and milling is about the same as that of those yielded by Old Fustic. It is not extensively used in woollen dyein^r, having been largely supplanted by Flavin. *' 298. Application to Silk. — Quercitron Bark is seldom used alone in silk-dyeing. If required, it may be applied in the same manner as Weld or Old Fustic. Its principal use is for obtaining a dead-black, a small quantity of its decoction being added to the Lo<>wood dye-bath. FLAVIN. 299. — This dyestuff is a preparation of Quercitron Bark, ^ and consists essentially of " quercetin." " Quer- citrin" may also be present in some products. It has occasionally been sold under the name "Auran- tine." The advantages which Fla^^n has over Quercitron Bark are, that it is verv- much stronger in colouring power, and being free from tannin matter it yields brighter shades. A good quality of Flavin may possess sixteen times the colouring power of Quercitron Bark, but very inferior qualities are frequently met with So- called "Patent Bark," prepared by boiling gi'ound Quercitron Bark with sulphuric acid, is an excellent substitute for Flavin in wool-dyeing. Flavin is not used in cotton-dyeino'. 300. Application to Wool. — When employed for yellow tm mordants, with or without the addition of aluminium sulphate, are used. With aluminium mordants alone comparatively pale yellows are produced. With stan- nous mordants the yellows are verv much richer, and of a more orange tone. With stann^ic mordant pale yel- lowish buffs are produced. In dyeing Flavin yellows it is most advantageous to mordant and dye in one bath, after the manner recom- mended for dyeing Cochineal scarlet. By this means brighter colours are obtained. Boil the wool for 1—3 of an hour with 4—8 per cent, of stannous chloride (crystals), and 0—4 per cent, of tartar; take out the wool temporarily ; add 1—8 per cent, of Flavin ; boil five 364 DYEING OF TEXTILE FABRICS. [Oiap. XV. to ten minutes ; re-enter the wool, and continue boiling for half to one hour. It is well to mix up the Flavin with a little hot water to form a smooth paste, before addinj!^ it to the dye-bath, since it tends to form lumps not readilv wetted and dissolved, if thrown into the bath in the diy state- Increase of stannous chloride adds intensity and redness to the colour. Acid solutions of stannous chloride or nitrate of tin mav be used instead of stannous chloride crystals. Increase of tartar reduces the intensity, brilliancy, and redness. The tartar may be partly or entirely replaced by 2 — i per cent, of oxalic or tartaric acid, when, indeed, brighter shades result. Increase of Flavin adds intensity and redness. With 1 per cent, of Flavin the shade produced is a bright canary-yellow ; with 8 per cent, it is a bright orange. Flavin yellows and oranges on wool, obtained by means of stannous mordants, are among the brightest that can be produced from either natural or artificial colouring matters. With regard to their fastness to light and milling with soap and dilute alkalis, they behave the same as those of Quercitron Bark and Old Fustic, becoming brownish. Flavin is much used along with Cochineal for dyeing scarlet. 301. Application to Silk. — Flavin is not generally used in silk-dyeing. It may, however, be applied in the same manner as Weld. YOUNG FUSTIC. 302. — This colouiing matter consists of the wood of the sumach tree {^Rhus cotinus). Owinor to the fuodtive character of all the colours produced by this dyestuff, it is of little or no use to the cotton and silk dyer, and it would be no great loss if it disappeared from the market altogether. It was^ Chap. XV.] YOUNG FUSTIC. 365 however, mucli used formerly in dyeing brown colours on silk, the yarn being mordanted with alum and after- wards dyed with a decoction of Young Fustic, Peach- wood, and Logwood. It still finds a limited use in wool-dyeing for the production of orange or ycarlet. 303. Application to Wool. — Wool mordanted with hi- chroTnate of potash and dyed in a separate bath with Young Fustic, gives a reddish brown. The colour is much redder than that obtained in a similar manner from any other of the yellow dyewoods, with the exception of Persian Berries. Very large amounts of bichromate of potash may be used, and with good effect, but it is not advisable to employ more than 3 per cent. The addition of sulphuric acid is not beneficial. With an aluminium mordant it produces a yellowish buff colour. The brightest yellows yielded by Young Fustic are those obtained when it is used in conjunction with stannous mordants. With stannous chloride (or nitrate of tin) and tartar, and with a good quality of Young Fustic, bright orange yellows are obtained, not unlike those given by Quercitron Bark or Flavin. The same methods of dyeing and proportions of mordants employed in the case of Flavin may be adopted here, using only larger amounts of dyewood, say 20 — 40 per cent, of Young Fustic. With a stannic salt as mordant it yields a tolerably good full orange yellow, but only when prohibitory amounts of tartar are employed. The colours yielded by the use of cojjper and iron mordants are olives similar to those obtained from the other yellow dyewoods. The yellows and oranges obtained from Young Fustic are not fast to light, two or three months' exposure being sufiicient to bleach the colour entirely. All except the aluminium colour withstand milling with soap and weak alkalis moderately well. In these I'espects Young Fustic is not so good as any of the other natural yellow colouring matters. 366 DYEING OF TEXTILE FABRICS. [Chap. XY. PERSIAN BERRIES. 304. This colouring matter consists of the dried un- ripe fruit of various species of Rhainnvus; it is not used in cotton- and rarely in silk-djeing, although very largely in calico-printing for steam-orange, olive, green, — 60' C. in a bath containing a small quantity of soap, or " boiled-off "' liquor. Sc'metimes a little sulphuric acid is added to the bath. Wash well, bi-ighten in a cold bath very slightly acidulated with acetic acid, and dry. For yellow shades of gi-een, add to the dye-bath Auramine or other basic vellow colourLnoj matter. If Picric Acid or other acid colour is used, it must be added to the brightening bath, taking care not to use any excess of acetic acid, otherwise the green will be stripped off It is better to dry the silk at once after brightening, in order not to remove any Picric Acid by rinsing. Chap. XYI.] ROSAXILIXE COLOURS 375 ^ 314. Acid Green. — Several acid greens are met with m commerce, bearing such names as Helvetia Green (Soc Cham. Ind., Basle), Acid Green (Poirrier), Light Green S (BASF), Giimea Green (Act. GeselL, Berlin), &c. They are sodmm or calcium salts of the sulphonic acids of the base of one or other of the Benzaldehyde Greens. As their name impHes, they requii-e to be applied in an acid bath. Their dyeing power is less than that of the Benzaldehyde Greens, but employed with other acid colours they are extremely useful for producing compound shades. They are not suitable for dyeing cotton. Application to TToo?.— Dye with the necessary amount ^T.oo'i'''''' l^^ ^— ^ *^^^^ its weight of sulphuric acid Ibb Tw. (Sp. Gr. 1-84) added. An addition of 10—20 per cent, of sodium sulphate may also be made if there is any tendency to uneven dyeing. Raise the temperature gradually, to near the boiling point. Ap2)Iicatio7i to Silk— Bye at a temperature of 50^ with the addition of "boiled-off " liquor slightly acidified with sulphuric acid. 315. Alkali Green, Viri din. — This colouring matter, derived from diphenylamine by the Malachite Green process, or prepared by oxidising benzyl-diphenyl- amme with chloranil, is only of limited use. Bein- a sodium sulphonate of the colour-base, its dyeinc^ proper- ties are simQar to those of Alkali Blue, and it is applied m exactly the same way (see p. 379). Pleasing greenish shades of blue may be obtained on wool by using mixtures of Alkah Blue and Alkali Green. 316. Magenta. o\^^^^ This colouring matter, sometimes called Roseine, Ponceau, i.ubme, (fcc, IS usually the hydrochloride or the acetate of the organic base tolyl - diphenyl - triamido - carbinol or rosanihne. Various bye-products, containing impure Magenta, are sold under difi'erent names, e.g., Cerise 370 DYEING OF TEXTILE FABRICS. [Char. XVI. Grenadine, Cardinal, Amarantli, ! DYEING OP TEXTILE FABRICS. [Chap. XVL oleate of alumina. Work the bleached cotton in a hot (60° C.) soap bath (60 — 100 gi^ams of soap per kilo, of cotton), squeeze and -work in a cold bath of aluminium acetate, S^Tw. (Sp. Gr. 1'04), and squeeze. Repeat these operations three times, and dye in a fresh bath. One may also work the soaped cotton at once in a dye- bath to which aluminium acetate has l^een added. Add the colour solution in small portions, and heat gi*adually to the boiling point. Wash well in cold water, and pass finally through a weak soap bath heated to 60° C, to which a little acetic acid has been added till it just begins to show signs of turbidity. Cotton may also be prepared with tannic acid, and dyed in a fi^esh bath containing colour-solution and acidified with alum. Application to Wool — Dye with 1 — 5 per cent of colouring matter (or more if necessary), with the addition of 4—8 per cent, of sulphuric acid, 168"Tw. (Sp. Gr. 1-84), and 10 — 20 per cent, of sodium sulphate. Enter the wool at 50"— 60° C., heat up rapidly to 100^ C, and boil half an hour, or lonsrer if necessary. The acid and also the colour solution should be added gradually to the bath, and in small portions at a time, in order to ensure a regular colour. Instead of sulphuric acid one may also acidify with 10 — 12 per c^nt. of alum. When the red shades of blue are used, the addition of sulphuric acid gives the best colour; with the purer blues brighter shades are obtaiued with the iLse of alum. , Owing to their insolubihty, Spiiit Blues are very apt to dye unevenly, but they are pi*efeiTed by yam-dyers when the goods have subsequently to )ye milled- AppJicafio7i to SilJc. — Introduce the silk into a tepid bath containing "boiled-ofi" liquor" acidified with sulphuric acid. Add the colour solution by degrees, heat gradually to 100° C, and dye at this tempei-atm^. Wash in cold water and brighten with dilate sulphuric acid. 319. II. Soluble Blues.— The Soluble Blues o:enei^nv Cbap. XVI.] RORANILTNE COLOURS. 379 consist of the ammonium or sodium salts of the di- and ^r^-sulphonic acids of Eosaniline or Diphenylamine Blues. They vary considerably in purity of colour, and are marked R, B, 2 B, 6 B, &c. The redder shades are known by such commercial names as Serge Blue, Kavy Blue, Blackley Blue, &c., while those of purer tone are known as China Blue, Night Blue, Soluble Blue, Water Blue, Cotton Blue, ka. Application to Cotton. — The cotton is prepared with tannic acid and tartar emetic, and dyed at 60° — 70° C, in a separate bath, slightly acidulated with alum. Light shades of blue are frequently dyed without any previous preparation. The method given for Spiiit Blue may also be used. Another method recommended is to work the cotton at 60° C. in a bath containing the colour solution and 3 per cent, of stannate of soda. When the cotton is properly saturated, acidify the solution with sulphuric acid, and work ^ hour longer. In all cases the dye-bath should be preserved, since not only is the bath never completely exhausted, but further lots dyed in the same bath have also a brighter colour. Application to Wool. — Dye as in the same manner as with Spirit Blues. Application to Silk. — Dye as with Spirit Blues. 320. Alkali Blue. — This is a special kind of Soluble Blue; it consists essentially of the sodium salt of the 97io?zo-sulphonic acid of Bosaniline Blue. Both red and blue shades are met with ; they are marked accordingly with R, B, &c., or they have such names as Guernsey Blue, Fast Blue, Nicholson's Blue, &c. The red shades are faster than the blue shades, both to light and to the action of dilute alkalis in milling, &c. Alkali Blues are not applicable in cotton-dyeing. Applicatio7i to Wool. — Wool must always be dyed with Alkali Blue in a slightly alkaline bath (hence the name). The wool takes it up in the form of a colourless sodium 380 DYEING OF TEXTILE FABRICS. [Chap. XVI. salt. The development of the colour, i.e., the precipita- tion on the fibre of the blue-coloured mono-sulphonic acid, is effected in a separate and slightly acid bath. The water of the dye-bath should be as free from lime-salts as possible, since the lime compound of the mono-sul- phonic acid is insoluble. In dyeing wool, add to the dye-bath the amount of colour solution requisite to obtain the desired shade (say 0'5 — 5 per cent.), and dissolve in it also 4 — 8 per cent. of carbonate of soda (crystals). Introduce the wool into the bath at 40° C, heat rapidly to 80° or 100° C, and boil h — J hour. It is then taken out, washed well in water, and transferred to a bath containing water slightly acidulated with sulphuric acid (5 per cent, of sulphuric acid, 168'^ Tw.). It is worked in this bath for 15 — 20 minutes at 60'' 0., until the colour is fully de- veloped, and is then washed free from acid. If the first bath, or the dye-bath as it may be called, is sufii- ciently alkaline, the wool acquires therein only a very pale bluish tint, but on passing it into the second bath, which may be named the acid or developing bath, the blue is at once developed. The dye-bath is never exhausted, and should always be preserved. For succeeding lots of wool add proportionately less of both colour solution and carbonate of soda. Instead of carbonate of soda, borax or strong ammonia solution may be used. Under no circumstances whatever should the sulphuric acid be added to the dye-bath, otherwise the colour-acid will be precipitated. In order to preserve uniformity of dye in several lots of material, it is very advisable not to develop different shades of blue in the same acid-bath. The acid-bath should never be employed at a temperature above 80° C, otherwise the blue is less brilliant. In order to match-off any given shade, a small sample of the woollen material must occasionally be taken from the bulk during the dyeing operation, and passed through warm dilute acid to develop the blue. Only in this way is it possible to regulate what amount of colour solution Chap. XVI.] ROSANILINE COLOURS. 381 should be added to the dye-bath, and to determine the duration of the dyeing operation. Many Alkali Blues are not improved in colouring power by an addition of carbonate of soda to the dye- bath ; they seem to be already sufficiently alkaline, while others give even inferior colours if the addition is made. In all cases a large excess of alkaline salt is to be avoided, since it tends to impoverish the colour. Colours said to be somewhat faster to milling are ob- tained by adding zinc sulphate or alum to the acid-bath, since these salts form insoluble lakes with the colouring matter. Alkali Blue may be employed for the purpose of obtaining compound colours, by using it in conjunction with various acid-colours, e.g., Crocein Scarlet or Orange, &c. In these cases the acid bath is dispensed with, and after dyeing with Alkali Blue and washing, the wool is at once worked in the dye-bath of the acid-colour, with the necessary additions. The development of the blue, and the dyeing of the scarlet, orange, &c., thus take place simultaneously. Application to Silk. — Silk is dyed like wool, but it is preferable to use borax in the dye-bath instead of carbonate of soda or ammonia. C C6H,-NH(CeH,) 321. Rosaniline Violets. C ] c'I^chJ^'^'^ These violets, also called by such names as Phenyl Violet, Spirit Violet, Parma Violet, Imperial Violet, (fcc, are liydrochlorides of mono- and di-phenyl-rosaniline. They find now only a limited use, being less bright than the Methyl Violets ; they are, however, said to be somewhat faster to light and to milling, and may be used with advantage when a dull, moderately fast violet is required, e.g., in felt-hat dyeing. Closely related to Rosaniline Violet is the so-called Regina Purple (Brook, Simpson, and Spiller). 382 DYEIXG OP TEXTILE FABRICS. LChap. XVI. Application to Cotton. — Pi-epai-e the cotton with tannic acid and tartar emetic, and dye in a bath slightly acidulated with stdphnric acid or aluni. Application to Wool. — Dye at 60° — 80° C. in a colour solution acidulated with -i per cent, of sulphuric acid, 168' Tw. (5p. Gr. 1-81). Since these are basic colouring matters, the need of acidulating the bath is noteworthy. Application to Silk.—Dje\t 60°— 80= C. in a bath containing boiled-off liquor, slightly acidulated with sxd- phuric acid. aH/XHCH^ 322. Hofmann-s Violet. C • c'h -CH ^^' f XHCH.a This colouring matter, also called Dahlia, Primula, «fcc, is considered as the hydrochloride of the base trimethyl- rosaniline : it is only used for red shades of violet, the bluish violets beincr better obtained from the Methvl Violets. The colour it yields is not fast to light. Application to Cotton. — Prepare the cotton with tannic acid and tartar emetic, or \nxh. sulphated oil and alu- minium acetate; wash and dye at -1:5° — 50° C. in a neutral bath. Application to Wool— Dye at 60° — 80° C. in a neutral bath, or with the addition of 2 — 4 per cent of soap. Application to Silk. — Dye at 50' — 60' C. in a bath con- taining soap or "boiled-off'" liquor, with or without the addition of a little sulphuric acid. Wash and brighten in a bath slightly acidulated with acetic or tartaric acid. 323. Methyl Violet. C ] l^'^ >^'^^'« ( XH-CHs-a This colouring matter, also called Paris Violet, is con- sidered as the hydi'ochloride of penta-methyl-para-ros- aniline. "Various brands are sold — e.g., Methyl Violet R, B, 3 B, «tc. — according as they yield red or blue shades of violet. Some of the Methvl Violets are zinc double salts, and Chap. XVI.] ROSANILINE COLOURS. 383 are then sold in the crystalline state; with these the addition of soap to the dye-bath raust be strictly avoided The methods of applying them to the textile fibres are identical with those employed for Hofmann's Violet. 324. Benzylrosaniline Violet. — This colouring matter is the benzyl (O^H-) derivative of Methyl Violet. The most highly benzylated product is generally sold as Methyl Violet 6B, and by mixing this in different proportions with Methyl Violet B, the various marks of Methyl Violet 2B, 3B, 4B, 5B are obtained. Benzyl Violet yields much bluer shades of violet than Methyl Violet, although the method of its application to the various fibres is very similar. It bears the addition of a little sulphuric acid to the dye-bath better than Methyl Violet. Alkali Violet (Meister, Lucius, & Briining) is applied in the same manner as Alkali Blue. ( CQHo^CH3}-XH(CH3)S03Xa 325. Acid Violet 4 RS. ^ ) CgH^-XHlCHsjSOaXa (BASF). ^ ) CgHgSOsNa This colouring matter is the sodium salt of di-methyl- rosaniline-tri-sul phonic acid. Acid Violet 5 RS (basf) is the corresponding mono- methyl compound. Acid Violet 6 B (basf) is the corresponding benzyl- methyl compound. These colouring matters, sold by several manufac- turers with different brands, are adapted only for wool and silk, and are applied in the same manner as Acid Magenta. They are useful, in conjunction with other acid colouring matters, for producing compound shades. ( QH,-X(CH3)o 326. Methyl Green, c ] g^g^"^ ^^^^^-^'^^^'Cl ( XH-CH3-C1 This colouring matter may be regarded as the methyl chloride compound of Methyl Violet. It occurs in commerce in the crystalline state as a zinc double salt. 384 DYEING OF TEXTILE FABRICS. [Chap. XVI. Although still used, it has been very largely supplanted by the Acid and Benzaldehyde Greens, since these are much cheaper, and offer certain advantages in point of application and stability. Application to Cotton. — Dye in the same manner as with Benzaldehyde Green. Application to Wool. — Owing to the weak attraction which wool has for Methyl Green, it is necessary that it should be mordanted previous to being dyed with tliis colouring matter. The ordinaiy mordants, however, are of no use, and recourse is had to the singular and strong affinity which amorphous sulphur has for Methyl Green. The wool is mordanted in a bath containing 10 — 20 per cent, of thiosulphate of soda (usually called hyposul- phite of soda) and acidified with 5 — 10 per cent, of sul- phuiic acid, 168^ Tw. (Sp. Gr. 1"84), or hydrochloric acid, 32^ Tw. (Sp. Gr. M6). Introduce the wool into the milky liquid at 40^ C, raise the temperature gi'adually to S0° C. in the course of an hour, then wash well. Dye at 50° — 60° C. in a separate bath containing Methyl Green and 2 — 4 per cent, of borax or acetate of soda. The addition of these latter salts to the dye-bath has the effect of neutralising the acid remaining in the wool after washing : if, however, previous to dyeing, the wool is worked for about a quarter of an hour at 70° C. in a weak solution of carbonate of soda or ammonia, their ad- dition to the dye-bath is unnecessaiy. The shade produced by Methyl Green is always bluish, and if the temperature of the dye-bath is liaised to 100° C. it becomes still bluer, owing to a portion of the colouring matter decomposing at this temperature with elimination of methyl chloride and the production of Methyl Violet ; the effect obtaiaed is that of a mixture of green and violet, namely, blue (Peacock blue). If it is desired to obtain j'^el- lower shades of green, Picric Acid may be added to the dye- bath, but since this only dyes in an acid-bath (a condition which is prejudicial to the dyeing property of Methyl Green) one must add also a small proportion of acetate of Chap. XVI] ROSANILINE COLOURS. 385 zinc. This salt is gradually decomposed by the suljDliur already fixed on the wool, and the liberated acetic acid causes the Picric Acid to dye, while it does not prevent the Methyl Green from doing so. The zinc sulphide pro- duced, acts as a mordant for the Methyl Green in the same manner as the sulphur. Should, however, the Methyl Green dye slowly, from over- acidity of the bath, the addition of a little acetate of soda is necessary. It is essential that in the operations of mordanting and dyeing, the use of metal, either in the dye-vessels tliemselves or in the utensils employed, should be strictly avoided, otherwise the wool may acquire a dark colour, or be spotted, by the production of metallic sul- phides. Application to Silk. — Dye exactly as in the case of Benzaldehyde Green. 327. Auramine (basf) (Soc of Chem. Ind., Basle). [C6H^X(CH3)2]2 -C-^^H-HCl.— This yellow colouring matter is the hydrochloride of tetra-methyl-diamido- benzo-phenon-imide. It is particularly useful to the cotton-dyer, and is said to resist the action of light and soap solutions fairly well, but is readily affected by chlorine. It should be dissolved in hot water, but the solution should not be boiled, since the colouring matter is thereby decomposed. It is useful for producing com- pound shades in conjunction with other basic colouring matters, e.g., Safranine, Benzaldehyde Green, etc. Application to Cotton. — Mordant the cotton with tannic acid and tartar emetic, and dye in a separate bath. Introduce the cotton into the cold colour solution, and raise the temperature of the bath to 40^ — 50^ C. Application to Wool. — Dye in a neutral bath. Enter cold and heat gradually to 70"^ C. Better colours are said to be obtained if the wool is previously mordanted with sulphur, after the manner in vogue for Methyl Green. AptjMcation to Silk. — Dye in the same manner as with Magenta. 3S6 DYEING OF TEXTILE FABRICS. TChap. XVI. rC,H,X'C,H5), 328. Ethyl Purple 6 B (basf). c] cJhI^'^"^'^ This colonring matter is the hydrochloride of hexa-ethyl- para-rosaniline. It is the bluest shade of violet at present known, and is applied to the various fibres in the same wav as Hofmann's Violet. C C,H,X'CH3), 329. Crystal Violet 5 BO (basf). C ] ^§^^ ^^'- This colouring matter is the hvdrochloride of hexar methyl-para-rosaniline. It is applied to various fibres like Hofmann's Violet, over which it possesses the advantage of gi-eater colouring power, of extreme solubility in water, and of having no tendency to produce a bronze scum on the surface of the dye liquor or on the dyed material 330. Victoria Blue 4 R q) cI^A^-s'^crI C^K^) (BASF). i ^^^4 This colouring matter is the hydrochloride of penta- methyl-phenyl-triamido-diphenyl-a-naphthyl-carbinol. It is applied to the various fibres in the same manner as Hofmann's Violet. TVool and silk may be dyed with the addition of a little acetic or sulphuric acid to the bath, in the same manner as acid colours. The dyeing power is thereby somewhat lessened and the bath is not so well exhausted, but the colour obtained seems brighter. 331. Victoria Blue B (basf). C ) CaA-XH-iC^H^ ( X',CH3)2 CI This is the tetra-methyl compound corresponding to Victoria Blue 4 R, and may be applied in the same way. 332. Night Blue (basf). This colouring matter is closely related to the last, and is applied to the textile fibres in a similar manner. It requires to be dissolved in dilate acetic acid to prevent decomposition on boiling. Chap. XVI.] INDULINE COLOURS. 387 333. Phosphine [C^^Hi^Ng-HCl].— This orange colour- ing matter (said to be a quinoline derivative) is the hydrochloride of the base chrysaniline. Its dyeing properties are similar to those of Magenta, and it is applied to the textile fibres in the same manner. It finds only a limited use in wool- and silk-dyeing because of its expense. 334. Rosolane [Co:H2,N9-HCl].— This colouring mat- ter is the hydrochloride of the base mauveme ; it is, indeed, the original Perkin's Violet. It is sold at the present time in the form of a paste. Its method of application is similar to that of the Methyl Violets. Although itself not requiring a mordant, it may be used in conjunction with polygenetic colouring matters for the production of compound shades. It is used as a substitute for Orchil or Ammoniacal Cochi- neal in the production of bright greys. h. Induline and Safranine Group. 335. Indulines. — These comprise a number of colour- ing matters made by difierent processes, but all possessing somewhat similar dyeing properties. They are known by a variety of commercial names, e.g., Violaniline, Xigro- sine, Elberfeld Blue, Bengaline, Aniline Grey, Coupler's Blue, Roubaix Blue, itc. Those used for cotton-dyeing are insolub]e in water, and require to be dissolved in methylated spii'it. These Spirit Indulines are hydrochlorides of a colour-base, e.g., violaniline, triphenyl-violaniline, kc. For wool- and silk- dyeing they are treated with strong sulphuric acid ; they are thus rendered soluble in water, and are sold as sodium salts of the corresponding sulphonic acids. They all yield dark dull blue colours, not unlike indigo-vat blues, to imitate which, they are frequently employed. Apjyhcaiion to Cotton. — Prepare the cotton with tannic acid and tartar emetic, vrash, and dye in a separate bath containing the colour solution, acidified slightly with 388 DYEING OF TEXTILE FABRICS. [Cliap. XVI. sulphuric acid or by the addition of alum (10 per cent.). Dye at a temperature of about 60'^ C. The bath is not exhausted, and must be preserved for succeeding lots of material. One may also employ the indigo-vat method. Applicatwn to Wool. — Owing to the precipitation of the free sulphonic acids of these colours on the addition of acid to their solutions, it is extremely difficult to dye liglit shades evenly with them. They are best adapted for dyeing dark shades. Add the requisite amount of colour-solution (5 — 15 per cent) to the dye-bath, heat to 100° C. as rapidly as possible, enter the wool, and boil 1 — 1^ hour, without any other addition. Continue now to boil one hour longer, during which period add from time to time dilute sul- phuric acid in small portions. Use 5 — 15 per cent, of sulphuric acid, 168'^ Tw. (Sp. Gr. 1"84;, according to the amount of colouring matter employed. The long boiling with colour solution alone, enables the wool to become thoroughly permeated with the colouring matter while still in the soluble state. An addition of 5 — 10 per cent, of borax, carbonate of soda, or strong ammonia solution at tliis stage is beneficial The actual dyeing of the wool begins only when the bath is acidulated ; the addition of acid should always be made slowly, so that the wool may take up the gradually precipitated colouring matter as evenly as possible. Wool is said to dye much better with Induline if it has been previously rinsed in a weak solution of bleach- ing-powder and then in dilute hydrochloric acid. These colours have been fi'equently recommended as good substitutes for indigo- vat blues. Although fairly fast to light, they gradually lose their bluish tint and brilliancy on exposure, and assume a dull greyish tone. Towards weak alkalis they are modei'^tely fast ; the action of acids they withstand perfectly In conjunction with other acid-colours they are useful for producing a large variety of compound shades. Application to Silk. — Dye in a bath containing Chap. XVI.] SAFRAXINE COLOURS. 389 " boiled-oflP" liquor, acidified slightly with sulphuric acid. Enter the silk at 60^ C, add the colour solution gradually, raise the temperature gradually to 100° C, and boil half an hour. Wash and brighten with dilute sulphuric acid. 336. Naphthalene Pink [C^jHsiXg-HCl + H.O]. — This colouring matter, also called Magdala Red, and derived from amido-azo-naphthalene, is the hydrochloride of the base rosa-naphthylamine. It is but little used, namely, for the purpose of obtaining on silk bright pinks, which have a strong yellowish-red fluorescence. Afjplication to Silk — Dye in a bath containing " boiled- off " liquor, with or without the addition of sulphuric acid. Brighten with dilute sulphuric or tartaric acid. The colour is faster than that given by Magenta, Eosin, or Saf ranine ; it is fast to dilute acids and alkalis, but not to light. 337. Safranine [CoiH22N4-HCl]. — In chemical consti- tution this red colouring matter is apparently allied to Magenta, and is the hydrochloride of a colour-base safra- nine. It is applied to the various fibres in the same manner as Magenta. On wool the colour is not fast to light. Strictly speaking, the name Safranine is given to several closely-allied products. Fuchsia (Soc. Ch. Ind., Basle) is dimethyl-aniline-saf ranine. Application to Cotton. — Prepare the cotton with tannic acid and tartar emetic, wash and dye in a neutral bath at 50^ C. One may also steep the cotton in a solution of lead acetate (with or without previous impregnation with a solution of soap), dry, and dye in a neutral bath of the colouring matter ; the colour thus obtained is objectionable because of the lead it contains. Fixed with tannic acid and tartar emetic the colour is fairly fast to light. Application to Wool and Silk. — Dye in the same manner as with Magenta. Neutral Red — (L. Cassella & Co.). — Tliis colouring matter and others called Neutral Blue and Neutral Violet being allied to Safranine, are all applied to the various 390 DYEING OF TEXTILE FABRICS. [Chap. XVI. textile fibres by similai' metLods. They yield dull shades of red, blue, and violet respectively, not fast to light on wool. They are of little use in -wool- and silk-dyeing, but may be used with advantage by the cotton-dyer for producing compound shades. New Blue D (L. Cassella s j^lC6H3-N(CH3)2-Cl Methylene Blue, a derivative of dimethyl-aniline, is sold Chap. XVlI.l QUINOLINE COLOURS. 397 as a zinc double salt in the form of powder. It is princi- pally used in cotton-dyeing, and gives a greenish blue, much valued on account of its great fastness to soap and also, it is said, to light. For silk- and wool-dyeing it has less importance ; since on these fibres it is not fast to light nor is it so bright as other blues. Application to Cotton. — The cotton is prepared with tannic acid and tartar emetic, then washed and dyed in a separate bath containing Methylene Blue solution. The addition to the dye-bath of a small quantity of carbonate of soda or ammonia is beneficial. Enter the cotton cold, and raise the temperature gradually to 100'"^ C. For dark indigo-blue shades the tartar emetic may be substituted by nitrate of iron. Application to Wool. — Add to the dye-bath the requisite amount of colour in solution (0*5 — 5 per cent.) and 1 — 2 per cent, of carbonate of soda (crystals) or ammonia. Enter the wool cold, and raise the temperature gradually to 100° C. in the course of half an hour, and boil half an hour longer. The dye-bath cannot be exhausted. Excess of sodium carbonate is injurious. Ethylene Blue. — This colouring matter is applied like Methylene Blue, and has similar properties. It is prepared from diethyl-aniline. CHAPTER XYII. QUINOLINE COLOURING MATTERS. 345. Plavaniline (Meister, Lucius, and Briining) [C,H5N(CH3)-CeH,(NH2)-HCl]. This basic yellow colouring matter, derived from acetanHide, is the hydrochloride of the quinoline base flavaniline. It is applied to cotton, wool, and silk, in the same manner as Magenta. On wool the colour is 398 DYEING OF TEXTILE FABRICS. [Chap. XVIII. developed a little by passing the dyed material through dilute sulphuric acid. Brighter coloure are obtained on wool mordanted with thiosulphate of soda according to the method employed when dyeing with Methyl Green, riavaniline yellow is not fast to light. Flavaniline S is an alkali salt of the sulphonic acid of the flavaniline base. It is applied to wool and silk in an acid bath. Quinoline Blue [C^^gHo^NoI]. — This disused colour- ing matter, also called Cyanine, is applied to cotton, wool, and silk in the same manner as Magenta. The colours it yields are very fucritive towards light. Quinoline Yellow (Act. Gesell. Farben Fabrik, Berlin). — This colouring matter is the sodium salt of the sul- phonic acid of quinoline - phthalein. It gives a pure yellow colour, and is applied in an acid dye-bath in the same manner as other sulphonic acid colouiing matters. CHAPTER XYIIL PHENOL COLOURING MATTERS. (a) Nitro Compounds. 346. Picric Acid [CeHo(X0,)3-0H].— This colouring matter is tri-nitro-phenol ; it is used only in silk- and wool-dyeing. Cotton has no attraction for it, and although it may be fixed on this fibre by means of albumen, the method has no practical value. The animal fibres, on the contrary, readily take np Picric Acid from an acid solution. It gives a clear bright vellow, free from anv tinee of orange ; indeed, when compared with most other yellows it appears to have a greenish hue. Application to Wool. — Dve for h — 1 hour at 60°— 100^ C. with 1—4 per cent, of Picric Acid, with the addition of 2 — 4 per cent, of sulphuric acid, 168° Tw. Chap. XVII I] PHEXOL COLOURS. 399 (Sp. Gr. 1-84). The bath must be preserved, since it cannot be exhausted. By repeated washing with water only, it is possible to remove nearly the whole of the colour from the dyed fibre. It does not stand milling well, both on this ac- count and because the colour becomes brownish under the influence of alkalis. It is also not a good dye for the woollen part of mixed goods (wool and cotton), since it comes off in the tannin bath used for preparing the cotton. It is fre- quently employed for the production of compound colours, e.g., with Methyl Green and with Indigo Carmine for yellowish greens, with Acid Violet for olive, tC6H4CO-0 I I This fine purple colouiing matter, sometimes called Anthracene A^iolet, is derived from phthalic anhydride and pyrogallol. It is sold in the form of a reddish- brown powder or a 10 per cent, paste, not very soluble in cold water, but readily so in hot. It ought to be much more used than it is, since it gives fine purple shades on cotton, wool, and silk, which are tolerably fast both to light and soap. Cl,ap,XVin.] PHTnALEiN COLOURS. 407 alu,^ni^t^"'T '".C-otto^.- Prepare the cotton with mannei, and dye in a separate bath with Gallein Tlie M^nZT" '" t"''"^^ ^'* *''^' "^'^d i" ^Vein's with A 1 '. ^°«"'7''' "'• "th^'- Polygenetic colouring matters, hv ttl ■"o'-dants yield purple colours, those obtained by the use of chromium and iron being bluish, those of to reddish, and tho.se of aluminium intermediat; in tone All the colours may be regarded as fast to light and scan cent ^f 1"?"" '" "^r'-^^-dant the wool with 2 pt cent of bichromate of fotmh. The addition of sulphuric duHsT" , '^' 'f^'"'*."^ 1 P^^ <=^-*- i^ i^^Jurious^ and dulls the colour. Dye in a separate bath with lO-on matter t?,fn'' ^^'^' ^?"*^i°'°g !« P^^ cent, of solid maduallvfn tV, . -7°°' '°'^' ""^^ '^''' '^^ temperature ^ladually to the boihng point. The shade thus produced IS bluish-purple or violet. I'louucea With alummiimi mordant a much redder and bric^hter purple IS given. Mordant with 6-8 per cent of afnnT With thf tv°' ?T' P^^ «^"*- °'"e-of tart": wihte, t' V,1'°™TV' ""^-^^ intense and .slightly b.ightei. Ihe addition of chalk to the dve-bath is not to I'Sr^r'^^V-T" ^"^"^ ' P^'- ''^'- '^^ colour ^muc*^ deteriorated, -ftith iron mordants Gallein gives a deen ::f t:::"" T^" ' 'T^^-^'i'- ^''^^^ -'p'-^ -^5 An f V, «">glebath method is also applicable. AH the above Gallein colours are speciallv ad»r,te^ for goods^ which have to be milled. Thf clronfiumT„r dant IS the most generally useful of those mention d 6za IS dyed in the same way as with Alizarin (p. 456). 364. Coerulein CeHj ^°°^^lo~° T,,. , (COC^HfoiD-O ihis green colouring matter, also called Anthracene ^cid'aV'' r"w *™" *^^"^^'^ ^y "^^ action o7 sulphuric acid at a high temperature. It is sold in tw^ f„ either as a thick bla'ck paste (C»r^\m paste)*c7ntl°3^ 408 DYEING OF TEXTILE FABRICS. [Chap. XTIH. 10 — 20 per cent, of Coerulein, or as a black powder. The former is more or less insoluble in water, and re- quires in some cases the addition of bisulphite of soda to render it soluble. The latter, kno^vn as Coerulein S, is soluble in water, and is indeed a compound of Coerulein with bisulphite of soda [C^^HgOg'iXaHSOg] ; this form is the one most easily applied. At the present time Coerule"in is mostly employed in calico-printing for producing very fast olive- green shades. The colours it yields both on cotton and on wool are re- markable for their fastness to light, acids, alkalis, ttc, and whenever its price permits, it will find an extensive use in the dyeing of these materials. Whatever the mordant used, only different shades of olive-green are ob- tained. The use of copper dye-vessels should be avoided. Applicatioji to Cotton. — If insoluhh Coerulein is heated with a mixture of caustic alkali (XH3) and zinc powder, a brownish-red solution of the reduction product Coeridi7i is obtained, which on exposure to air imme- diately becomes green again, with precipitation of the original Coerulein. This brownish-red liquid or " Coeru- lein- vat " as it might be termed, may be used for dyeing after the manner of the indigo- vat. If the solubU Coerulein S is employed, the cotton must be previously prepared with aluminium, chromium, iron, or tin mordant, according to the usual methods, and then dyed in a simple solution of the colouring matter. Care should be taken to begin dyeing at a low temper- ature, and to raise it very gradually to 100^ C. During the dyeing process sulphurous acid is given off, and the liquid becomes green and alkaline. The water employed should be free from salts of lime and other alkaline earths, since these produce insoluble lakes with Coei'ulein. The insoluble form of Coerulein may be applied in the same way, if bisulphite of soda is added to the bath to render it soluble, but the results are not quite so satisfactory. Applicatioji to Wool. — On wool the most generally useful mordant is bichromate of pot-ash. Chap. XVIII.] PHTHALEIN COLOURS. 409 Mordant the wool with 2 — 3 per cent, bichromate of potash and — 0*7 per cent, sulphuric acid, 168*^ Tw. (Sp. Gr. 1-84). "Without sulphuric acid the colour is slightly paler. Dye in a separate bath containing only Coerulein S. Enter the wool cold, and raise the temper- ature very gradually (say in the course of half an hour) to 60° C. Dye at this temperature for about one hour, then heat gradually in the course of half an hour to 100° C, and boil for a quarter of an hour. The addition to the dye-bath, during the last quarter of an hour, of 1 — 2 per cent, of chalk, makes the shade bluer, but generally speaking the addition of chalk or calcium acetate to the bath is to be avoided. With 2 per cent, of Coerulein S a pale sage- green is obtained, with 5 per cent, a medium olive-green, and with 10 per cent, a very dark green, almost black. These colours may be used instead of indigo-greens, being equally fast to light, milling, &c. With aluminium mordant shades can be obtained which are somewhat bluer or greyer than with bichro- mate of potash, but they are very apt to be uneven. With iron mordant dirty olive and olive-black shades are obtained. Use 4 per cent, of ferrous sulphate and 8 ])er cent, of cream of tartar, and dye with 0*5 — 10 per cent, of Coerulein S. If wool is mordanted with an amount of pure stannic chloride equivalent to 5 per cent. SnClg'SHgO (tin-crystals), it needs the addition of 40 per cent, of cream of tartar to yield a normal bluish -green colour, when dyed afterwards with 5 per cent, of Coerulein S ; but it is remarkable that even without the addition of any tartar a full greyish- black colour is obtained. (With the majority of poly- genetic colouring matters, stannic chloride is an unsatis- factory mordant.) With 5 per cent, of Coerulein S, the colour is perhaps too much like a bad black to be of general use, but with 0*5 — 2 per cent, very pleasing greys are obtained. Another method of dyeing with Coerulein is to boil the wool with its sodium carbonate solution for some 410 DYEING OF TEXTILE FABRICS. [Chap. XVin. time, and then gradually to acidify with sulphuric acid in order to precipitate the colouring matter within and upon the fibre, but it only yields a dull colour. By mordanting wool with bichromate of potash and dyeing with mixtures of Coerulein S and Alizarin or Anthrapurpurin, a great vaiiety of fast browns and olives are obtained. Coei'ulein S may of course be used in the same bath with all polygenetic colouring matters. Application to Silk. — Coerulein has scarcely been introduced into silk-dyeing, though it is capable of giving good fast shades. Mordant in the usual manner with alum, dye in a separate bath with Coerulein S, and brighten with a solution of soap. (e) Indophejwls. 365. a-Naphthol Blue (L. Cassella & Co.). Dimethyl-amido-phenyl-ox^-naphthylamiiie. — This colouring matter, also called Indophenol Blue N, is produced by oxidising a mixture of dimethyl-^;-phenylene- diamine and a-naphthol, or by the action of nitroso- dimethyl-aniline on a-naphthol. It gives colours very similar to vat-indigo blues, and which are said to be moderately fast to light. They are, however, extremely sensitive to the action of acids ; even weak acids destroy the blue colour and change it to brown. Indophenol Blue N is better adapted for woollen- and calico-printing than for dyeing. Under the influence of reducing agents — e.g., glucose and caustic soda, stannous chloride and carbonate of soda, itc, — Indophenol Blue is changed into indophenol- white, which is soluble in pure or acidulated water. For the preparation of indophenol-white, mix to- gether 10 kilos, of Indophenol Blue (paste) and 60 litres of water ; add 30 litres of a 10 per cent, solution of tin ciystals (SnCl2"2H20), and heat to 25 '^C. until reduction takes place. Chap. XVIII.] IJJDOPHENOL COLOURS. 411 Application to Cotton. — Dye for ten minutes at 40° C. in a solution containing 5 — 10 grams, of indophenol-white per litre, then wring out and wash, and develop the colour by working the cotton for about two minutes at 50"^ C. in a dilute solution of bichromate of potash. Better colours are obtained if the cotton is previously prepared with sulphated oil. Application to Wool. — Dye for fifteen minutes at 80° C. in a solution of indophenol-white, rendered either alkaline by the addition of sodium carbonate, or acid by means of acetic acid. Wring out, wash, and develop the colour by exposure to air, or by working the material for a few minutes in cold dilute solution of bichromate of potash, or an ammoniacal solution of sulphate of copper. For dark shades the solution of indophenol- white should be concentrated ; the dye-bath is not ex- hausted, and should always be preserved. 366. Gallocyanin (Durand and Huguenin). — This colouring matter, also called New Fast Yiolet, is obtained by the action of nitroso-dimethyl-aniline on tannic acid. In dyeing, it yields a bluish-violet colour possessing only moderate brilliancy, but tolerably fast to the action of acids, alkalis, and light. Applied in conjunc- tion with other colouring matters, it is useful for obtaining compound shades. Ajjplication to Cotton. — Mordant the cotton by means of an alkaline solution of chromium oxide, and wash well. Dye in a separate bath with Gallocyanin, at a tempera- ture of 80* C for 1 — li hour. If, after dyeing, the cotton is washed, dried, and steamed, the colour becomes some- what darker and faster. Applicatioji to Wool. — The wool may be dyed without any previous preparation, or it may be first mordanted in the usual manner with bichromate of potash. Dye in a neutral bath. Introduce the wool into a cold solution, raise the temperature gradually to 70° C. in the course of one hour, and continue dyeing for -g- — 1 hour longer. 412 DYEING OF TEXTILE FABRICS. [Chap. XIX. Application to Silk. — Dye at 70° — 80° C. in a bath containing colour solution and " boiled-ofif '' liquor. The silk may be previously mordanted with chrome alum, though this is not absolutely necessary. CHAPTER XIX. AZO COLOURING MATTERS. (a) Amido-azo-colours. 367. Aniline Yellow [CeHs-N^N-CeH^-NH^HCl]. Diainido-azo-benzene-h.ydrocliloride. — This colouring matter is no longer used in dyeing, because the colour which it yields is volatile and not fast. Cotton has no attraction for it. Wool and silk may be dyed in a bath slightly acidified with acetic acid. 368. Chrysoidine [C6H--N = NC6H3(NH2)2-HC1].— Diamido-azo-benzene-hydrochloride. This colouring matter, much used in cotton-dyeing for producing various shades of orange, is prepared by the action of diazo-benzene-chloride on m-phenylene-diamine. It is well adapted for shading, and may be used as the yellow part in a number of compound shades, e.g., olive, brown, scarlet, &c. Chrysoidine FF (L. Cassella &, Co.) is the corresponding toluene compound. Application to Cotton. — Mordant the cotton with tannic acid and tartar emetic, and wash ; dye at 60° C. in a solution of the colouring matter, without any further addition. Avoid high temperatures, since the colour is thereby rendered duller. Sometimes the fixing of the tannic acid with tartar emetic may be omitted, and for very light shades it is not even necessary to prepare the cotton with tannic acid, since this fibre seems to possess naturally a certain attraction for Chrysoidine. Good shades are Chap. XIX.] AMIDO-AZO COLOURS. 413 obtained by applying Chrysoidine to cotton previously dyed with Catechu, Sumach, &c. Application to Wool. — Dye at 60° — 70° C. in a neutral bath, or with the addition of 2 — 4 per cent, of soap, or one acidified with alum. These additions tend to brighten the colour. The addition of sulphuric acid to the dye- bath impoverishes the colour, but if, after dyeing accord- ing to the above method, the wool be worked for 10 — 15 minutes in cold water slightly acidified with sulphuric acid, the colour acquires a deeper and redder hue. Dyeing at 100° C. dulls the colour considerably. Application to Silk. — Dye at a temperature of 60° C, with or without the addition of a little soap to the dye-bath. Brighten in a bath very slightly acidified with sulphuric acid. 369. Phenylene Brown. — [C6H4-(NH2)-N = N-C6H3(NH2)2-2HC1] Triamido-azo-benzene-hydrochloride. This colouring matter is prepared by the action of nitrous acid on m-phenylene-diamine, and dissolving the base thus produced in hydrochloric acid. It also bears the commercial names : Bismarck Brown^ Vesuvine, Ca- nelle, Manchester Brown, Cinnamon Brown, &c. Bismarck Brown G G and E E (L. Cassella & Co.) are the pure products of toluylene-diamine and phenylene- diamine respectively. Application to Cotton. — Prepare the cotton with tannic acid and tartar emetic ; wash and dye in a neutral bath at 50° — 60° C. Add the colour solution gradually. A slight addition of alum to the dye-bath may sometimes be made to niodify the shade. The shades given by Bismarck Brown are similar to those obtained from Catechu, but, as a rule, brighter. Light shades can be dyed without previous preparation of the cotton. Catechu browns are frequently dyed with it in order to brighten or modify the colour. A great variety of compound colours are obtainable 414 DTEIXG OP TEXTILE FABRICS. [Chap. XTX. by Qsng it aloi^ with other basic colotirmg matters, e.g., Magraitia^ Malairhite Green, Methyl Violet, Methylene Blue, Jkc A^plieatiom, to WooL — Dye in a nentral bath. For a full shade, use 5 — 8 pa* cent, of eolonring matter. The additiMi of 8 — 10 per cent, of alum to the bath makes tlie diade redder. Enter the wool at 45° C, and heat gndoaUj to 100* C AppKeaiiom, to Silk. — Dye in a weak soap bath at 60* G, and Is^kten in a fresh bath slightly acidified with aeetie or tartaric acid. (6) AmidKHizosulphonic Acids. 37a Fa£t TeQow.— [(S03Xa)CA-X=N-C,H,rs'H2)] ATJiirln iiiioliiiiif iiK iiniliiim ji i iiliiliiiiiiilr Tins eoloTiring n- ' ^-'-- is also called Acid Yellow; it cannot be naed for dy-,., ; ::.on. It is well adapted for using alwigwith other acid colouring matters to obtain com- pound shades on wool or silk. Employed alone it cannot emnpete with some other yellows in brilliancy. The above compound is sometimes distinguished as Fast Ydlow G, while Fast Yellow R is giren to the corre- iipandins' toluene c(»npoiind. Apj: Wool. — Dye in an acid bath. For 0"5 — 3 pri i-riii.. C'f colouring matter add 2 — 6 per cent. of sulphuric acid, 168" Tw. (Sp. Gr. 1-84). Enter the wool at 40* C, and heat gradually to 100° C. in the course of J — ^1 hour, and boil for \ hour. If 5 — 10 per cent, of afann be nsed mstead of sulphuric acid, the shade given is weaker and las orange. AppHoaJHam, to Silk. — Dye at a temperature of CO" — 80^ C, in a batli containing ** boUed-off " liquor and acidified with sulphuric acid. 371. Ofmetliylaiiiline Oranga — ji PiiiMtflijil ■■■iln mio lMiinii'»iiiiiiiiii ji i iilj^iliiiiiiih.'. Chap. XTX."] AMIDO-AZO ACID COLOURS. 415 Other commercial names of this colouring matter are: Helianthin, Gold Orange, Orange III., and Tropseolin J), (fcc. Application to Cotton. — Work the cotton in cold stannate of soda solution, 5° Tw. (Sp. Gr. 1 -025), till thoroughly saturated, and wring out ; work for \ — ^ hour in a cold solution of alum (15 — 20 per cent.) and wring out ; dye in a concentrated solution of the colour- ing matter, with the addition of an equal percentage of alum. Enter cold, and heat gradually to 45' C, but not higher. Dry without previous washing. The colour is not fast to washing. Applicatio/i to Wool. — Dye exactly as with Fast Yellow. Somewhat bricrhter shades are obtained bv usino^ stannic chloride instead of sulphuric acid. With 2 per cent, of colouring matter a full reddish-orange is obtained. Ajjplication to Silk. — Dye exactly as with Fast Yellow, 372. Diphenylamine Orange — [(S0jK)CeH4-X = N-C6H,(X-H-C6H,)] p-Phenyl-amid.o-azo-betLzene-pota.5siuin-p-sulp]ionate. This colouring matter is also called Tropaeolin 00, Orange lY., Orange X, Yellow X, (fee. It is very sensitive to the action of an excess oi free acid, which causes it to dve a more orano^e colour. Laro:e excess of mineral acid causes its solution to become violet through liberation of the free colour acid. Closely allied to this colouring matter are the three foUowTJig : — 373. Metanil Yellow (basf).— [(S07N'a:C,H4-X = X-C6H4:X-H-C,H5)] p-Phenyl-amido-azo-benzene-sodiuni-m-sulplioiiate. This colouring matter is also called Tropeeolin G (L. Cassella & Co.). 374. Brilliant Yellow (basf).— [(SOsXaXgHs'CHa/X^XC.H.^X-H-QH^)] p-Phenyl-anudo-azo-toluene-sodiuia-p-sulphonate. 416 DYEING OF TEXTILE FABRICS. [Chap. XTY. 375. Azoflavin 2 (basf). — [(S03Na)C6H4-Xz:N-C6H4(N-H-C6H4(N02))]. p-Ifitro-phenyl-amido-azo-'benzeiie-soditim-p-stilph.oiiate. All these colouring matters are specially suitable for wool- and silk-dyeing, and give fine yellow or orange shades. They are applied in the same way as Fast Yellow and Dimethylaniline Orange. The colours on cotton are not fast to washing. If 10 per cent, of alum is added to the dye-bath instead of sulphuric acid, the colours on wool are rendered brighter. Indian Yellow (L. Cassella erLzeiie~s:'diinn-j>-siDLlf4«saBba. This colonring matter has now little importance, having been repla^^d by other similar but superitH- colouriog matters. 380. Eesorcinol Yellow.— E.esorciiiol-a2,i>1:teiL2.cJi6-sodi-ain-j>^nliih.oixa.te. This coloTiring matter is also called tbopasolin O, Tn>- paeoHn K, ChrysfecJin, Chijsoin (Poirrier). It gives an (Hange dye of cnij mod^ate brilliancy, and is chieflj used along with other acad-colonrs to produce iTiamifacturers : — Pa :h with a stdation of almn: :> which a sxuaii prc^pcNrtion. o€ stannous added. After dijmg and ageing €fx' I. ^ the doth f/3-imphthol-sodiuin-triExilplioiia.te. New Coccin (m. l. *fc b.) ; Fast Red D (basf). — These colouring matters are isomeric with the last. Brilliant Scarlet 4 R (L. Cassella rd and 4zth Operations : Second and third green liquors. — These are almost exact repetitions of the second operation, the liquor employed being made up separately and with the same proportions of the several ingredients as given above. The sole difference is that it is not necessary to let the prepared yarn lie in pile over- night ; instead of this, if it is not raining, it is suspended on tin rods, and exposed to the open air for about 2 — 4 hours previous to stoving. It is e\T.dent that, after stoving, the dry yarn is charged with sodium carbonate, and since it is very important that all the liquors should be maintained regu- larly at the same specific gravity, it is customary not to allow the liquor expressed during the wi'inging of the hanks to flow back into the " tramping " box, except in the case of the "first green liquor," but to collect it separately, and then, if necessary, to dilutes it with water before using again. The total amount of oil used is about thirty per cent, of the weight of yarn, but only a portion of this becomes fixed on the fibre. bth, 6th, 7th, aiid Sth Operations: Firsts second. 432 DYEING or TEXTILE FABP.ICS. [Chap. XX. third,, and fourth ichite liquors. — The solution here used is simply carbonate of soda, at 2° Tw. (Sp. Gr. 1 "01), but ofter working the yam in it a short time, it necessarily becomes an oil emulsion from the oil stripped off the cotton, apart from the fact that it is always mixed with the surplus and expressed liquor from the similar opera- tions with previous lots of yam. The yam is " tramped " in the liquor, wrung out. exposed in the open air, and dried in the stove, as in the previous operations. ^th Operation : Stf.epiiig. — Steep the yam during 20 — 24 hours in water heated to 55° C, wash well, and dry in the store at about 60" C. If the yarn contains much unmodified oil, a solution of carbonate of soda at J° Tw. (Sp. Gr. 1-0025) may be used; in this case a second steeping for two hours in tepid water is requisite before washing, ';jy.>s:>^;si^;$^^'^^^^^^'^»^^ 1 Fig. 91.— Oil-padding Machine. being well opened out and made free from creases before entering the oil, by means of the straining bars AAA, and afterwards loosely plaited down by the folder D. After padding, the cloth is detached in ten-piece lengths, and hung in the drying stove, the temperature of which is raised as rapidly as possible to 70° C, and this is maintained for two hours. Srd to 9th Operation. Liquoring. — Pad the cloth seven times in the open width through a solution of carbonate of soda at 4° Tw., and hang in the stove 440 DYEING OF TEXTILE FABRICS. [Chap XX. after eacli padding operation, maintaining the tempera- ture in each case for two hours at 75° — 77° C. In winter the padding liquors are made warm (35° — 40° C), but in summer tliey are always cold, since if too hot, oil is stripped off the piece to an excessive and injurious degree. In the course of regular working, the liquors soon become veritable oil-emulsions, and constant i^. 92. — Section of Liquor-padding iSIachine. oversight is necessary in order to maintain their specific gravity as constant as possible, and thus ensure ulti- mately a regular and satisfactoiy colour. A section of the liquor-padding machine of Messrs. Duncan Stewart and Co is shown in Fig. 92. It con- sists of a wooden box or tank a to hold the liquor, provided with rollers above and below. Over this are supported two paii^s of heavy squeezing rollers B c and D K At F a few straining bars serve to open out and stretch the cloth : g is the folder. The mode of passing the pieces through the machine is readily understood from the diagram. Cliap. XX.J ALIZARIN. 441 With resrard to the stoving, it is well to bear in mind that diirinor the first stashes of drying much va- pour is given off, and special attention must be given to ensure adequate ventilation. Fig. 93 is the ground plan, showing heating flues, and sectional elevation of a modern four-storeyed Turkey- red stove. A A repre- sent ordinary coal fires situated in the base- ment ; the hot flue- gases pass first through channels made of fire- brick, then through iron pipes, and finally make their exit to the chimney at B. The upper part of the stove is divided, by floors of iron-gi'ating, into several storeys C, D, E, F, each of which is furnished with wooden frame- work, supporting, one above the other, two pairs of horizontal rails provided with short, upright, wooden pegs. Over these pegs one selvedge of the 442 DYEING OF TEXTILE FABRICS. [Chap. XX. cloth is firmly hooked alternately from right to left, while the other is allowed to hang down : thus, when the stove is filled, each storey is closely packed with two tiers of cloth suspended in such a manner that the heated air from below can readily pass between each fold. A yam stove is similarly constructed, but in this case the ends of the rods holding the yam are supported on horizontal rails fi-ee from pegs. Another mode of hancrino: cloth, but one which is not so economical of space, is to have only one storey in the stova Above, near the roof, are fixed a number of strong, smooth, wooden i^ails, on which the cloth is sus- pended in long folds, reaching down to within one or two feet of the iron-ofratinsf immediately above the hot flues. In all cases efficient ventilation is secured by means of numerous side windows, which can be readily opened and closed at wilL lO^A Operation. Steeping. — Run the cloth in the open width through a machine consisting of a large vat divided into several compartments fitted with rollers above and below. The first compartments are filled with a solution of carbonate of soda at |^° Tw. (Sp. Gr. 1-0025), and heated to 40° C. The last is filled with water only. The cloth is then well washed, and di-ied in the stove at alKDut 65^ C. Wth to lith Operation. — These operations, con- sisting of mordanting., dyeing, and clearing, are precisely similar to those already described for yarn-dyeing. It may be well to state that the number of paddings in dilute soda solution (liquoring) varies according to the quantity of oil which it is desired to fix upon the clotL Good Turkey -red contains about 10 per cent, of modified oil on the fibre. 402. "Sulphated Oil Process" for Dyeing 500 kilos, of Yarn or Cloth. — In this process the frequent repetitions of passing the fabric through oil-emulsions or Chap. XX.] ALIZARIN. 443 sodium carbonate and then stoving are not used. The olive oil is replaced by an alkaline solution of sulphated olive or castor oil {see p. 234) with which only a single impregnation is necessary, followed by a steaming or stoving process. Is^ Operation. Bleaching or Boiling. — This is iden- tical with that already given in describing the previous processes for yarn and cloth. 2nd Operation. Preparing. — The dry cotton is thoroughly impregnated by "tramping" or "padding" with a cold or tepid solution of 10 — 15 kilos, of neutral- ised sulphated-oil (50 per cent.) per 100 litres of water. The excess is removed, and the cotton is merely dried in the stove, or it may be heated for 1 — 2 hours to 75^^ C. 2>rd Operation. Steaming. — The prepared and dried cotton is submitted to the action of steam, 2 — 5 lb. pressure, during 1 — 1|- hour. ^th Operation. Mordanting. — The cotton is worked and steeped for 2 — 4 hours in a tepid solution of com- mercial aluminium acetate (tin -red -liquor), or more economically in basic aluminium sulphate, AU(S04).,(0H).,, at 8°Tw. (Sp. Gr. 1-04). After mordanting, the excess of aluminium solution is removed by wringing or hydro-extracting, the cotton is dried and then either simply well washed in cold water, or first worked for half an hour at 40° — 50° C. in a chalk bath containing 20 — 30 grams of ground chalk per litre. A solution of sodium phosphate may replace the chalk water. Alkaline fixing -agents like ammonia and sodium carbonate are best avoided in case any of the oil-preparation should be stripped off. hth Operation. Dyeing. — Dye with 15 — 20 per cent, of Alizarin (10 per cent.), with the addition of 1 per cent, of its weight, of chalk or acetate of lime. The cotton is dyed in the cold for half an hour to ensure regu- larity of colour, the temiDerature is then gradually raised to 70° C. in the course of an hour, and the dyeing is con- tinned at this temperature till the bath is exhausted. 444 DYEiyG OF TEXTILE FABRICS. [Chap. XX. The cotton is then well washed (although with highly calcareous water this is best omitted), hydro-extracted, and dried. 6^ Operation. Second Preparing. — The dyed and dried cotton is again impregnated with a dilute solu- tion of neutralised solphated oil (namely, 50 — 60 grams of sniphated oil [50 per cent.] per litre), and then dried. This second preparing may also take place after the mordanting, the oil being then fixed by means of a second mordanting with a weak solution of basic alaminium sulphate, kc. 1th Operalioii. Second Steaming. — The dried cotton is steamed as before, for one hour. 8^» and 9th Operations. First and Second Clearing. — These may be identical with operations 13 and 14, described in the "Emulsion process," although many chemists think that soap alone should be used here, and consider that the addition of stannous chloride is altogether unnecessary if not irrationaL The ** sulphated-oil process " is comparatively so new, that numerous slight modifications of the process as here giren are naturally tried and adopted by -various dyers, and to some of these reference will now be made. The sulphated - oil used is invariably carefully neutralised, either with caustic soda or ammonia, Asa rule, ammonia is preferred, since even the addition of an excess of ammonia would have little or no injurious eflfect, owing to its volatility ; and further, the ammonia compound of sulphated-oil is more readily decomposed on steaming than the sodium compound, and a more com- plete fixing of the oil results. Either sulphated castor oil or olive oil may be used. Very good results are even obtained by the simple use of a carefully made castor oil soap, which, being excessively soluble, and giving thin solutions, is well fitted to impr^paate the fibre thoroughly. In the " preparing " process, the cotton does not at- tract or fix any of the oil It simply absorbs a definite 445 ^ -^ O bo a "a (U I Ph 446 DYEIXG OF TEXTILE FABRICS. ICh&y. SX. amount of the solution, and supposing sulphated olive oil to have been used, the prepared cotton contains the sodium or ammonium compounds of oxyoleic acid and of the glvcerine-sulphuric-ethers of oxyoleic and oxysteaiic acids, these being its constituent elements. It is very important to know the exact percentage of sulphated-oil contained in the solution, since it is this which determines the amount of oil and alumina ulti- mately fixed on the cotton, and consequently the beauty, brilliancy, and fastness of the colour. According to Liechti and Suida, the action of the Jirst steaming process is, to decompose the ammonium or sodium compounds of the ether constituent of sul- phated-oil into ammonium or sodium sulphate, glycerine, oxyoleic and oxystearic or trioxyoleic acid, according as olive or castor oil has been employed. The other con- stituent (oxyoleic or trioxyoleic acid) remains unchanged. At the same time the steaming causes a better penetra- tion of the fibre by these oxidised fatty acids. Some- times the steaming at this stage is altogether omitted. The decomposition of the compound ether referred to may also be eflected by heating the dye-bath to the boiling point instead of only to 70° C, the bath becomes acid, and the brilliancy of the colour is developed suddenly. Fig. 94 represents a steaming-chest for yam made by Messrs. Tulpin Freres, of Rouen. The hanks of cotton are suspended on square wooden rods resting on an iron skeleton-caniage or framework, and are capable of being turned during the steaming process to ensure every portion being efficiently steamed. The ii'on caniage is supported on wheels, so that it can be filled with yam and then run into the chest. The steaming-chest itself consists of a wrought-iron horizontal boiler, with a mov- able door at one end pro"^*ided with clamps. For the prevention of drops there is fixed internally and at the top a cover of sheet-copper, in such a manner as to leave a space between it and the boiler-plate. The chest is provided with a steam-gauge, safety-valve, and blow-ofi 447 m Fig. 95.— Plan and Elevation of Continuous Steaming-Chest. 448 DYEIXG OF TEXTILE FABRICS. LChap. XX. pipe. The steam enters by a perforated pipe rnrming along the bottom of the boiler, and ■vrhich is tisually covered with a perforated iron plate. Cotton cloth may be reeled and suspended on rods in a similar way, or it may be steamed in the continuous steaming-chest of Messrs. Duncan Stewart and Co., Glas- gow, represented in Fig. 9-5. It consists of an annular- shaped iron cylinder or chamber a B, in the upper part of which a series of brass radial rods c are caused to circulate slowly by means of the endless screw e driven by the engine d. The cloth (in the open width) enters the annular space through a pair of squeezing rollers at F. By an ingenious arrangement the cloth is suspended in long, loosely -hanging folds on the radial rods, is carried round the annular space, and makes it-- exit by a second pair of squeezing rollers at G. The chamber is constructed of boiler-plate, so that the goods can be submitted to high-pressure steam. Another form of contintious steaming - machine is that in which loose rods, supporting the cloth in a similar manner, are passed continuously by means of endless chains through a lai^ rectangular brick chamber filled with very low-pressure steam. If in the mordanting process the cotton was merely dried after the preparing with sulphated-oil, there ai^e pro- duced upon the fibre the aluminium compounds both of the ether and of the oxy- or trioxy-oleic acid ; but if it was also steamed, there is then fixed on the fibre essentially the normal aluminium compound of oxy- or trioxy-oleic acid (Liechti & Suida). A brighter colour is obtained by adding a small pro- portion of stannous chloride to the aluminium solution, or stannate of soda to the oil solution. Afrer mordanting and washing, a slightly basic aluminium salt remains on the fibre, its basic character being generally caused by the calcareous condition of the water. Traces of lime are also present. II previous to washing, a warm chalk bath is used, a much more Chap. XX.J ALIZARIN. 449 basic and more calcareous aluminium compound is formed. During the dyeing process there is probably formed the Alizarin compound of the basic oxy- or trioxy-oleate of aluminium and calcium just referred to. ^ If there is a deficiency of oil on the fibre, the brightest shades are always obtained by dyeing at the low temperature indicated (70° C), but otherwise the temperature may be raised to the boiling point, although there is then a tendency of a portion of the oily mordant being softened and boiled out, especially if it is in slight excess. With the use of pure Alizarin— i.e., the '-blue shade of Alizarin," as it is generally Called-^ a 'fiery brilliant red is not obtained ; hence such as contains Isopurpurin (An- thrapurpurin)— i.e., the ''yellow shade of Alizarin "—is generally preferred. The second preparing and steaming operations have for their object the neutralising of the basic compound present on the fibre at this stage. This operation of steaming after dyeing has a most remarkable eflfect in giving brilliancy and fastness to the colour, especially if the dyeing has been conducted at a low temperature. If 100° C. was employed, then the brightening effect has taken place to a considerable eS:tent, if not entirely, already in the dye-bath, as above mentioned. Sometimes the second preparing is omitted, and a small quantity of neutralised sulphated-oil is added to the dye-bath instead. The method of "clearing" described (seep. 434), in which the cotton remains stationary while the liquor cir- culates through it, gives very much better results than if the cotton Were Worked vigorously in the solution, since in this latter case much of the red-lake would be mechanically removed by friction, and the colour would look poor and weak. 403. The Action of Lime-salts in the Dye-bath. -^One of the most interesting facts comiected witli the D D 450 DYEING OF TEXTILE FABRICS. [Chap. XX. application of Alizarin, is the necessity of the presence of a lime salt in the dye-bath, in order to obtain a really good serviceable colour. The general result of researches made by Schlumberser, Rosenstiehl, and others, with a view to elucidate this point, seems to favour the idea that the AKzarin-red-lake, as fixed upon textile fibres, is not simply an aluminium compound of Alizarin, but one which also contains calcium as an essential constituent. The following results of Liechti and Suida's re- searches bearing on this point will expjlain this. Pure aluminium hydrate, whether in its precipitated form or fixed on the fibre, cannot be properly dyed with Alizarin except in the presence of lime compounds. Xormal aluminium phosphate behaves similarly. Xormal alu- minium alizarate [Al2(Cj^HgO^)3] is a purplish-red com- pound soluble in water, alcohol, and ammonia, Basic aluminium alizarates — e.g. [Alo(Cj^^HgOJ(OH)J and [Al^(Cj^HgO^)(OH)jn] — are, on the contrary, bright red compounds, insoluble in water and alcohol, and little soluble in ammonia, Aluminium-calcium-alizarates of very varied composition, prepared by dyeing aluminium hydrate with Alizarin in the presence of calcium acetate," are mostly reddish-brown insoluble compounds. The amount of lime-salt present in the dye-bath determines the quantity of Alizarin which will be taken up by the alumina, and the amount of lime taken up by the lake is determined by the quantity of Alizarin employed. The relative proportions of Alizarin, alumina, lime, and fatty acid present in the lake abstracted from Turkey- red and Alizarin-red- dyed cotton, vaiy considerably, ac- cording to the method of dyeing employed ; as a rule, a large excess of alumina, in proportion to the lime and Adizarin, is present. The above-mentioned authors find that alumina-mordanted cotton, when dyed with Alizaiin in the presence of calcium acetate, takes up ^ molecule of lime for each molecule of Alizarin, and they consider that the composition of the lake in unsoaped Alizaiin- Cliap. XX. j ALIZARIN. 451 red -dyed cotton is best expressed bv the formula [AlXa(Ci,HeO,)3(OH),]. 404. Another Method of Dyeing Alizarin Red on cotton, in use among calico-printers, but which does not give quite such ^ast colours as those described above, is given in the following resume: — 1. Mordant with commercial aluminium acetate, 5o_8o Xw. (Sp. Gr. 1-025 — 1'04), dry, and age for 1 — 2 days, by hanging in a chamber heated to 50° C, and having a somewhat moist atmosphere. During this ":igeing" process much of the acetic acid escapes, and alumina or a basic aluminium acetate is fixed on the fibre. 2. In order to fix the alumina more completely, work the cotton for a few minutes at 60° C. in a bath of phosphate, arsenate, or silicate of soda, 5 — 10 grams per litre ; then wash well in water. 3. Dye with Alizarin, and dry. A small addition of acetate of lime is used if necessary. Since the cotton at this stage contains no oil, it is essential to the obtain- ing of a bright colour, that the dyeing should take place at a temperature not exceeding 70° — 75° C. 4. Prepare with a neutralised solution of sulphated- oil, 50 — 100 grams (50 per cent.) per litre, and dry. 5. Steam for J — | hour, at 21b. pressure. 6. Clear as before. 405. Alizarin Pinks, Purples, &c., on Cotton. — Alizarin jnuks are obtained by precisely the same me- thods as are adojDted for reds. The aluminium mordant employed must, however, be considerably weaker — use, say, aluminium acetate at 10° Tw. (Sp. Gr. 1-05). Basic mordants are avoided, since they give uneven colours, and even normal aluminium sulphate may be used with advantage; the amount of Alizarin (20 per cent.) may be reduced to about 1 per cent, of the weight of cotton, and the proportion of oil-preparation re- quired is correspondingly diminished. The most pleas- ing pinks are those produced by using a " blue shade of 452 DYErSG OF TEXTILE FABRICS. [Chap. XX. Alizarin," i.e., one free from Isopurpurinj Flavopurpiirin, or PiirpuriiL Terv good fast shades of purple and lilac are obtained from Alizarin, either with or without the use of oil- prepai-ation : indeed, the use of oil does not seem to add any particular brilliancy to the colour, but serves mainly to fix the mordant, and to make the colour a little faster to boiling soap solutions. When the cotton is prepared with oil, according to either the Emulsion or Steiner's process for Turkey -red, it is mordanted, worked and steeped for a short time in a solution of ferrous sulphate at 3' — 4'' Tw. (Sp. Gr. 1-015 — 1-02); it is then allowed to lie over- night, and is finally well washed. The amount of iron precipitated on the fibre, and of Alizarin subsequently taken up in the dye-bath, is de- termined by the amount of oil previously fixed, and not merely by the concentration of the ferrous sulphate solution- For the darker shades of purple, therefore, the cotton should be well prepared with oil, while for pale shades the preparation is slight. The best and bluest shades are only obtained when the mordant is thoroughly saturated with Alizarin, any excess of uncombined mordant gives the colour an unpleasant dull-reddish appearance. The use of pyrolignite of iron gives somewhat darker, brighter, and bluer shades than the sulphate. Very deep purplish blacks are obtained, and with less oil-preparation, by steeping the cotton, previous to mordanting, in an infusion of gall nuts, or other tannin matter. After mordanting, the cotton is well washed and dyed with 5 — 15 per cent, of Alizarin (10 per cent,). If the water is not sufficiently calcareous, it is very essential to add the necessary quantity of chalk or acetate of lime to the dye-bath (1 — 2 per cent.). After dyeing, the cotton should be washed and soaped at a temperature of 60° C When not prepared with oil, the cotton is prepared with tannin, by working it in a cold infusion of tannin matter (equal to 1 — 2 grams of tannic acid per litre); it is ^^P- ^] ALIZARIN. 453 P 3oTw5''p'^?..?'^".'r ^^ r>jroli,mte of iron 1 -3 T^^. (^p Gr. l-OOo-l -015), and finally M-ashed. One may also mordant the cotton bj impregnating it with pyro Ignite of iron, 1°_3= Tw., wrin^inS out the excess, and then ^yorking it for ten minutes at ^50° C in a solution containing 20 cubic centimetres of silicate of soda 160 Tw. (Sp. Gr. 1-08) per litre, and finally washing L ^^^f ^^'^P^^T7;.\giTes greyish yiolets, FlayopurpuriS and Purpurin reddish yiolets, which are little esteemed _ Various shades of chocolate, claret-red, &c, are ob- tained wi h Alizarin, by mordanting th; oil-prepared cotton with a mixture of aluminium ami iron m^ordants either m the state of sulphates or acetates. Whether the cotton is prepared with oil according to the Emulsion or btemer s process, or by the Sulphated-oil method, it is adyisab e to work it in a weak tannin bath before mordan mg, especially for the darker and bluer shades, since a better proportion of iron is fixed by this means. Ihe different shades are produced by varyincr the relatiye proportions of aluminium and iron mordant remembering always to yary the concentration of the tannin bath m accordance with the latter After mordanting, the cotton is washed, dved with Alizai^, prepared with weak sulphated-oil, steamed and soaped, as already described. ' mnr^T^,^^ '^vf ' ""^ '^■^':'^'-^^ ^^7 ^Iso be obtained by 7JiTll^ . ^ '"^^ -^"^ ^^ chromium acetate, instead ot w th the mixture ot iron and aluminium salts Although Alizarin and Anthrapurpurin haye been mainly alluded to in the aboye, the other members of the anthracene group-namely, Flayopurpurin and Purpurin sTmXr sha'dt" " '"^''^^ ''' ^^"^ ^^'^^ ' ^^^ ^^' '^^ '^ 406. Applicatio7i to Wool.--Alizs.rm is capable of yielcung a number of pleasing shades on wool, according. to the mordant used, and ought to be largely employed wheneyer fastness to milling and to light is required. In conjunction with other colouring matters which are 45-1 r'TLIVG OF TEXTILE FAEEICS. [Chap. XX. sJTinilarly applieA. i: nay yield an endless variety of shades. I^- : - ~ A : - 'i - :\ ' : - \ ' - " " " ' ' _ no difficulty, - _ _ _ _ /_ . 12 cr3 int the "vrool ^th — - . 7.- : -Tim) and ' — : __ : : . ::•:.:: jr ii-r wool into : - : - - "^-T :-:^_ :_re gradually to the .„- : n ir, and contimie boiling ^ — ^ - :-- i. separate badiL, with K' - -: : -r ;:,-_..:. __ . . ;.nd 4 — 6 'percent, of acr - ; : r ;: -- — T - : _.- -_ : - : : - jxe an even colour it is "' - ~ : " - _■ - . . hour in the cold dye " : ' .-ature gradually in the "_~ . -_ : -i-Z, and boil a quarter ' - ' After dyeing, :_ --, -- -, _^ _ . : .T :: inthe open ' -gam of tartar to the mordanting ri.tial to the production of a full -iar teands to give intensity, but ' Le colour. Care must - _. 7 -phate used is free from - . T : . ; ~ of mordant the colour lacks " y, and if the deficiency is excessive .I -red is obtained. With excess of — tti. IS to become yellower and less and more orange shades are obtained .:! the aluiiiiii-.iin .-Til phate, 1 — 4 per : ride, ir. \ . „. r a further addi- - --' : :" iream oi LarLar is necessary. " ' - dye-bath of acetate of lime :.: :: _"::-jjid chalk) is also .: -7 " .^i-er employed is not :"_. :: lime, the colour is poor ■ -7 :-7- :_. is not exhausted ; with :iuller. - . _rs given by the various :..mily rfcriouring matters, it is _. .: .f yidlds a very blue shade of Chap. XX.] ALIZARIN". 455 red, or a claret-red ; Anthrapurpurin, a bright red ; Flavopurpurin, a somewhat duller and yellower red ; Purpiirin, a shade approaching that given by Alizarin, but much yellower, namely, a dull brownish-red. To obtain Alizarin-orange on wool, mordant the wool with 5 — 8 per cent, of stannous chloride (tin-crystals) and an equal weight of cream of tartar. Dye with 10 per cent, of Alizarin (20 per cent.) without the addition of acetate of lime. With the addition of 4 — 5 per cent, of acetate of lime a bright orange-red is obtained, but without, the colour is very much yellower. Excess of lime makes the orange still redder, but it is apt to be uneven. Alizarin- orange may also be dyed in a single bath. Alizarin gives a bright reddish orange ; Flavopurpurin a bright yellowish-orange. The colour yielded by Anthrapurpurin holds an intermediate place ; it is a bright orange. Purpurin gives a moderately bright orange-red. Yery rich claret-brown shades are obtained by mor- danting the wool wdth 3 per cent, of bichromate off^otash and 1 per cent, of sulphuric acid 168° Tw. (Sp. Gr.1-84). The addition of the sulphuric acid is beneficial, since it tends to give a somewhat yellower and fuller colour ; it is not, however, absolutely essential. Dye with 10 per cent, of Alizarin (20 per cent,). The addi- tion of 2 — 4 per cent, of acetate of lime to the dye- bath makes the colour somewhat less yellow, or bluer, though apparently slightly less intense. Strange to say, its addition is by no means essential, as in the case of the aluminium mordant for dyeing reds. Good colours are also obtained bv the single-bath method ; use 1 per cent. IvoCroO. and I per cent. HoSO^, 168° Tw. Kumerous fast shades of brown, olive, purple, &c., are obtained by associatinjj Alizarin with such colourinsr matters as Gallein, Coerulein, and many of the d\^e woods. The shades yielded by the different members of the Alizarin group with chromium mordant are as follows : Alizarin gives a dull purple colour ; Anthrapurpurin, a much redder shade, namely, a claret-brown ; Flavopurpurin, 456 DYEIXG OF TEXTILE FABRICS. [Chap. XX. a yellower shade of claret-brown ; Piirpurin gives . the most intense colour of all, namely, a deep claret-brown. Very good shades, ranging from bluish-^-iolet to slate, are obtained by mordanting wool with -4 — 8 per cent. ferrous sulphate and -i — 8 per cent, cream of tartar, and dyeing in a separate bath with 10 per cent. Alizarin (20 per cent.) and 5 per cent, carbonate of lime. With the single-bath method darker colotirs are obtained, but they are much browner and duller ; use 6 per cent. fejTOUS sulphate and 0'6 per cent, oxalate of potash. L'on-alum. employed instead of ferrous sulphate gives good results. Copper sulphate as the mordant gives claret-browns, either by the mordanting and dyeing method or by the single- bath method. With the use of amnioniacal sulphate of nickel and uranium salts, as mordants, Alizarin yields nice shades of grey and slate. Applicaiio)i to Silk. — Alizarin is as yet little used in silk-dveinor. Good colours may be obtained bv mor- d anting the silk according to the ordinary methods, and working it. after dveing, in hot soap solutioiL 407. Nitro-Alizarin. [Ci^H5-X0n'(0H)..]— This col- ouring matter, also called Alizarin Orange, is produced by the action of nitrous acid on .Alizarin. It is applied to the various fibres in the same way as Alizarin ; although it yields fast colours, it finds as yet only a comparatively limited employment. Application to Wool. — With aluminium mordant it yields very good orange colours. Mordant the wool with 6 — 8 per cent, of aluminium sulphate and 7 — 9 per cent, of cream of tartar. Excess of mordant renders the shade dulL The addition of acetate of lime to the dye-bath makes the colour browner. With stannous chloride mordant the colotir obtained varies very considerably, according to the amount of mordant employed. With a small amount (1 per cent, of stannous chloride and 1-5 per cent, of cream of tartar), a very reddish-orange is obtained ; with double the amount, Chap. XX.] ALIZARIN BLUE. 457 the colour becomes a yellowish-orange ; with 4 per cent, of stannous chloride, only a dull brown is obtained, the normal colour being evidently destroyed by the reducing action of an excess of mordant. The addition of acetate of lime to the dye-bath is not beneficial, since the yellowish-orange colour is thereby changed to brown. With stannic chloride (equivalent to 6 per cent, stan- nous chloride, SnClg'^HgO) an orange colour is also ob- tained. Excess of mordant does not destroy the colour as in the case of stannous chloride. With copper sulphate mordant a very good brownish- red is obtained. Use 4 — 6 per cent, of copper sulphate, without calcium acetate. With ferrous sulphate as the mordant a purplish- brown is obtained. Use 6 — 8 per cent, of ferrous sul- phate, without calcium acetate in the dye-bath. Bichromate of potash as the mordant yields dull brownish-reds. Use 3 per cent, of potassium dichromate and 2 per cent, of sulphuric acid, IGS*^ Tw. (Sp. Gr. 1-84). When potassium dichromate alone is employed, the colour becomes darker with increase of mordant, even till 16 per cent, be employed. 408. Alizarin Blue [C17H9NO J. — This colouring matter, also called Anthracene Blue, is derived from ]Sitro-alizarin by heating it with glycerine and sulphuric acid. It may be considered as the quinolin of alizarin, and has in consequence both basic and acid properties. It is met with in commerce in two forms, namely, as a paste containing about 10 per cent, of dry substance, and as a powder under the name of Alizarin Blue S. The former is insoluble in water, although certain com- mercial marks (WX, WR) possess some degree of solubility. The latter, which is, indeed, a sodium disul- phite compound of Alizarin Blue (Cj7ll9N04-2N'aHS03), is readily soluble in water, with a brownish-red colour. Its solutions decompose, if heated to 70^ C, with preci- pitation of the insoluble form of blue. With lime it forms an insoluble compound ; hence the presence of 45S DYEING OF TEXTILE FABRICS. [Chap. SX lime salts in the dye-bath must be avoided, otherwise there will be a loss of colouring matter. The insoluble form of Alizarin Blue may be applied in dveing, according to the indigo- vat method, by reducing it with zinc powder and carbonate of soda, or by the ordinary method of mordanting and dyeing in separate baths. When the latter method is employed, a certain proportion of disulphite of soda may be added to the dye-bath to render it soluble, or the dyeing at 100° C. niust be long continued. Avoid the use of copper dye- vessels. With Alizarin Blue S the mordanting and dyeing method only is employed. Application to Cotton. — Mordant the cotton with chromium according to the alkaline method. Dye in a separate bath with Alizai-in Blue ; raise the temperature crraduallv to the boiling point in the course of an hour and a half, and continue boiling for half an hour. Application to Wool. — The most suitable mordant to employ is bichromate of potash, in the proportion of 3 — 6 per ceiit. of the weight of wool. The addition of sulphuric acid, 168° Tw. (Sp. Gr. l-Si), is not beneficial if used in larger amount than 1 per cent. Dye in a separate bath with Alizarin Blue : raise the tempei^ture gradually to the boiling point, and continue boiling until a bright pure shade is obtained. AYith insufficient boiling the colourins: matter is only superficially attached to the fibre. The colour obtained is a bright indigo-blue, with purpKsh bloom. It is exceedingly fast to scouring, miU- m^, light, drc, and has the advantage of not rubbing off. When aluminium sulphate is the mordant employed a purplish-blue is obtained, which is very liable to be uneven unless gi-eat care is taken. Use 6 — 8 per cent, of aluminium sulphate and 5 — 7 per cent, of cream of tai-tar. With stannoiLS chloride mordant a much redder purple is obtained. Use 4 per cent, of staimous chloride (crystals) and 2 j>er cent, of cream of tai'tar. This mordant is not suitable for employing alone. Chap. XXI.] CACHOU DE LAVAL. 459 Ferrous sulphate^ as a mordant for Alizarin Blue, is also little suitable. It gives a greenish-blue colour, pos- sessing little brilliancy, and apt to be uneven. Mordant with 4 per cent, ferrous sulphate and 8 per cent, cream of tartar. Application to Silk. — Mordant the silk with alumi- nium or iron in the usual manner ; wash and dye in a separate bath with Alizarin Blue. Brighten the colour afterwards by boiling the silk in a soap bath. CHAPTER XXI. ARTIFICIAL COLOURIXG MATTERS CONTAINING SULPHUR. 409. Cachou de Laval (Poirrier). — This dyestuff is produced by fusing sodium sulphide with waste vegetable or animal matter. Care should be taken to preserve it from becoming damp by exposure, otherwise it is deteriorated, becomes more or less insoluble, and dissolves with a brown colour. It is specially applicable to cotton, and yields various buff and grey colours, which are very fast to acids and alkalis, and fairly fast to light. A2:)plication to Cotton. — Dissolve the dyestuff in boilins: water. The normal colour of the solution is a deep bottle-green ; if it is brown, add a little carbonate of soda, and boil for a short time. Avoid using calcareous water, either for solution or in the dye-bath, since this precipitates the colouring matter. If lime is present, acidify slightly with acetic acid. Add the colour solution to the dye-bath, also sodium sulphate in the proportion of 40 — 70 per cent, of the weight of Cachou de Laval. Dye the cotton for about half an hoiu', at a tempera- ture of GO'^ C, in a somewhat concentrated solution (100 grams per litre). Add the colour solution gradually. After dyeing, wash well, and work the cotton for 5 — 10 460 DYErS'G OF TEXTILE FABRICS. [Chap. XXL minutes, at 50° C, in a dilate solution of one or other of the following : — bichromate of potash, ferrous sulphate, copper sulphate, sulphuric acid, hydrochloric acid. Wash and dry. Cachou de Laval acts also as a mordant, so that Tarious shades can be obtained by dyeing afterwards in solutions of basic coal-tar colouring matters. Djewood extracts may also be appKed, since these are attracted by reason of the metallic oxide present in the finished Cachou colour. 410. Canarin (C3N3S3H). — This yellow colouiing matter is simply perthiocyanogen. It is produced as an insoluble powder when potassium thiocyanate (sulpho- cyanide of potassium) (C2f 'SK) is oxidised by potassium chlorate in the presence of sulphuric and hydrochloric acid. It is dissolved by boiling it with a solution of borax (100 grams per litre). It is specially adapted for dyeing cotton, on which it gives bright yellow or orange shades extremely fast to light, alkalis, acids, and hypochlorites. It acts as a mordant for basic coal-tar colouring matters ; hence pleasing compound shades may be obtained by ap- plying these in a separate bath. Application to Cotton. — ^Add to the dye-bath the necessary amount of borax Canarin solution and a small amount of soap. Introduce the cotton cold, and raise the temperature gradually to the boiling point. Rinse in cold water and dry. The use of calcareous water in dyeing must be avoided- Wool may be dyed in a similar manner. 461 APPLICATIOX OF THE MINEEAL COLOUEIXG MATTEES. CHAPTER XXII. CHR03IE YELLOW IRON BUFF MANGANESE BROWN PRUSSIAN BLUE. The mineral colouring matters applied in dyeing are extremely limited, and they are almost entirely confined to the vegetable fibres, the most notable exception in this respect being Prussian Blue, and this, strictly speaking, is not a mineral colouring matter. 411. Chrome Yellow.— Reference has already been made to the production of this colour, in describing the application of bichromate of potash and of lead salts to the cotton fibre {see pp. 207, 225). In^ addition to the methods there indicated, the following, specially intended for orange, may be used. Prepare a bath of plumbate of lime by adding a solu- tion of 15—25 kilos, of pyrolignite of lead to milk of lime contammg 20—30 kilos, of lime, and 500 litres of water. The mixture is well agitated, and then allowed to settle for about two hours. The cotton is worked, and steeped in the more or less milky supernatant liquid for 1—2 hours, then squeezed and washed. Dye in a cold or tepid (40^—50^ C.) solu- tion containing 5 per cent, of bichromate of potash, and i— 1 per cent, of sulphuric afcid, 168° Tw. (Sp. Gr. 1-84). Wash, and develop the orange colour by passing the cotton into clear, boiling, lime-water, then wash and dry. The cotton must be removed from the lime-water bath whenever the full orange colour is developed, other- wise the colour loses brilliancy. 412. Iron Buflf. — This colour simply consists of 462 DYEING OF TEXTILE FABRICS. [Cliap. XXII. ferric oxide. It is produced by first impregnating the cotton with a ferrous salt solution, then passing it through an alkaline solution^ to precipitate ferrous hydrate ; the latter is then changed into ferric hydrate by simple expo- sure to the air, or, preferably, by passing the cotton into a cold dilute solution of bleach in g-powder. Instead of a ferrous salt, one may also employ a ferric salt, e.g., ferric sulphate or nitrate. The cotton is simply impregnated with the ferric solution, then squeezed, and passed rapidly through a dilute solution of carbonate of soda, ammonia, or milk of lime. In this case, ferric hydrate is at once precipitated on the fibre, and no subse- quent oxidation is necessary. Iron Buffs are very fast to light and boiling alkaline solutions, but are sensitive to the action of acids. 413. Manganese Brown. — The production of this colour on cotton is briefly described on page 225 ; it is exactly analagous to the production of Iron Bufi" from ferrous salts. The process is simplified by adding a little sodium hypochlorite to a solution of caustic soda, passing the cotton impregnated with manganous chloride at once through this mixture. In this case, precipitation and oxidation take place simultaneously. It is very important always to use caustic soda free from carbonate, otherwise a little manganous carbonate is precipitated on the fibre, and since this compound does not oxidise readily, the colour is apt to be ir- regular. According to A. Endler, irregularity of colour may also arise from the unsuitable physical properties of the precipitate itself, when it is produced in the ordinary manner described. Endler obviates these defects by passing the cotton, after impregnation with manganous chloride, into a bath containing 25 litres of water, 7 litres of ammonia, and 500 grams of bichromate of potash. A somewhat unstable chromate of manganese is formed on the fibre, which, on decomposing, allows the chromic acid to react on the manganous hydrate and change it into Chap. XXn.] PRUSSIAN BLUE. 4(33 some higher state of oxidation. A final passa-e in dilute bleachlng-po^Yder solution completes the process. Manganese Brown is very fast to the action of licrht alkalis, and acids. ° ^ 414. 'Prnssia^nBlue.—ApplicatwntoCoUon.—Fruss^mn -Blue was formerly very much dyed upon cotton. Since the introduction of Aniline blues it has beenmuch less employed ^ ihe cotton is first dyed an Iron Bufi; and is then dved in a cold solution of potassium ferrocyanide, 20 ^rams ?«Qo T^' Ti*^' ^i'" ^'^'^^^^'^^ °^ ^^ ^^'^°^^ of sulphuric acid, M^I'/^'P^^"-^*^^^- ^'^sli and dry. The intensit; ot the blue depends upon the quantity of ferric oxide tixed upon the fibre in dyeing the bufl^: Fine purplish shades' of blue are obtained by working the cotton at 30° C. in nitro-sulphate of iron at 5° Tw° (fep. Gr. 1 -025) to which 2—3 per cent, of stannous chloride has been added, and then dyeing in a cold acidified solution of potassium ferrocyanide. Wash and dry; or it a still more purplish tone of colour is required, work tor a short time m a tepid bath containing Methyl Yiolet or Logwood liquor. Alkaline or boiling soap solutions readily decompose Prussian Blue, leaving brown ferric oxide on the fibre JKrolpnged exposure to sunlight causes the blue to fade but It IS restored if kept for some time in the dark ^^g/2ca^io?i to IToo^.— Prussian Blues (sometimes also called Royal Blues) are obtained on wool by means of red and yellow prussiate of potash, i.e., potassium ferri- and ferrocyanide. The former gives the best results. _ Ihe method depends upon the fact that when a mineral acid is added to solutions of either of these salts the corresponding hydro-ferri- or hydro-ferro-cvanic acids are hberated, and these, under the influence of heat, and by oxidation decompose and produce insoluble Prussian Blue. If then, wool is boiled in an acidified solution of these salts, the liberated acids are taken ui^ by the wool decomposition takes place gradually, and Prussian Blue IS precipitated, and becomes fixed on the wool 464 DYEIXG OF TEXTILE FABRICS. [Chap. XXH. The wool is introduced into a cold bath containing a solution of 10 per cent, of red prussiate of potash, and 20 per cent, of sulphuric acid at 168^ Tw. (Sp. Gr. I'Si) ; the temperature is gradually raised in the course of an hour to 100° C, and this temperature is maintained for ^ — | hour. The colour is rendered brighter and more purplish bv adding 1 — 2 per cent, of stannous chloride daring the last half to three-quarters of an hour of the boiling. Although sulphuric acid gives the best result, one may also use nitric or hydrochloric acid, in which case the shade of blue is modified slightly. Nitric acid, for example, makes the shade greener. It is very usual with dyers to employ a mixture of all three acids, especially when yellow prussiate of potash is employed. This mixture of acids, which is called *' royal blue spirits," or merely " blue spirits," may vary slightly in composition with different dyers. A usual mixture is the following: 4 measures of sulphuric acid 16S°Tw. (Sp. Gr. 1'84), 2 measures of hydrochloric acid 32° Tw. (Sp. Gr. 1'16), and 1 — 2 measures of nitric acid 61-^ Tw. (Sp. Gr. 1-;j2). When yellow prussiate of potash is employed, the use of nitric acid gives the best result, probably by reason of its oxidising action- For 10 per cent, of yellow prus- siate of potash use 8 — 12 per cent, of nitric acid 64° Tw. Instead of stannous cUoride in the ciystalline state, the dyer generally uses it in solution, as "muriate of tin." It is often sold to the dyer as " finishing blue spirits," though under this name it generally contains a slight ad- dition of sulphuric or oxalic acid, or both. These additions, however, are not essential. Another method of dyeing Prussian Blue, but one now seldom employed, is the following : — The wool is worked for two hours at 30° C., in a solution of feme sulphate 2° Tw. (Sp. Gr. I'Ol), con- taining 2 — 3 per cent, of stannous chloride, and 2 — 8 per cent, of cream of tartar. Tlie material is then well washed, and worked for two to thi'ee hours at 80° — 90° C, in a Chap. XXII.J PRUSSIAN BLUE. 465 bath containing 1 per cent, of yellow prussiate of potash, and 4 per cent, of oxalic acid, or sulphuric acid, 168° Tw. (Sp. Gr. 1-84). In the first bath there is fixed on the wool ferric oxide, which combines with the free hydro-ferrocyanic acid contained in the second bath. The depth of blue is regulated by the strength of the ferric sulphate solution, and the amount of yellow prussiate in the second bath should correspond to the amount of ferric oxide fixed upon the wool. Application to Silk. — Prussian Blue is now seldom dyed on silk, except as a groundwork for black. What was formerly known as Raymond's Blue was dyed as follows : — Work the silk in basic ferric sulphate (nitrate of iron), 5° Tw. (Sp. Gr. 1 -025), for a quarter of an hour, wring out, and let lie over-night. Wash well, and work for a quarter of an hour in a boiling soap bath containing about 10 per cent, of soap ; wash, and dye at 40° — 45° C., for ^ — ^ hour in a fresh bath containing 9 per cent, of yellow prussiate of potash, and 12 per cent, of hydrochloric acid, 32° Tw. (Sp. Gr. M6), and finally wash well. So-called " Napoleon's Blue " is a brighter blue, pro- duced as follows : — Work for half an hour in a cold bath containing 50 per cent, of basic ferric sulphate, 50° Tw. (Sp. Gr. 1-25), 10 per cent, of stannous chloride, and 5 per cent, of sulphuric acid, 168° Tw. (Sp. Gr. 1*84); wring out, wash, and work for half an hour at 40° C., in a second bath contain- ing 10 per cent, of yellow prussiate of potash, 2 — 5 per cent, of red prussiate of potash, and 12 — 15 per cent, sulphuric acid, 168° Tw. (Sp. Gr. 1-84). After wringing out from this second bath, the whole process is repeated. Previous to drying, the silk is softened and brightened by working it for half an hour in a cold bath containing an imperfectly made sulphated-oil. For one kilo, of silk, use a mixture of 150 grams of ohve oil and 15 grams, of sulphuric acid, 168° Tw. (Sp. Gr. 1-84). £ £ 466 THE DYEIXG OF MIXED FABRICS. CHAPTER XXIII. FABRICS OF COTTON AND WOOL. 415. Mixed fabrics, or unions, may be of the most varied charact.er. The wool and cotton may be inter- mingled througboTit the whole fabric ; or, what is more usually the case, each fibre may be confined to separate threads, forming either weft or warp. One large class, comprising Cashmeres, Coburgs, Sicilians, Alpacas, Delaines, ic, are thin, light materials, generally used for ladies' wear. These consist of cotton warp and woollen or worsted weft, and may well serve for illustrating the general methods employed in dyeing mixed fabrics. Such goods are made in two ways : — 1. The cotton warp may be dyed black, brown, dark blue, drab, asted in a pattern book, and references to each should be wTitten at the side. If all the different coloured swatches are then care- fully compared with each other, the following determina- tions may be made : — 1. The amount of tannic acid necessary to employ for obtaining a definite shade of blue. I Chap. XXIV.] EXPERIMENTAL DYEIXG. 477 2. The beneficial effect produced by drying or steam- ing of the tannin-prepared cotton is quantitatively determined, and it is at once seen how defective is the method usually employed of passing the material in its damp condition direct into the tartar emetic bath. The difference is specially noticeable in the soaped swatches. As to the proper concentration of the tartar emetic bath to be employed, this cannot be authoritatively determined on the small scale, but, of course, the aim must always be to thoroughly fix, or render insoluble, the whole of the tannic acid present in the fibre. By a few experiments on the large scale it will be easy to find what amounts of tartar emetic must be used, in order to leave as little excess as possible in the fixing-bath. If the goods pass through the bath in a continuous manner, they are, of course, only immersed for a very short time, and the solution must then be made more concentrated, and continuously replenished from a stock solution, in order to ensure the presence of a slight excess of tartar emetic. Only by experiments made on the large scale in the dye-works is it possible to deter- mine also what evil effects are produced by the passage of a large number of tannin-prepared pieces through the same tartar emetic bath. The addition of such salts as ammonium chloride, &c., to the fixing-bath, for the purpose of facilitating precipitation, may also be tried. One point still remains to be determined, namely, the proper temperature of the fixing-bath, and this may be ascertained by an additional series of experiments, similar to those instituted in the case of fixing Catechu by means of potassium dichromate. Stannic chloride, zinc acetate, &c., also precipitate tannic acid from its solutions, and if on economical grounds it is desired to substitute these for tartar emetic, the most favourable conditions of concentration, tempera- ture, &c., with respect to these, must be determined 478 DYEING OF TEXTILE FABRICS. [Chap. XXIV. according to the above metliod. Finally, parallel experi- ments must be made with the best methods of employing the dijfiferent fixing-agents, as previously determined, and the most convenient may then be selected. 429. Experiments with Colouring Matters. — Should the problem to be solved relate to the applica- tion of a coal-tar colour to wool or silk, one must determine whether the dyeing should take place in a neutral or acid bath. In the case of silk, one may try the utility of adding ''boiled-off" liquor to the bath, and, having determined the best amount to use, one proceeds, in the event of an acid bath being required, to determine the proper kind and exact amount of acid to add. One may also try the use of acid salts — e.g., alum, cream of tartar, &c. — instead of free acid. Here, too, experiments must be made to see whether it is better to dye in a cold or hot bath, or how high the temperature should be raised, and in what time the highest limit of temperature should be attained, tfec. In some cases, an alkaline dye-bath may be found the best — e.g., with Alkali Blue — on wool and silk. Since both these fibres are more or less attacked by alkalis, especially under prolonged influence and at a high temperature, (fee, it becomes imperative to make experi- ments for Ihe purpose of choosing the least injurious form and the minimum amount of alkali, also the proper temperature, duration of boiling, &c. In studying the application of such colouiing matters as require the aid of mordants, the necessary experi- mental work becomes even more diiOficult than in the cases already cited. The following considerations, for example, require to be taken into account : 1, the particular kind and amount, or concentration, of mordant to employ; 2, the conditions of mordanting — duration, temperature, &c. ; 3, the fixing of the mordant. As to the subse- quent dyeing, the experiments partake of the character of those already mentioned. As an illustration of the kind of experiments pursued Chap. XXrV.] EXPERnrEXTAL DYEING. 479 in respect of mordants, the application of an aluminium salt to cotton and to wool will now be sketched. 430. Experiments in Mordanting Cotton.— Cotton is scarcely ever mordanted with aluminium sulphate, but rather with aluminium acetate, for reasons which have already been given in the chapter on Mordants. The compound AL, S04(CoH30o)4 will be here considered. Several solutions containing this compound may be made, and of such concentration, for example, that they contain what is equivalent to 10, 20, 40, 60, 80, 100 grams of Al2(S04)3'18H20 per litre. Separate pieces of calico or cotton yarn are im- pregnated as evenly as possible with each of these solu- tions, and are then exposed for about two days to a moist warm atmosphere in an ageing chamber, in order to allow the acetic acid to evaporate. After such treatment there remains on the fibre a basic salt, of the composition AlgOg-SOg, which, neglecting the water of hydration, may also be represented thus : AljOs'SSOg + 2AI2O3. From this it becomes evident that for full and complete precipitation on the fibre, the latter should be passed through a weak alkaline bath, in order to remove the sulphuric acid still present. For this purpose, one may compare the use of silicate, arsenate, phosphate, and carbonate of soda or ammonia, or simply chalk suspended in water, &c. Of these salts, it is advisable to employ solutions of various degrees of concentration, but containing equivalent amounts of substance. Such several solutions are used both cold and at a temperature of 50°— 60° C. The mordanted cotton is well worked therein for 2 — 3 minutes, until thoroughly wetted, then washed well, and properly dyed, using a slight excess of colouring matter, e.g., Alizarin. It is advisable to dye for some time in the cold solu- tion, then to raise the temperature slowly, e.g., in the course of an hour, to 60° C. If the swatches seem not to take up any more colouring matter — i.e., if the mordant is saturated — they are well rinsed in water, and one half 480 DYEING OF TEXTILE FABRICS. [Chap. XXIV. of each is moderately well soaped. After drying, the various swatches are compared "vvith each other as to colour, and with a little practice one is soon able to determine which fixing-bath gives, relatively, the best result. In using Alizarin, it is well to remember that the dye-bath must contain a certain percentage of calcium acetate. 431. Experiments in Mordanting Wool. — Since the method of mordanting wool differs from that employed for cotton, experiments on the application of mordants to this fibre assume another form. With regard to alu- minium mordants, for example, the ordinary plan is to boil the wool with a solution of alum or aluminium sulphate, with the addition of cream of tartar, and one lias to determine the relative and absolute amounts of these constituents to be employed, in order to give, for example, the best red with Alizarin. For this purpose, six mordanting-baths are prepared, each containing, say, 1 litre of distilled water, and such amounts of Al2(SO^)3-18H20 as are equal to 2, 3, 4, 6, 8, 10 per cent, of the weight of wool employed. It is convenient to take 10 grams of wool for each vessel. The mordanting-baths are then simultaneously heated, so that their temperature may be raised to the boiling point, say in the course of one hour, and the wool is boiled for half an hour longer. The swatches are then well washed and dyed simultaneously in separate baths, with equal weights of Alizarin. The dyeing is conducted in a manner similar to that given for cotton, but it is here necessary that towards the end of the operation the wool be boiled. The addi- tion of calcium acetate to the dye-bath is also necessary. If excess of Alizarin has been used in the dye-bath, it should be removed by boiling the dyed swatches in dis- tilled water. After drying, the swatches are compared with each other, and the necessary amount of aluminium sul- phate to employ is fixed upon, e.g.^ ^ — 8 per cent. A Chap. XXIY.] EXPERIMENTAL DYEING. 481 second series of mordanting experiments should then be made, in which equal weights of wool are mordanted, say with G per cent, of aluminium sulphate alone, and also with the addition of increasing amounts of cream of tartar. It is convenient to consider the amount of aluminium sulphate employed as representing 1 molecule of the salt, and to add the cream of tartar to the several baths, in the proportion of 0, 1, 2, 3, 4, 6 molecules. The method of mordanting and dyeing is conducted exactly as already described, and on comparing the colours of the dyed swatches, it is easy to determine whether or not the addition of cream of tartar to the mordanting- bath has been at all beneficial, and, if so, which amount gives the best result. Since, in the case of wool and silk, the mordant may be applied before, after, or simultaneously with the colouring matter, other series of experiments must be carried out in order to determine which of these methods is the best. In comparing the dyed swatches, not only is the intensity, purity, brilliancy, regularity, CIm &b.) H2SO4. XaOH. KH4OH. Fibre little'Fibre at first^^bre orange- changed, li- violet, finallyl red, solution quid reddish* blue. | yeUowish-ied. violet. Liquid at first: colourless, af- terwar d sj bright Hue. Xo action. Madder. . Ck^chineaL Peachwood- Barwood. Sanderswood. Safflower. OrchiL Fibre brown- ish-red. Fibre br: j red, soli red- Fibre and 80- >ix lution purple.' Wool brown- ish-red, cotton not dianged. Fibre orange- Fibre and solu red, solution; tion bright orange-pint pink. i Solution purple. AswithXaOH. .Fibre dark red,Fibre brown, so- Much colour As withXaOH. solution pink, lution yeUowj extracted, changing tol bluish-red. brown. I Ck)tton almost decolorised. Xo action. Fi : re reddish- Fibre purplish, brown, solutionJ solution ool- dirty brown. ourless. AswithXaOH. Xo action- Cotton decolor- ised. Firre and s-^lu- Fir re p-orplisiu AswithXaOH. Uon reddish- solution col-j brown. ( ourless. Solution red. Cotton decolor- ised. With dilute Cotton, flesh- XaOH, cotton: colour, pale yellow. I Fibre and solu-iFibre bluish-^ with Xa OH. tion purple,] purple, afterward) brown. TABLES OF COLOUR TESTS. 505 (continued). S11CI2 + HCl. Alcohol. On heating, Little or no fibre becomes action, almost colour less, or pale lilac. Other Tests. Little colour extracted. Fibre and so- lution orange red. Fibre and so- lution bluish- red on heat- Fibre unchang- ed, solution red. Fibre unchang- ed, solution red. No action. No action. HNO3 gives a violet spot which afterwards becomes brownish with a faint blue border. It is not affected so readily by Hif O3 as the Crocein Scarlets are. Nitric acid colours fibre bright yellow. Nitric acid colours fibre yellow. Pale yellow so- 1 Nitric acid colours fibre brownish-yellow. Boiling lution. Eed solution. soap solution removes much colour, solution bluish- red. Nitric acid colonrs wool dark olive. Red solution. [Nitric acid colotirs wool dark olive. Boiled with FeS04 colour becomes violet Cotton straw yellow. At once de- colorised. No action. Bluish-red so- lution. See Magenta. 506 DYKING OP TEXTILE FABRICS. YELLOW AXD Colouring Matter. HCl. H2SO4. NaOH. NH4OH. Picric Acid. Colour extract- ed on "boiliog, ! liquid green- 1 isli-yellow. Decolorised.- Fibre becomes Fibre becomes orange, solu- paler, a yellow tion yellow. colourextract- ed on boiling. Victoria Decolorised, Yellow. •wflshing re- stores the co- lour. Naphthol Yellow. Decolorised I almost com- i pletely. AswitbHCL Fibre orange, solution yel- low. Fibre paler, yellow colour extracted on boiling. Naphthol Yellow S. 'Fibre bleacbed, I solution co- ! louxless. Deoolorised- Fibre paler, Fibre little liquid yellow. I cbanged, li- ! quid pale yel- Ic'-w. Aurantia. Chryso'idine. (b. s. & s.) Fibre pale Fibre yellow- Little or no No action. 1 yellow. isb-drab. efiect. Fast Yellow. (basf) Orange 3. (F. Baever & Co.) Fibre red. Yellow colonr Fibre paler Fibre yellower. extracted- I and vellower. Eed. Fibre brownish- i Solution ' Little action, red, liquid red.j brownish-yel- low. I Fibre red, li- Fibre and liquid Fibre dull yd- Fibre not quid pink. 1 bright bluish- lowish red. changed, li- red. quid slightly yellow. TABLES OF COLOUR TESTS. 507 OEAXGE COLOURS. SnClo+HCL AlcohoL Other Tests. Fibre "bleached, Yellow coloxrr ^U Picric Acid yellows taste bitter. the liquid CO- extracted. ^^^^^'^ ^^^^ ^^^ solution fibre becomes lourless Fibre bleached, the liquid co- lourless. red through the fonnation of isopurpuric acid. In compound colours the cloth should be extracted with alcohol, and the solution tested for Picric Acid with KCN. "Warm water extracts the colour. Yellow colour Water extracts the coloor and the yellow solution is extracted. ! decolorised by HoSO^. Boihng KCN extracts a red colour. "Wrapped in white paper and heated to 120^ C, leaves a stain on paper. Bleached. No action. Boiling water extracts nothing. Heated to 120' C. in white paper, leaves no stain. Fibre brown Colour readily Heated with SnClo gives dark brownish-red colour, on heating. I extracted. | afterwards decolorised. Almost decol- Yellow colour! orised. i extracted. Fibre bri ght A little colour HNO3 gives a bright red spot, red, after- extracted. wards decol- orised. Completely A little colour bleached. 1 extracted. 608 DYEING OF TEXTILE FABRICS. YELLOW AND ORANGE Colouring Matter. Orange 4. (A. Poirrier) HCL Fibre reddish- violet, liquid violet. Orange 2. (A. Poirrier) H2SO4. As with Ha. Phosphine. Fibre and li-As with HCL, Fibre deep red NaOH. No action. NH4OH. quid red. bluish but bluer. Fibre not changed, li- quid yellow. No action. Fibre nearly Solution green- Fibre becomes Fibre becomes decolorised, solution yel- low. ish-yellow. paler and yel- lower. Nitro- alizarin. Fibre pale Fibre brownish-!Fibre claret- Cold, no action; paler, a bright yellow. Madder. . straw yellow. solution low. yel- Little action. Old Fustic. . yellow, liquid yellow. red or brown- hot, as with ish, liquid colourless. Fibre brownish-' Fibre and so- red, solution lution purple red. Fibre and so- Fibre and solu- lution orange.; tion brown. NaOH, but fi- bre not so dark. Fibre brown. Fibre little' Fibreunchang- changed. ed, solution yellow . Young Fustic. Fibre unchang- Fibre and solu- Fibre reddish- As with NaOH. I ed, solution tion reddish- brown. pale yellow. Weld. iFibre little af- fected, solu- tion pale yel- low. brown. Fibre brownish- yellow. Fibre little af- fected, solu- tion pale yel- low. No action. TABLES OP COLOUR TESTS. 509 COLOURS {continued). SnCl2 + HCl. Alcohol. Other Tests. At first fibre Yellow coloui- becomes deep! extracted violet on beat- 1 ing, gradually ligbter and fi- nally bleacbed Compl etely bleached. No action. Fibre nearly A little colour decolorised. extracted. Fibre deep yel low, liquid yellow. Fibre un- changed, solu- lution pale red. Fibre orange, solution col- ourless. No action. Fibre Uttle af- fected. No action. No action. No action. No action. No action. HNO3 gives a bright yellow spot. Boiling Ba(0H)2 colours the fibre claret-red. Heated with FeaCle fibre becomes olive-brown. With HNO3 fibre pale yellow. Heated mth FeoClg fibre becomes olive. Boiled with acetate of alumina gives yellow solution with bluish-green fiuorescence. With HNO3 fibre dark brown. Heated with Fe^Cl^ fibre becomes olive. HNO3 no action. Heated with Fe2Cl6 fibre becomes olive. jColour unchanged by boiling with lead acetate. 510 DYEING OF TEXTILE FABRICS. YELLOW AXD ORANGE C'"'loMring I Matter. I HCl. H2SO4. Quercitron Fibre little af - iFibre brownisli- Bark. j fected, solu-j yellow, solu- I tion yellow. tion yellow. Flavin- Persian Berries. Turmeric. Annatto. . Iron BufF. Fibre and so- Fibre and solu- I lution yellow.! tion yellow. Fibre unchang- Fibre orange- NaOH. KH4OH. Fibre little Fibre uncbang- changed,solu- tion yellow Fibre and solu- tion yellow. ed, solution vellow. Fibre little af- fected, solu- tion yellow. ed, solution yeUow brown, solution greenish- yel- low. Fibre reddish- Fibre reddish brown, solu- brown, solution tion less. colour- brown. Fibre unchang- Colour slightly ed, solution brownish-yel- low. extracted. Fibre bright Fibre bright reddish - { reddish - brown, solu- tion orange- brown. Little affected. Fibre and solu- or brownish-; tion blue. red- Fibre straw- ! yellow or de- colorised. Little action. Chrome Yellow. brown, solu- tion orange. Little affected. lAs withNaOH No action. No action. Fibre decolor- Fibre greenish- Fibre paler,: Little action. ised, solution yeUow or dull liquid pale, pale yellow. yellow. yellow. TABLES OF COLOUR TESTS. 511 COLOURS {continued). SnClo + HCL Fibre little af- fected, solu- tion yellow. Fibre brovm- isb-yello-sv, so- lution bright yellow. Fibre brown, solution yel- low. AlcohoL No action. Other Tests. No action. With HNO3 fibre Hght brown. Heated with Fe2Cl^ fibre becomes olive. Colour becomes orange by boiling with lead acetate. With HNOs fi'bre dark brown. [Heated with FeoClg fibre becomes olive. ■Boiling acetic acid g^ves yellow solution with green fluorescence. Colour becomes orange by boiling with lead acetate. No action. |With HNO3 fit»re brown. Heated with FesClg fibre becomes olive. Colour becomes orange by boiling with lead acetate. Fibre reddisb-i Colour extract- With HNO3 fibre pale yellow brown, solu- tion colour- less. ed solution Boracic acid added to HCl and alcoholic solution, ' I gives bright red colour, orange or yel- lo wwith green fluorescence. Decolorised, j Solution bright "Dyed blue with KsFeCyg + HCl. yeUow, Decolorised. No action. Decolorised. No action. Fibre blackened with ammonium sulphide or H2S. 512 DYEING OF TEXTILE FABRICS. GREEN Colouring Matter. HCL H2SO4. NaOH. K:a40H. Malachite Green. Fibre and li- quid bright orange ; on washing with water the green colour is restored. Fibre much bleached, liquid blight orange. Decolorised. Decolorised. Methyl Green. (basp) Fibre and li- quid pale yel- low ; colour restored on washing. Fibre much bleachedjliquid colourless. Decolorised. Decolorised. Acid Green. (Soc. Chem. Ind.) Fibre pale green. Fibre brown, liquid yellow. Decolorised. Decolorised. Alkali Green. Fibre dark olive - green, solution red- dish-brown. Fibre and solu- tion dark brown. Decolorised. Decolorised. EelvetiaGreen Liquid yellow ; green colour restored on diluting with water. Decolorised. Fibre buff-yel- low. AswithNaOH. Ccerulein. (BASF) Fibre duller green, liquid claret-red. As with HCl, liquid dirty amber yellow. Xo action. Ko action. TABLES OF COLOUR TESTS. 513 COLOURS. S11CI2 + HCL Alcohol. Fibre almost Green colour decolorised, extracted, liquid yellow. Fibre almost Bluish - green decolorised,' colour ex liquid yellow, tracted. Other Tests. Heated to 100° C. colour does not change to bluish* violet. (Distinction from Methyl Green.) Fibre almost Green colour decolorised, readily ex- liquid yellow. Fibre not changed, blu- ish-green co- lour extracted tracted. Almost com- pletely deco- lorised. Fibre brown- ish-red, liquid brown; on washing with water colour gradually re- stored. ' H H Green colour extracted. Bluish - green colour ex- tracted. Heated to 100° C. becomes bluish-violet. (Distinction from Malachite Green.) No action. HNO3 gives a brown spot. 514 DYEING OF TEXTILE FABRICS. GREEN COLOURS Colouring Matter. Aldehyde Green. HCl. Fibre brigM yellow. Vat Indigo and Fibre paler, Old Fustic, liquid blue. Vat Indigo and Yellow remov Chromate of edatDnce,blue Lead. Indigo Car- mine and Pic- ric Acid. afterwards ; liquid dull yellow. Fibre at first blue, after wards very pale ; liquid blue. Cbxome Green. No action. H2SO4. Fibre orange. As with HCl. Fibre dirty yel- lowisb- green. As \^tli HCl. No fiction. Little action, fibre after- wards paler. Fibre greenish blue, liquid yellow. NaOH. Yellow remov ed; liquid pale yellow. NH4OH. At first little ac- tion, afterwards bleached. Fibre paler or blue, liquid yellow or greenish. No action. Fibre almost As with NaOH. decolorised. liquid yellow. pale No action. No action. BLUE ■ "-^ -,. Alizarin Blue. Fibre violet, Dilute H2SO4; Fibre (BAsr) fibre violet, li quid slightly red. Concen- trated HoSO gives Hquid. violet No action. TABLES OF COLOUR TESTS. 515 (eontinued) . SnCl2 + HCl. Alcohol. Other Tests, Slowly de- Green colour HNO3 gives a Lrown spot, colorised. extracted. Fibre much paler, liquid greenish yellow. Fibre becomes at first blue, afterwards decolorised. See indigo. Decolorised. No action. See indigo. No action. Boiling glacial acetic acid gives green solutiou ; on diluting with vrater blue is precipitated. Boiling Al2(S04)3 gives yellow solution with green fluorescence. Remove yellow colour by boiling with dilute Na2C03, and test the blue remaining for indigo. Ash contains lead* Blackened by (NH4)2S. Bleaching-powder solution changes colour bo yellow. Cold water extracts Picric Acid, test solution with KCN. Boiled with a solution of bleaching-powder gives yellow liquid containing chromate. Occurs only on calico prints. COLOUES. Fibre at first violet, on'h eat.' ing brownish red, liquid ia brown. No action. HNOs gives a bright yellow spot which goes brown after a time. Soap aad bleaching-powder have no action. Phosphoric acid gives orange-red solution, which on diluting with water and adding NH4OH becomes blue, dilute ammoniacal alcoholic solution shows characteristic absorption stripes when examined with spectroscope. 516 DYEIXG OF TEXTILE FABRICS. BTX'E COLOURS Colouring Matter. HCl. H2SO4. XaOH. ^'H40H. Soluble Blue. Extracts blue Fibre and liquid Fibre reddish- Decolorised at (b. s. & s.) colour. reddisb-browu. brown. once. Spirit Blue. . (A. Poirrier) Fibre dark Fibre and solu- green, solu- tion brownish. tion reddish- brown. Fibre brick red. D ecol or i Bed slowly. Alkali Blue Fibregreenish- Fibre and liquid Fibre at first Decolori sed 3B. (basp) Induline. Fibre violet, liquid deep blue. blue, solution reddish -brown reddish - almost colour- less. Met hyl eneFibre nearly Blue. decolorised. (basf) solution bluish green. on standing. I brown, after- wards decol- orised. Solution dark blue. rapidly. Reddish - violet As withNaOH. colour ab- stracted, the solution de- colorised on addition of 2inc powder. Violet colour restored by exposing fil- tered solution to the air. Fibre an d liquid Fibre bluish- green. violet. No action. TABLES OF COLOUR TESTS. 517 (continued). S11CI2 + HCL Alcohol. Other Tests. Fibre little Absolute changed, blue colour extrac- ted. hoi, even on boiling, ex- tracts no col- our. alco-SNOg gives a dark spot, which changes to dark g^een with a black border. Fibrenot chan- Absolute alco- ^^^^^s gives a black spot, which changes to dark 1 •■ . . ■■ , -. STfiATl- gad, liquid colourless. hoi the extracts colour, even in the cold. green. Fibre not chan- Absolute alco- HNO3 gives a light green spot with black border, ged, liquid! hoi extracts colourless. Extracts a vio let or green colour. Decolorised. the colour, even in the cold. Bluis h- violet III d^ili^e NN is not changed by bJeaching-powder rnlmirpxtTflrt ' solution. COiOur extraci- -g^Q^ gives a dark bluish-green spot, ed. Bleachmg-powder solution changes some Indulines to a reddish-grey, whilst others are decolorised. Greenish- blu e HNO3 gives a green spot which does not chaBge colour extract- f'l^ther. Bleaching-powder solution turns it first J " green, and gradually decolorises it. 6d. Qii cotton it is much faster than aniline blues, and withstands neutral soaps, light, and weak bleach- ing-powder. Very sensitive to chromic acid. A 3 per cent, solution of K2Cr207 changes it first to violet and finahy decolorises it. If it has been fixed with tannin a brown coloiir is left. 518 DYEIKG OF TEXTILE FABRICS. BLUE COLOrRS llatter. HCL H2SO4. NaOH. irH40H. Eesorcin Bine. i Dilute H^SO^, Solution blue, no action- 1 with red fluo- ' rescence. AswithNaOH. Indophenol Blue. Fibre grevisb- Fibre greyish-. No action. bro"WTi. brown. I No action. Vat Indigo Blue. No action. Dilute H2SO4, no action- Concentrated H2SO4 gives a blue solution- No action. No action- Indigo ^ Carmme. .Solutiongreen- ifih-blue. Solution blue. jFibre greenish. On boiling vrith dilute NaOH colour abstracted, so- lution little coloured, but becomes blue on acidifying. AflwithNaOH. Pmssian Blue. No action. No action. Fibre brown on heating. No action. Logvood Blue. Fibre red or brown, solu- I tion red. Ajs with HQ, Fibre and so- AswithNaOH. lution purple, i Ultramarine Decolorised. Blue. No action- TABLES OF COLOUR TESTS. 519 (eoniinued). SnCl2 + HCl. Alcohol. Other Tests. Decolorised. Blue colour Boiled with olive oil purplish colour is extracted, extracted. On heating^P.oiling a"bso fibre becomes paler, solution greenish- yel- low. Chloroform extracts blue colour. 1 ^-L 1 Strong HNO3 gives bright yellow spot. ^ -"^ ^'-''^'^■'- Indigo-dyed cottoji if burnt gives olf purple vapour. lute gives blue so- lution, which on standing becomes co- lourless with separation of indigotiu.. Fibre decolor- ised on heat- ing. which can l»e condeiised on a cold porcelain slab as a blue spot. No action. Fibre and solu- tion at first red, after- wards brown. Little or no col- ^*^^°^^ extracted by boiling with dilute NaaCOa ; _, J J i silk or wool mav be dved in the acidified solution. OUT extracted. _jfitric acid gives yeUow spot. No action. No action. Decolorised. No action. Ash contains iron. Concentrated nitric acid gives green spot. Boiled with XaOH, solution contains potassium ferrocyanide, on acidifying and adding Fe2Cl6 blue precipitate is obtained. If used for topping vat indigo blue, it can be removed by boiling with dilute HCl, the indigo being un- aifected thereby. On burning fibre blue-coloured ash remains. Only met with on calico or woollen prints. 520 DYEING OF TEXTILE FABRICS. VIOLET Colouring Martyr.' HCl H^.S04. XaOH. Is^H40e:. GalleiiL . . Fibre brown-! isb-red, liqtiid' amber-yellowj Afi with HCL ColoTir of fibre bluer. ' No addon. AlizariiL . . Pilre and li- quid d-jll yel- low. As with HQ. Colour of fibre bluer. No action- Methyl Violet Fibre vellow- isb - browa, liquid aTnber- yellow ; the violet colour! restored on' diluting vrith •water. Ab with HCL Fibre at first pale reddiph- violet, after- wards decol- orised. Fibre pale lilac, nearly decol- orised. Benxyl "Violet. Fibre yellow- As with HCL ish - brown, liquid amber- yellow ; the Tiolet colour restored on dilutiiis' "with Fibre at first Almost de co- bluer, after- lorised, fibre wards deool- pale bluish- orised. lavender. Parkin's T%re unchan-Xittle ot Violet. ged, solution action- bluish-pink. . noFibre blue, j colour re- I stored on wayb il ls'. No action. Naphthyl- amine Violet. Fibre grey. Little or no Phenyl Violet,Fibre dark or i green, solu- Spirit Violet. I tionbrownish. Fibre and solu- tion reddish- brown. Decolorised. Decolorised. TABLES OP COLOUR TESTS. 521 COLOURS. S11CI2 + HCl. AlcohoL Other Tests. Fibre crimson, liquid red. No action. HNO3 gives a bright yellow spot. Bleaching-powder solution has no action. As with HCl. No action. Destroy the colour by boiling with dilute HCl, wash and add NaOH ; the Alizarin remaining on the fibre is dissolved with purple colour. Fibre green, but nearly de- colorised on standing, li- quid yellow- ish-green. Colour ex- tracted. Fibre bright green, liquid pale yellow. Colour ex- tracted. Fibre dirty brown, but not decolo- rised. Colour ex- tracted. HNO3 ^^^ no effect. CI bleaches the colour slowly. Blue colour ex- tracted; only decolorises slowly. Colour ex- tracted. HNOs gives a green spot. 522 DYEING OF TEXTILE FABRICS. BLACK Colouring Matter. HCL H2SO4. KaOH. im40H. Aniline Black, Xo " a'ction, or colour be- comes green- ish-black, re- stored by al- kalies. Acid solution brownish. As with HCl. No action. Xo action. Logwood Black. Fibre red or olive- brown, solution deep red. As with Ha. Solution pur- ple. AswithXaOH. Woaded Black. Logwood col- our removed, indigo not affected, and fibre remains blue. As with Ha. Logwood col- our removed, indigo not affected. AswithXaOH. Alizarin Black. Fibre orange, colour restor- ed with XH3. As with Ha. Xo action. Xo action. Tannin Black. Bleached to pale straw colour, steep- ing after- wards in XH3, gives reddish- brown colour. As with Ha. Fibre brown- ish-grey or black. Xo actiou. TABLES OF COLOUR TESTS. 523 COLOURS. S11CI2 + HCl. AlcohoL Other Tests. Fibre greenish- Boiling alco-'Bleacliiiig-powder solution changes colour to brown- firrev colour liol extracts a, ^sn-reci. ^^c + '^^^^ -k^ V ^^^- \. T Several passages through a concentrated solution of r e s 1 r e d b y brownish - red B3In04 and oxalic acid alternately, decolorise it. rs H3. colour. Weak oxidising agents have.no action. Fibre violet or greyish - red, solution red, afterwards brown. No action. Ash contains iron or chromium. Fibre becomes As with indigo- ^i^t remove Logwood colours, etc., "by boiling with dirty green- ish-blue. blue. As with HCl. Decolorised. dilute HCl, and test blue remaining for Indigo. No action. No action. Ash contains iron. Ash contains iron. Occurs only on printed calico* 524: DYEING OF TEXTILE FABRICS. BEOWN Colouring Matter. HCL Alizarin. Fibre brown- ish-orange, colour restor- ed by XH3. H0SO4 As witli HCl. NaOH, NH4OH. Action slight, Fibre fibre bluer, changed, liquid tinted blue. un- Nitroalizaxin. Fibre paler, li- Fibre darker, Fibre darker,' No action. Catechu Brown. quid yellow. liquid orange. solution ourless. col- Little or noLittle or noLittle or noLittle or no change, sola- change, tion pale oransre. Camwood Brown. Fibre red, li- quid yellow- ish-red. As with HCL change. change. Fibre and li- quid purple. Fibre purple, I liquid colour- I less. Peachwood 'Fibre and li- Fibre yellow- Fibre purple, Fibre purple, Brown. quid yellow- ish-red, liquid liquid cherry- liquid colour- ish-red. yellow. I red. 1 less. D y e w d Brown. Red or purple, colour ex-] tracted, I As with Ha. Little change, Fibre unchang- liquid tinged ed, liquid tin- red, ged red. Bismarck Fibre reddish- As with HCl, Fibre brownish Fibre onchang- Brown. brown, solu-, but darker. ! yellow solu- ed, solution tion red. i tion colourless, brown. Phenyl Brown. Colour extract-' ed, solution brownish-red i Naphthyl- Fibre brown- amine Brown. ish-yeUow,so- ! lution oransre. Manganese Slowly decolor- Brown, ised. Purplish -.Eeddish-brown brown colour colour ex- extracted. tracted. Fibre yellow. No action. Xo action. TABLES OF CeLOUR TESTS. 525 COLOURS. S11CI2 + HCl. Alcohol. Other Tests. As with HCl. No action. As with HCl. No action. Fibre becomes paler, solu- tion colourless or orange. No action Ash contains chromium and sometimes copper. Colour more or less bleached by boiling solution of bleaching-powder. Fibre and li- quid cherry- red. ... Occurs orJy on wool. Fibre and li- quid cherry - red. Fibre redder, solution red- dish. No action. Ash contrfiins aluminium and iron. Fibre almost decolorised. Red or pink colour ex- tracted. Boiling water extracts colour ; boUing glacial acetic acid still more, with yellowish-green fluorescence. Fibre reduced to pink, solu- tioncoloiuiess. Dark brown- ish-red colour extracted. Fibre purple, solution pale pink. Solution blu- ish-pink. Rapidly de- colorised. No action. Ash contains manganese. 526 DYEING OF TEXTILE FABRICS. CoMPATlISOy OF ThF.RMOJiCETER SCAiES. {Approximate. ) Centigrade. FalireiilLeit. Centigrade. Fahrenlieit Centigrade. Fahrenlieit- 100*' 2120 1 72«> 162° i 44« 111'' 98 208 70 158 42 108 96 205 68 154 40 104 94 201 66 151 38 100 92 198 64 147 36 97 90 194 62 144 34 93 88 190 60 140 32 90 86 187 58 136 30 86 84 183 56 133 28 82 82 180 54 129 26 79 80 176 52 126 24 75 78 172 50 122 22 72 76 169 48 118 20 68 74 165 46 115 Comparison of degrees Twaddell and Specific Gravity. In order to change degrees Twaddell into Specific Gravity, multiply bv 5, add 1,000, and divide by 1,000. Example. — Change 168° Tw. into Specific Gravity. 168x0 840 1,00 l,000 )l.840 1-84 Spec. GraT. To change Specific Gravity into degrees Twaddell, multiply by 1,000, subtract 1,0*00, and diride by o. Example. — Change 1'84 Spec. Grav. into degrees TwaddelL 1-84 x1,000 1,840 1.000 5 ) 84 1680 T#. D. H. HJLL LIBRARY North Carolina State College MEASURES OF LENGTH, WEIGHT, AND CAPACITY. 527 Measures of Length. The Metre, the unit of length, is the ten-millionth part of a line drawn from the Pole to the Equator. 1 millimetre 1 centimetre y-^i 1 decimetre =z J^th, „ 1 metre = as above 1 decametre =: 10 metres 1 hectometre = 100 „ 1 kilometre = 1,000 „ Y^^^tli of a metre =: 0-03937 inches. 0-39370 „ 3-93708 „ 3-2809 feet. 10-9363 yards. 109-3633 „ 0-62138 miles. Inch = 2-53995 centimetres. Yard= 0-91438 metres. Foot = 3-04794 decimetres. Mile = 1609-32 metres. Measures of Weight. The Gram, the uiiit of weight, is the weight of a cubic centimetre of distilled water at 4° Centigrade 1 milligram 1 centigram _ .^-^ 1 decigram = -J^th „ 1 gram — : as above 1 decagram = 10 grams 1 hectogram =: 100 „ 1 kilogram = 1,000 ,, T^oth of a gram =z 4h 0-0154 troy grains. 0-1543 „ 1-5432 „ 15-4323 „ 154-3235 „ [pois. 3-5291 oz. avoirdu- 2-20462 lbs. .. Pound (avoirdupois) = 453-59 grams. Ounce (avoirdupois) = 28-34 „ Measures of Capacity, dry and liquid. The Litre, the unit of the measures of capacity, dry and liquid, is the volume of a cubic decimetre. 1 millilitre = ^ iwoth of a litre, or ) j 15-432 grain measures, or ; 1 o^.h.n .c.r.i-;rr.^^,.^ t — I 0-06103 cubic inches. = 0-61027 „ „ = 6-10270 „ „ = 1-7608 pints. = 2-2009 gallons. = 22-0097 .. ( 1 cubic centimetre 1 centilitre == yiyth of a litre 1 decilitre = J^th „ „ 1 litre =/^® above = 10001 \ cub. cent. 1 decalitre = 10 litres 1 hectolitre = 100 ,. I 1 kilolitre = 1,000 „ = 220-0967 ,'; A gallon of water weighs 10 lbs. (avoirdupois). INDEX. A CETATE of lime, 245 ■^ Acetic acid, 244 Acid potassium tar- trate, 243 Ageing process, 170 Albumen, 237 Alizarin pink, 451 • — ijurple, 452 — chocolate, 453 — blue shade, 426 — yellow sh.ade, 426 — oil, 236 — Ajiplication to wool, 453 silk, 45C cotton, 426 Alizarin, 425 — orange, 455, 458 — blue, 427 Alpaca, 27 Alum, 163 Aluminate of soda, 175 Aluminium acetates, 164 — chloride, 173 — mordants, 157 — nitrate, 174 — oxalate, 174 — siilphate-acetates, 167 — sulphates, 157 — tartrate, 174 — tMocyanate (sulpbo- cyanide), 172 — thiosulphate (hypo- sulphite, 175 Amaranth, 376, 422 Ammonia, 241 Ammonium carbonate, 241 A'uyloid, 6 Aniliae black, 890 — grey, 387 Annatto, 355 Anthracene colours, 425 — green, 407 — violet, 406 Anthrapurpurin, 426 Antimony potassium oxalate, 242 tartrate, 242 Argol, 243 Assistants, 243 Auramiue, 385 Aurantia, 401 Aureosin, 404 I I Aurin, 403 Auro-phenylene, 402 Azariu, 418 Azo blue, 419 Azo colours, 412 Azoflavin, 416 Azuro phenylene, 402 T)AEBEEET, 367 ^ Barium cliromate, 211 Barlow's bleacliing kiers, 79 Barwood, 310 — red, 341 Bastose, 20 Bengaline, 387 Benzopurpurin, 416 Bichromate of jjotash, 206 soda, 211 Black, Auilinp, 390 — Bonsor s, 329 — Copperas, on wool, 327 — liquor, 178 — on cotton, 319 silk, 333 -wool, 323 Bleaching of calico, 75 cotton yarn, 72 linen cloth, 88 yaro, 86 silk, 118 — • — wool, 112 Blooming, 197, 274 Blue, Alizarin, 457 — Alkali, 379 — B!ackley, 379 — China, 379 — Cotton, 379 — Coupler's, 387 — Diphenylamiue, 377 — Elberfeld, 387 — Ethyl, 377 — Ethylene, 397 — Fast, 379 — Fluorescent, 402 — Gentiana, 377 — Guernsey, 379 — Humboldt, 377 — Imperial, 377 — Lyons, 377 — Methyl, 377 Blue, Methylene, 396 — Naphthol, 410 — Napoleon's, 465 — Navy, 379 — Neutral, 389 — New, 390 — Nicholson's, 379 — Night, 379, 386 — Opal, 377 — Parma, 377 — Peacock, 384 — Prussian, 463 — Quinoline, 398 — Kaymond's, 465 — Eesorcin, 402 — Rosaniline, 377 — Koubaix, 387 — K yal, 463 — Sers^e, 379 — Soluble, 378 — spirit, 357 — stone, 222 — verdigris, 223 — Victoria, 386 — vitriol, 222 — Water, 379 Boiled-ofl: liquor, 116,247 Boiling-oS silk, 116 Bordeaux, 422 Brazilian cotton, 2 Brazilwood, 338 Brown, Bismarck, 413 — Cinnamon, 413 — Fast, 421, 422 — holland, 89 — Manchester, 413 — Manganese, 462 — Phenyl, 399 — Phenvlene, 413 — Orchil, 418 Buff, Irou, 461 Burl dyeiug, 468 pACHOUDE LAVAL, ^ 459 Calcium acetate, 245 — carbonate, 242 Camwood, 340 Canarin, 460 Canelle, 413 Carb nate of potash. Manufacture of, from raw wool, 40 Carbonising, 32 530 DYEING OF TEXTILE FABRICS. Cardinal, 376 Carmines, 196 Casein, 239 Cashmere, 27 Castor-oil as a mordant, 235 soap, 236, 444 Cateclin, 368 — Experiments %rith,473 Caustic soda, 240 Cellulose. 4 Cerise, 375 Chalt, 242 Chemical theory of dve- ing, 145 ChemicMng, S3 Chemistry of retting, 16 China grass, 21 Chocolate, Alizarin, 453 Cholestertne, 38 wool, 323 — yellow, 461 Chrome- alum, 211 — blacks on cotton, 321 Chromium acetate, 215 — chloride, 218 — mordants, 206 Alkaline, 219 — nitrate, 218 — -nitrate-acetate, 218 — sulphate, 214 — -sulphate-acetate, 217 — thiocyanate (sulpho- cyanide), 218 Chrysamein, 420 Chrysamin, 419 Chryseolin, 418 Chrysolin, 403 Chrvsoidine. 412 Chrvsoin, 418 Claret red, 422 Coccin, 404 — New, 422 Cocciuin, 423 Cochineal, 34S — crimson, 348 — scarlet, 349 Ccerulein, 407 CodiUa, 17 Collodion, 7 Colorimetry, 492 Colour acid and colour bases, 153 Colouring principles, 147 Comparative dve-trials, 493 Complementary colours, 490 Compound shades, Dye- ing of, 489 Copper acetate, 222 Copper chloride, 223 — chromate, 211 — mordants, 222 — nitrate, 223 — sulphate, 222 — sulphide, 223 Copperas, 176 — black on wool, 327 Corallin, Eed, 403 — Yellow, 403 Cotton, Action of acids on, 6 alkalis on, 8 chlorine on, 11 colouring mat^ ters on, 12 frost on, 6 lime on, 10 metallic salts on, U mildew on, 5 — Chemical composition of, 4 Cotton-bleaching, 71 — cloth -drying machi- nery', 267 — cloth- dveing machi- nery, 260 — cloth -washing ma- chinery, 262 — Dead, 3 — dyeing. Notes on, 248 Operations, &c., in, 249 — Microscopic appear- ance of, 3 — Mordanting of, 150 — plant, 1 — Physical structure of, 2 — Sea Island, 2 — Unspun, drying ma- chinery, 250 — Unspun, dyeing ma- chinery, 250 — Unspun, washing ma- chin er^-, 250 — yam drying machi- nery, 259 dyeing machinery, 250 washing machi- nery, 254 Crabbing, 111 Cream linen, 89 — of tartar, 243 Crocein, Brilliant, 423 — 3 Bs. 422 — Scarlet, 423 Cross-dyeiner, 466 Crystal carbonate, 241 Cutch, Prepared, 370 Cyanosine, 405 DAHLIA, 377, 382 Dead cotton, 3 Dead wool, 30 Defects in indigo vats, 312 Dextrin, 7 Dip. The, 87 Dolly, 103 Drying-arrangement, Open air, 2S2 Drrine-machine, Cylin- der,^2S6 Hank, 259 Hot-air, 268 Loose wool, Mc- Nauffht's, 277 Tenter, 2S7 Wool, Continuous, 278 Dunging process, 170 Dyeiug, Irregular, 287 Dyeing - machine, Bo- den's hank, 252 Mather and Piatt's spiral, 261 — — Pitt's wooUen yam, 280 Union cloth, 283 Warp, 253 Wilson's hank, 251 Winch, 282 Woollen yam, 279 if^CEU silk, 119 -^ Egyptian cotton, 2 Elasticity of silk, 57 Emulsive oil, 234 Eosin, 404 — Methvl, 404 — Ethvi, 404 Erythrin, 404 Erythrosin. 404 Experimental dye ves- sels, 483 — dyeing, 473 Experiujents in mor- danting cotton, 479 wool, 480 — ■• with colotu'ing mat- ters, 478 Extracting, 32 FASTNESS of colours, 485 Fast and fugitive co lours. List of, 487 Ferric acetate, 191 nitrate, 192 INDEX. 531 Ferric chloride, 192 — nitrate, 191 sulphate. 190 — sulphate, 178 acetate, 192 Ferrous acetate, 178 — chloride, 181 — nitrate, 181 — siilphate, 176 — thiosulphate (hvpo- sulpbite), 181 Fibroin, 63 Firing of tin spirits, 202 Fixing agents for mor- dants, 239 — liquor, Purple, 179 FJavaniline, 397 Flavin, 363 Flavopurpurin, 426 Flax, 12 — breaking, 16 — Chemical composi- tion of, 19 — hackhng, 17 — scutchiug', 17 — retting, 14 — hue, 17 — plaut, 12 — Physical structure of. 17 — tow, 17 Fleece-wool, 30 Fluorescein, 403 Flurt silk, 51 Fugitive colours, 485 Fustic, Old, 369 — Young, 364 riALLElN, 406 ^-^ Gallocjanin, 411 Gas bleaching, 112 — singeing, 77 Gelatin mordant, 239 Glauber's salts, 245 Glossing, 55 Glucose, 7 Glue as a mordant, 239 Grassing, 89 Greasy wool, 35 Grey, Aniline, 387 — sour, 80 — washing, 78 Green, Acid, 374 — Aldehyde, 396 — Alkali, 37o — Anthracene, 407 — Benzaldehyde, 373 — Benzoyl, 373 — Brilliant, 373 — Ethyl, 373 — Guinea, 375 Green, Helvetia, 375 — Light, 375 — Malachite, 373 — Methyl, 383 — Naphthol, 402 — New, 373 Victoria, 373 — Solid or Fast, 373 — Victoria, 373 — vitriol, 176 Grenadine, 375 Gun-cotton, 7 TTAIE and wool, Dif- -*"•- ference between, 24 Hank -dyeing machine, Boden's, 252 — Wilson's, 251 Hank- washing machine, Scotch, 255 German, 257 Hawking machines, 315 Helianthin, 415 Hehochrysin, 401 Huile toumante, 234 Hydro-cellulose, 7 — -extractor, 281 Hydrogen dioxide, 112, 114, 120 Hyposulphite of soda, ■^26 TNDIGO Carmine, 317 -•- —dyeing operations, 313 on cotton, 297 silk, 317 wool, 304 Theory of, 295 — extract, 317 on silk, 318 wool, 317 — grin^ling mills, 296 — hydrosulphite vat. 30i — lime and copperas vat, 297 — potash vat, 307 — soda vat, 308 — substitute, 325 — urine vat, 308 — vats. Defects in, 312 — woad vat, 303 — zinc powder vat, 302 Induhne, 387 Injector bleaching kier. 81 Iron alum, 193 — liquor, 178 — mordants, 176 Alkaline, 193 Iron, Nitrate of, 181 191 — PyroUgnite of, 178 Isocholesterine, 38 Isopurpurin, 426 JIGGER dyeing ma- " chine, 262 Jute, 20 — bleaching, 21 TT-EMPS, 26 -•-^ Keratin, 30 T AC dye, 354 ^-^ Lactarine, 239 Lant, 92 Lead acetate, 224 — chromate, 211 — mordants, 224 — nitrate, 224 — Sugar of, 224 Level-dyeing, 276 Light, Influence of, ou dyed colours, 485 Limawood, 488 Lime-boil, 78 — -sour, 80 Linen bleaching, Che- mistry of, 90 — cloth bleaching, 88 — Cream, 89 — fibre, 12 — yam bleaching, f^G Liqiiid bleaching, 114 Llama-wool, 27 Logwood, 319 — blacks on cotton, 319 silk, 333 wool, 323 — blues on cotton, 323 wool, 331 — greys on cotton, 322 — purples on cotton, 323 wool, 332 Loose-wool scouring, 94 Lut^cienne, 404 nVTADDEE, 344 ^^^ — bleach, 75 Madras cotton, 2 Magdala red, 389 Magenta, 375 — Acid, 376 Magma process, 101 Magnaneries, 44 Mandarin S., 420 Manganese mordants, 225 Manganous chloride,225 Market-bleach, 85 533 DYKDfG OF TEXTILE FABRICS. M elf «wghf 8W00I ■eonr- ii«»adiiie.]flO Kensensed cottnan, 9 Meta^edlie acid, 19, 90 MelBstaudc aeid. HB Ifetiiods oC vool-dje- IGDiB?, bfluenee o^ OB dyed ookmis, 481 ifiiEfMi faiV^f^^ D jeiae o£.4B6 Mohair, 27 Moano^caietie eoloazxBg mi«as,l«7 Mondaatiiis aad ^eii^ meOiod of «oo1-4f^ — Geaenl vetiiods oC, 149 HotdaBt^laS 137 •^ Clmndiiiit, 806 — Copper, 2SS — GaiK;^9 — InHB,]^ — 00,233 — Sbtm^ae -^Sol^pluD^ 296 — Tnune add, 227 JEoIlMnj alk, 4i MoDoiga^ aeouniig pto- mass*Bf!f^si^lS5 'S- Olae acid, 233 OliTe oil as a mordant, 23S — /LWa phtliAl. 4an — DimedijlaidliK. 4U — DipjieDjlamiBe, 415 — eTtrt,4ai> — G — IIL,415 — IV„415 — G,4ai» — 11.415 — Pa]atm^401 OK]nl,£5 QrgBDxiae alk. 48, 50 Oraeaiin, Ho. 3, 421 Orer-duooiii^ 203 Onxgroira wool, 30 Oxjedlnlase, 11 PSACHWOOB, 33S Peetie acid, 4^ 16 PeeliBe,16 Feeto9e.l6 Posaaa berries, 3S6 Pcmrint eotton, 2 nieno] coToor8,308 Flilaxiii.4ifB Vhosfidae, 3B6 F1ijaie,aOI Pioie acid, 398 Pieoe-dyed goode^ 289 ^SaeotB,lfir Pink. Afiarin, 451 — enriii^^ iiaoior, ^1 — r -e,3S8 :-Tiiiw% T^ P]rroai]i.40& QCTEBCITBOS hmr\, 362 J^AIIIE.21 Bavs[Ik,43 — wool, 35 Bed,JLBisal,^3 — Bar«ood,3ll — C2ar^422 — Coufpo, 416 — Coxallin. 403 — Fastv423,4a — Frenidi, 430 -Impoia], 4M — liqnar, 168 ConinioB, 169 Halloo — Magdala, 389 — STeutxal. 389 — Peony, 403 — Pliaietol,48S Beting, S7 'Resin.hwl, 83 B^tins of flax, 14 Blieea«21 Booemne, ^^ BosMiilrne eatoms, 373 Sose Bemeal, 404 — JB.404 BosdJBe^375 Booolaae, 387 Sostdie aeid eoloiixB, 408 Bonge fxants^s, ^O £oaiIle,182 Bobeofiine, 404 BalBdin,^l Bahiiie, 375 SAI)DX;5IN6,2ai Safiroa y«]low, 400 — >r---JM,389 — indiiliiiegrai^oC :. c40 P:: 4i» »_■-- Z -aU^ INDEX. 533 Scarlet GG, 421 — GT, 420 — Imperial, 423 — E, 420 — 2E, 421 — 3R, 421 — 4R, 421 — 5R, 423 — 6E, 422 — S, 423 — SS, 423 — Xylidine, 420 Schappe-silk, 51 Scouring agents, 92 — of loose wool, 94 union goods, 108 woollen-clotli, lOS yarn, l(_i2 Scroop, 53 Scutching of flax, 17 Seek, 94 Sericin, &4 Silica as a mordant, 226 Silicate of soda, 241 Silk, Action of acids on, 66 alkalis on, 67 colouring mat- ters on, 69 metallic salts on, 68 water on , 65 — Blacks on, 333 — bleaching, 118 — Boiled-off, 115 — Chemical com.posi- tion of, 62 — cocoon, 47 — conditionin?, 59 — Culture of, 43 — dyeing— indigo, 317 — -j; Notes on, 294 — Ecru, 119 — glue, 64 — lustreiug, 57 — Microscopic appear- ance of raw, 46 — Mordanting bath for, 186 — Origin of, 43 — Physical properties of, 53 — Eeeling of, 49 — scouring, 115 — scroop, 63 — Souple, 117 — Squeezing machine for, 187 — Stretching of, 117 — - Srrin^ing of, 55 — washing inacbine, 189 J J Silk weighting, 371 — Wild, 51 Singeing of calico, 76 Single -bath -method of dyeing, 273 Skying, 300 Soda, Caustic, 240 — crystals, 241 Sodium arsenate, 210 — carbonate, 241 — dichromate, 211 — hydrate, 240 — phosphate, 240 — sulphate, 21^ — tetrasiUcate, 241 — thiosulphate, 226 Soluble glass, 241 — oil, 2S6 Souple silk, 117 [261 Spiral dyeing machine. Spirit, Amaranth, 198 — Aniline, 203 — Bar>vood, 201 — Blue, 464 — Bowl, 199 — Cotton, 201 — Crimson, 201 — Finishing, 198 — Plum, 198 — Purple, 201 — Eoyal blue, 464 — Scarlet, 199 — Scarlet finishing, 198 — YeUow, 198 Sprits, 89 Squeezing machine, Birch's, 266 for woollen cloth, 284 — rollers, 265 Stan ate of sorla, 204 Stannic chloride, 199 Staunous chloride, 195 — niti-ate, 198 Staple of wool, 23 Steiner's process of Turkey - red dyeing, 438 Stoving, 112, 431 Stretching of silk, 117 — woollen-yarn, 102 Stringing, 55 Stufliug and saddening method of dyeing, "^71 Suoar of lead, 224 Suli^hated oil, 234 Sulpho-muriate of tin, 198 Sulphur as a monlant. Sulphuric acid, 245 Sulphur stove, 113 Sun gold, 401 Snper-argol, 244 Surat cotton, 2 Sweeteuing, 83 rriANNIC ACID as a -*- mordant and filing agent, 227 Experiments with, 475 Tartar, 243 — -emetic, 242 — substitute, 244 Tartaric acid, 243 Tenacity of silk, 57 Theories of dyeing, 144 Thiosulijhate of soda, 226 Tin composition, 201 — crystals, 195 — mordants, 194 — Muriate of, 195 — Nitrate of, 199 — Nitro-muriate of, 201 — Oxymuriate of, 201 — salt, 195 — spirits, 197, 200 ^- siDots, 352 — Sulpho - muriate of, 198 Tram silk, 48, 50 Tramping, 429 Tropaeolin D, 415 — G, 415 — O, 418 — OO, 415 — 000, No. 1, 419 — 000, No. 2, 4J0 — 0000, 420 — E, 418 — Y, 418 Turkey-red bleach, 85 clearing, 4 i4 — — dyeing. Emulsion process, 427 oil, 236 stove, 441 — , Steiner's pro- cess, 438 — , Snlphated oil process, 442 , Calico-printer's process, 451 liquor-padding ma- chine, 440 — — oil -padding ma- chine, 439 — — \aru steaming chimber, 445 Turmeriii. 2S7 634 DYEING OF TEXTILE FAEP.ICS. Turn-liauking, 90 Tussur silk, 51 bleaching of, 119 UNION goods, Sco.ir- iug of, 108 Dyeing of, 4G7 ir-.iripe coccon, 3 Uranin, 403 VACUUM bleacliiii ,' * Mer, 81 Vat, H.vdrosulphite, 308 — Ferroiis sulphate, 297 — Potash, 307 — Soda, 303 — Urine, 303 — Woai, 303 — Ziuc powder, 302 Verdigris, 223 Vesavine, 413 Vicmia wool, 27 VinegLir, 244 Violaniline, 387 Violet, Acid, 383 — Alk.ili, 383 — Benz.\ 1-rosaniline, 383 — Crystal, 386 — Hofmann'?, 382 — Imperial, 381 — Methyl, 382 — Naphthvlamine, 396 — Neutral, 389 — New Fast, 411 — Paris, 382 — Parma, 381 — Perkiu's, 3S7 — Phenyl, 381 — E,osauiliue, "381 — Spu^t, 381 Viridin, 37 • WAEP-DYEING m:i- chine, 253 Wash stocks, 254 Washing machine, Cahc-., 263 German hank, 257 Scotcu hank, 255 Square beater, 265 — of loose wool, 277 woollen cloth, 285 — — woollen yarn, 281 Waste silk, 60 Water, Alkaline carbo- nate as impurities in, 127 — Calcareous and niag- nesian impurities in, 122 — , Correction and iniri- fication of, 1Z8 — purification, Clark's process, 131 Gaillet-Huet pro- cess, 134 Porter-Clark pro- cess, 133 — Ferruginous, 126 — Unranic impurities in, 127 — Peatv acids in, 127 — Soft and hard. 121 Weiarhtin? silk, 371 Weld, 356 Whitening, 242 White-sour, b4 Wdd silks, 51 Woaded blacks oa wool, 330 Woad-vat, 303 Wool, Action of acids on, 32 alkalis on, 3! colouring' mat- ters on, 34 heat on, 31 nietalhc salts on, 34 — analysis, 36 — Blacks on, 323 — Chemical comp^si- tiou of, 30 — Conditioning of, 28 — -dyed goods, 289 — dveiag. 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The Merry-go-Round. Original Poems for Children. Illustrated throughout. 5s. Bo-Peep. A Book for the Little Ones. With Original Stories and Verses, Illustrated throughout. Boards, 2s. 6d. ; cloth gilt, 3s. 6d. The World's Lumber Room. By Selina G.\ye. Illustrated. 3s. 6d. The " Proverbs " Series. Original Stories by Popular Authors, founded on and illustrating well-known Proverbs. With Four Illustrations in each Book, printed on a tint. is. 6d. each. Fritters. By Sarah Piit. Trixy. Bv Maggie Symington. The Two 'Kardcastles. By Made- line Bcnaria Hunt. Major Monk's Motto. By the Rer. F. Langlwidge. Tim Thomson's TriaL By George Weatheriv. Ursulas Stumbling-Block. ByJuHa Goddard. Bntli's Life-"Work. By the Rer. J osei^i Johnson. The World's W^orkers. A Series of New and Original Volames. With Portraits printed on a tint as Frontispiece, is. each. General Gordon. By the Rev. S. A. Swair:e. Charles Dickens. By his Eldest Daug^hter. Sir Titus Salt and George 3uOore. By 1. Bumley. 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May Cunningham's Trial The Top of the Ladder : to Reach it. Little Flotsam. Madge and her Friends. The Children of the Court. A Moonbeam Tangle. Maid Marjory. SeUctions from Cassell