fell F r;;;, ,-,►*,--•. -j^ss^^^ *2.-6b .<=c-«.-^ «-^ <»»_> NEARLY KEADY, Cloth Gilt, Pbice Five Shixlings, Elaborately ami Piofusely Illustrated bv The brothers DALZIEL, uniform with th- Boy's Book ofLvdistriaJ Infokhatiox. IJTLlNES OF CEEATIOK. By Elisha Noxce. The object of the Author is to give a simple, clear, and lucid ilcscriptioi^ of the Universe under the following divisions :— The Sky. The Earth. The Vegetable KiuL-dom. The Air. Tlie Waters. The Animal Kingdom, London : WiKD &. Lock, 1.5s. Fleet Street. .^^ ^m"" ci^--^ THE BOY'S BOOK OF INDUSTRIAL INFORMATION. BY ELISHA NOYCE. ILLUSTRATED WITH THREE HUNDRED AND SIXTY-FIVE ENGRAVINGS, BV THE BROTHERS DALZIEL. LONDON : WAKD & LOCK, 158, TLEET STEEET. 1858. Digitized by tine Internet Arcliive in 2010 witli funding from NCSU Libraries littp://www.arcli ive.org/details/boysbookofindustOOnoyc PREFACE. Ix putting tliis work before tlie public, tlie Author has eudeavoiu'ed to supply a clear and brief description of the materials, processes, and apparatus made use of in the various examples of industry and skill constantly before our eyes, so that the reader may acquire a knowledge of such things, and an interest in those, who, by their hard work and patient ingenuity, supply them ; for every article and process can be made to have a value and an interest, in proportion to the amount of knowledge we possess respecting them. There is no attempt in this work to describe every article and process, but such only as are most interesting and instructive. All the mere trades and handicrafts — the results of which are so various, and depend so completely upon the skill of the artisan, that any description of their particulars woidd scarcely be profitable or interesting to the reader — have been avoided. The illustrations of this work have been prepared with the greatest care, and drawn from reality. By the kind permission of Lord Paumiu'c, the artists ^^l PREFACE. were alloTved to make ■whatever drawiugs "vrere necessary in the Arsenal at Wool"wich ; and thanks are due to many of oui' eminent manufactni'ers for similar favours with respect to their several factories and machinery. In the first division of this work have been placed all those materials -which exist in natm'e, either isolated or combined; and "which have merely to be extracted or separated, as the earths^ metals^ &c. Under the second di-vision, " Manufactured Products/' such results of manufacture as are known by the common designation " stuff," and are of an uniform and parricular quality, as soap, soda, &c., not existing in Nature as such. In the third division, indiridual articles, the result of skilled labour', each compounded and made up of several sub- stances, or of particular forms. In the fomth section are the processes made use of in the production of the various necessaries or elegancies of life. Some of these might have been placed under the second and third divisions, but the Author thought proper to place them here, on account of the processes being more readily described than theii' results. The fifth dirision is devoted to the most usual forms of Apparatus and Machinery of general application, avoiding all mere tools and machines for specific purposes. The last division is a mere outline of those important engineering works which of late have acquired an increased interest from the addition of railways and electric telegraphs to their number. B'TRODUCTIO^'. The inquiring mind uses all its senses to obtain some new idea, and to apply it to some useful piu-pose ; it is this spirit of research that has led to all the great results in -\rt and in the mechanical and chemical sciences, which Ave now enjoy and admire ; but it is only by very slow degrees, and by great perseverance, that such results are obtained, although the accumulation of a few years makes an enormous aggregate.' Look back a generation or two — where was then the steam engine, where the tall stalks which indi- cate the sites of complicated and ingenioiis manufactures ? the blacksmith then worked at his anvil, and wrought out with his hands what he required in iron ; but what is now done with this treasure of the mine ? behold the Leviathan and the Britannia Bridge, — count their thousands of tons of plate iron rolled out by machinen% and think of the work of their removal, the millions of rivets to fix them together, the elevation of the one, and tlie laxuaching of the other. Coidd this be done without that macliinery which has become gradually perfected by thought and perseverance ? Visit the iron works and see the powerfid " steam hammer " moulding into form a mass of red-liot iron, many tons in weight ; see the powerful and beautiful contrivances for rolling into plates, drawing into bars and wire, or cutting up this stubborn metal, and call it stubborn no more! See the powerful " locomotive " carrying along the trams hundreds of tons of goods at a rate that can hardly be equalled by the bird that flies through the air on its light pinions; and the huge steam ships which cut their rapid X IXTEODrCTIoy. way across tlie seas, holding in contempt those very winds upon which alone the mariner used to depend I See with what rapidity and accuracy almost every kind of " textile " material is produced by the steam-worked loom, and remember that these have all arisen, with hundreds more, from small beginnings, and step by step. Xor does the mechanical genius boimd the works of civilisation. From stud^Tng the various properiries of the elements of natui'e, and the results of their combination in various proportions and under various condirions, the chemist iirrives, not only at their uses and applications, but obtains results before quite unth ought of! Instance the electric telegi'aph. and think how it conveys one's thoughts half roimd the globe before you can express an exclamation of surprise that such things can be I See also the wonderful results of the photographic art, copying the most elaborate picture, machine, or portrait, in a few seconds, and see the results of electro-deposition, which by an invisible agent, coats with pure gold or silver any article subjected to its action, or produces in a mould the article itself of the most elaborate form or pattern, and in solid metal, extracted by this all-powerful agent from liquids which the uninformed woiild never believe could contain any metal at all. Think of the beautiful colours of our carpets, draperies, silks, &c. — the chemist has devised the dyes with which they are stained: and in our chemical factories, what tons of vitriol, soda, bleaching powder, and scores of other chemical agents are daily produced. All this is the result of study and perseverance. Xeither have the Fine Ai'ts been behind in contributing to ci^■ilisation, as may be seen in the structure and decoration of our houses, churches, and public buildings ; in our glass and pottery ware ; paper hangings, and other artistic designs ; in engraA"ing and the copious illustration of our books, sa\-ing a long and tedious description, and often presenting to the eye forms that words could not express. And now let us consider one by one the " materials " and processes from which all these results ai'ise. CO^'TENTS. Xatueal Products : Earths 1 Metals antl Alloys 2 Iron ........ 4 Copper . - 5 Lead 6 Tin 7 Zinc 8 Mercury 9 Gold . . . * 9 Silver 10 Platinum 12 IS'ickel 12 Coal 13 Sidphnr ........ 14 Plaster of Paris ...... 14 Salt 15 Stone 16 AVood 18 Cotton 20 Flax 21 Silk 22 XU COyiEXTS. PAGE jS'atubal Peoducts : India-rubber 23 Grutta-percba ....... 24< "^^ax 25 Kitre 25 Blacklead 26 Spermaceti ....... 26 ^lAyrFACTUEED PeODUCTS : Sugar 27 AJcobol, or Spirit 29 Starch 29 Soap 31 Stearine . 34 Soda 35 ^'ines 36 A'inegar ....... 38 Coal Gas 41 Tar 45 Acetic Acid, or TTood Vinegar . . . . 46 Yarnislies ....... 47 Oils 48 Inks 50 Charcoal . . . . . . . 51 Cements ....... 52 Coke 53 Grunpowder ....... 55 G-un-cotton 56 Phosphorus 56 "WTiite Lead 57 Prussian Blue 58 Pmssiate of Potash 59 CONTENTS. Xlii PAGE Manufactueed Products : Sulphate of Iron 60 Sulphate of Copper 60 Chloride of Lime 60 Sulphuric Acid . . . . . . . 61 Leather .63 Glue and Size 66 Parchment . . . . . .67 Catgut 67 Paper 68 Malt 73 Chocolate and Cocoa 74 Steel 75 Tin-plate, and Gralvauised Iron ... 79 Glass. . " 80 Soda- Water 83 Coal-tar Xaptha 85 "Wood Xaptha, or Pyroxylic Spirit ... 85 PfiODiJCTS OF Skilled Labour: Potterj' 86 Bricks and Tiles 89 Tobacco-pipes . . . . 92 Gold-Leaf 94 Shot 96 Files 98 Type 99 Lucifer-matches 101 Candles 104 Eope 106 "Wire 110 Cutlery 113 XIV CONTENTS. TA.GB Peoducts or Skilled Labour: XaHs 114. Screws 117 Pins lis Xeedles 120 Tubing 122 Steel-pens 123 Akis axd Tkade Peocesses : Wood and Plate Engraving . . . 126 Lithography 129 Printing 130 Photography 133 Bookbinding 140 Paper-staining ...... 143 Flax Manufacture . . . . . . 145 Glass-painting ...... 146 Cotton Manufacture . . . . . 150 "Woollen Manufacture ..... 154 "Weaving ........ 156 Bleaching ....... 159 Calico Printing ....... 161 Dyeing ........ 165 Calendering ....... 167 Bread-making. ...... 168 Sugar Eefining ....... 168 Bre^ving ....... 171 Distillation 174 Gilding ........ 176 Silvering Looking Glasses . . ... 177 Silver Plating 178 Electro-platiug and Deposition of Metals . . 179 CONTENTS. XV PAGB Arts and Trade Processes : Soldering aud Brazing ..... 182 The Smelting of Metals lS4i Founding 185 Glass-blovring and Casting . . . 187 Glass Cutting 192 Bricklaying ....... 193 Stone-cutting ....... 195 Apparatus and !M.iciiinery : Steam Engines ....... 197 Boilers 203 Furnaces 20^! Bellows and Blowing Machines . . . 205 Screw Propdlers 208 Anchors . 210 Chains 212 Cranes ........ 213 Cranks 216 Fire-arms and Projectiles . . .217 Percussion Caps . . . . . . 228 Piunps and Fire Engines .... 232 Valves 234 Wheels 236 "Watermills 240 "Windmills 241 Syphons 242 Stopcocks or Taps 243 Filters 245 Presses ........ 247 Stills 248 Blowpipes . 251 COyiEXTS. ApPAEATUS and MACHiyEET Thermometers . Barometers Pendulums Ploughs . Harrows EoUers . Movring Machines Thrashing Machines Eeaping Machines Drills . 252 255 256 258 259 260 260 261 262 263 EirGiyEEEI>-G "WOEKS : Eailwars . Electric Telegraphs Eoads Bridges Tunnels . Drains Artesian "Wells IMines Ships . Canals and Locks 265 273 282 284 287 289 291 293 295 802 NATURAL PRODUCTS. EMEEALD. GAEXEI. 3. FORTIPICATIOX AGATE. 5. DIAMOND. 4 RUBY. G. ROCK CKYSTAF.. EARTHS. All earths are metala in combination with oxygen: that is to say, they can all be se])arated into a metal and oxy^'eu. The chief earths used are Alumina, found as clay or ylate; Lime, foiind as chalk or limestone ; and Silica, found aa sand, flint, or rock-cr\'stal. These, in various propm-tions, combiuiHl with some few other matters, form, by far, the greatest portion of the earth we dwell on. The earths, when 2 IfATUKAL PRODUCTS. pure, are all white substances, not very heavy, and having scarcely any of the properties of the metals from which they are derived. The next frequent of the earths are Baryta and Strontia; but these may be said to be useless when compared with the three former. Alumina, in its various forms of clay, is used for brick and tile-making, and for pottery; hardened into the form of slate, it is much used for roofing and for making cisterns. Lime, in the form of carbonate, constitutes the best building stones, including marble, so valuable for ornamental carving and decoration, and when burnt, to separate the carbonie acid, forms Hme itself, which is invaluable as a cement Avhen mixed with sand ; lime, in union with another acid (sulphuric) forms plaster of Paris, also a most useful article in the arts, &c. Snica, in the form of sand, is very extensively used for glass making, and, in the form of flint, it is ground and used for pottery : all such stones as quartz, rock-crystal, Scotch pebble, agate, cornelian, &c. are but various forms of Silica, either crystallized or deposited in layers. Most of the precious stones are composed of the earths in a crystal- line state and colored by some foreign ingredient, such are the emerald, ruby, garnet, &c. The diamond is not an earth but composed of pure carbon. METALS AITD ALLOTS. Metals may be known from all other substances by cer- tain properties : they have that peculiar brilliancy, called, for that reason, the " metallic" lustre ; they are rapidly heated, and as rapidly cool, hence they are said to be good conductors of heat ; they are all opaque, and most of them very heavy ; some indeed, as gold and platinum, are the heaviest substances known, being about twenty times heavier than water ; they have, moreover, other valuable properties such as the capability of being melted, of being drawn out into wire, of being beaten into thin plates, &c. All metals are simple bodies ; that is to say, they can- not be made out of other substances, although two or more metals may be combined and be again separated, or they may be combiaed with numerous other substances, as oxygen, &iid also again separated. There are upwards of ^'ATUEAL PRODUCTS. 3 fifty metals known to chemists, yet but few are used to any c.vtent in the arts or manufactures. All the metals in use for the very many purposes to which they are applied are not simple metals, but are what are called "alloys," that is to say, compounds of two or more metals. The chief metala iu use are — lUOTH, MEECtTET, COPPEK, NICKEL, LEAD, GOLD, TIN, BILVEK, ZIXC, PLATINrM, But in the state of oxide many are used which are seldom seen in the metallic state, such are the earths and alkalies; and for colors, and several other purposes, many other preparations are in use. The chief alloys, or compound metals in use, are, brass, made of copper and zinc ; pewter, made of lead and tin; bell metal and gun metal, made of copper and tin; and -solder, which is a kind of pcA^-ter, and made of the same metals ; the silvering for looking-glasses is made of mercury and tin ; the gold and silver used for coin are not pure metals, but alloyed with two parts of silver or copper to every twenty-two of the pure metal, and this forms the " standard" gold or silver. The gold used by jewellers has often a much greater proportion of alloy — for this name is given both to a compound metal and the cheaper metal made to combine with the more precious. The object gained by thus alloying the coinage, is that of ren- dering the metals harder, so that they shall not suffer much loss in wearing ; thus a small quantity of copper mixed with either gold or silver, renders them both harder, although itself softer than either. The combination of certain metals forming alloys, is often not exactly the mean of their re- spective qualities, for instance, a small quantity of silver is sometimes fused with cast steel for penknife blades, and although the silver is itself much softer than the steel, yet the combination is found to be both closer in the grain and harder ; it is kuowai as silver-steel in commerce. Bismuth, although itself not very fusible, increases the fusibility of other metals ; a combination of 2 parts tin, 3 lead, and 5 bismuth, forms a metal fusible by boiling water. B 2 SATITi: OXIDE OF lUOS. IKO>'^. Iron stands first in usefulness of all the metals, for rail- ways, bridges, ships, and a thousand other purposes ; it can be both cast and ■wrought, having that peculiar property, the capability of being " welded," that is to say, of softening while hot to such an extent that when two pieces are made white hot and laid together, a few blows of the hammer will cause them to unite into one piece, and it is by means of this most useful quality' that large masses of "wrought iron are produced, such, for instance, as anchors and cranks for steam-boats. This property of welding, tnd the abmidance of the ores of iron, render it one of the most useful mate- rials supplied by nature for the various purposes of manu- facture. In combination with carbon it forms that hardly less usefiil article known by the name of steel. Cast Iron has scarcely any of the metallic lustre, and is only fitted for solid work ; it is brittle, like steel, without its elasticity', and is too soft and too porous to be made into any of the numerous tools and instruments for which steel is so eminently suitable. Cast iron contains many impuri- ties, the chief of which are carbon, sulphur, and mlica, got from the coke whilst being smelted in contact with it, and from the fliixes used in the process ; it is coarse in grain, and much more fusible than wrought iron, which is iron in >'ATURAL PltODUCTS. n nearly pure state and c^in be fused only by the very liijijliest heat capable of being produced. Cast iron is con- verted into ^v^ought or malleable iron by being re-melted and stirred for a long time in contact Avith the air, this pro- cess is called " puddling," its object is to get rid of all the impurities (chiefly carbon and sulphur) wliich, by being brought into contact with the air at a high temperature, are said to be burnt out, that is to say, they combine with oxygen and form carbonic and sulphurous acids. After ])uddliug, the iron is rolled or hammered out, folded up, and again extended, and as a general rule it may be said, the more this is continued the purer and softer is the iron. COPPEE. NATIVE COPFEE. Copper is a reddish-coloured heavy metal, much used for Fheathing the under part of ships, lor making boilers, &c. It IS about eight-and-a-half times heavier than water, and is too Aaluable to be used for many ])urposcs where cither iron, tinned iron, or zinc are ap])fie^d, but for which purposes its great durability would lit it, *as it is easHy rolled out or >""ATrEAI, PEODFCTS. beaten into plates, and is not quicklv acted on bv the wea- ther. It is used as coin in pence, halfpence, and "farthings ; all vessels for cooking purposes, when made of copper, are tinned inside to prevent the food becoming poisonous from verdigris, which is the rust of copper, and is very injurious. Copper is found chiefly combined with sulphur, forming " native sulphuret of copper." Copper melts at a fiill red heat. ii:ad. srLPHraHT o? lead. Lead is a heavy metal, of a dull blueish tint, and very soft ; it is extensively u^ed for covering roofs, for cisterns, and for pipes for conveying water, as it is easily bent and joined, and is not acted on by the water which passes through it. Lead melts at a heat below that of redness, and, in com- bination with oxygen and carbonic acid, forms the " white lead" of commerce so largely used as a paint. Oxide of lead, called " litharge," enters into the composition of flint glass, and in combination with a larger quantity of oxy- gen forms "red lead," a substance much used in painting. Lead is found in many parts of England, especially Corn- wall, where many lead mines exist ; it is got from the sul- phuret called " galena," which is lead in union with sulphur. What is called ''black-lead" is not lead at all, but is an ore of iron, beins: iron in combijiation with carbon. Lead is about eleven-and-a-half times heavier than water. yATUEAL PEODUCTS, TEN'. Tin is a white metal, almost as white as silver, it is found chiefly in Cornwall. It is a light, soft metal, and, Like lead, is easily melted; it is used chiefly for coating vessels of harder metal, such as iron and copper. It is used to mix witli copper to produce bronze, bell metal, anc' gun metal, and with lead to produce pewter, which used to be so extensively used as table-ware before the manufacture of earthenware became general for that purpose. Tin does OXIDE OP TIX not easily tarnish or rust by exposure to the air, hence the use of tinned iron-plate. Tin, united with merciiry, forms the silvering for looking-glasses. Tin is about seven-and-a- half times heavier than water. ZI>'C. Until the last quarter of a century, zinc was but little used, but of late it has taken the place for many useful pur- poses where lead was formerly used, principally owing to its cheapness and lightness. Zinc is a hard metal of a grayish colour, not easily bent but rather brittle, but when made 8 >'ATrEAL PEODTJCTS. nearly red hot, it is capable both of being rolled out into sheets and being beaten into form by the hammer. Zinc is about six-and-three-quarter times heavier than water. Like many other metals, zinc is volatile, that is to say, when heated to a certain extent it passes off into vapour, and there is no doubt, the reason that zinc was not kno'mi or used of old was that it was chiefly lost in " smelting," or getting it from its ores. Zinc is now obtained by a sort of distillation ; the ores are mixed -R-ith the flux, &c., in a large earthen crucible or pot, from which an iron tube passes into a vessel of water, the lid is securely fastened on, and as the heat is urged the zinc is driven off" in vapour, passes down the tube and condenses in the water. The zinc of STJXPHTJKET OP ZIXC commerce is obtained chiefly from the ore known by the name of " calamine stone," which is zinc in combination with oxygen and carbonic acid. A substance called " zinc white" has been lately introduced as a substitute for white lead, and would certairdy supersede it, but the zinc is found to be deficient in " body," which means, the power of cover- ing anything over which it is laid-on in a thin layer, but as zinc white does not blacken in foul air, and white' lead does, it has a great advantage, and it is to be hoped that some improvement in its manufacture may improve its "body." Zinc is chiefly used for roofs, gutters, water-pipes, cisterns, and various vessels for holding water, as it does not rust so easily as iron. AVliat is called '• galvanised iron," is iron dipped into melted Zinc in the same way that tin-plate is. yATUBAL PRODUCTS. MEECUEY. Mercury, or quicksilver, is known from all other metals by being fluid at the ordinary temperatvire of the air. This is only oAving to its extreme fusibility, for at 72 degrees below the freezing point of water, it also becomes solid, and may be hammered out or cut by a knife ; it is very hea\y, being about fifteen-and-a-half times that of water, so that most of the metals will float on its siu-face ; it has a bright lustre and is almost as white as silver. It is found both in the fluid metallic state, and in combination with sulphur, in which last state it is called '"cinnabar;" this is a heavy mass of a deep red color, and when ground to powder, of a most magnificent red, and is the vermillion so well known as a pigment ; this vermillion is, however, most frequently manu- factured by combining the mercurj' and sulphur, both first purified, in this way a more brilliant color is produced than can be got from the cinnabar. The metal is extracted by heating the cinnabar with iron-filings or Kme in a retort, by which means the mercury distils over and the sulphur is Ipft behind united ■with the iron or lime. Mercury is used for many purposes in the arts and sciences, for barometers, thermometers, compensating pendulums for clocks, &c., and also in the processes of water-gilding, look- ing glass silvering, and in tlie Daguerreotype process. The combinations of mercury with other metals are called " amalgams." GOLD. Gold is the heaviest of the metals with the exception of Platinum, being rather more than nineteen times heaner than water ; it is of a bright yellow color, and is not tar- nished by exposiLre to the air or moisture, hence its useful- ness in ornamenting frames, cornices, &c., Gold is chiefly used, in the form of coin, as the medivun of exchange ; for ornamental purposes, such as jewellery ; for gilding, and for staining glass, to which it gives a bcautifid ruby-red color. Gold coin contains about one twelfth part, by weight, of copper, this is added to give it hardness and consequently cause it to lose less by wear in use. Gold is not dissolved 10 ^TATrEAL PE0DrCT3. by any of the pure acids, but a mixture of hydrocliloric and liitric acids will dissolve it in consequence of giving out chlorine, an element -which freely dissolves gold. Grold is capable of being beaten out into leaves of extreme thinness, and also of being dravm into wire of such thinness that five hundred feet of it weigh but one grain. SILTEE. Silver is the whitest of the metals ; it is about ten-and-a- half times heavier than water ; it does not easily tarnish by the air, and is not converted into dross by heat continued for any length of time, or, in chemical language, it is not oxydised ; it is chiefly u^ed for coin and for ornamental pur- poses where its cleanliness and beauty are strong qualities to recommend it. Many kinds of lead ore contain silver, and when this is in sufficiently large proportion to pay for its extraction, the reduced lead is subjected to the flame of a furnace which is blown on to it with a strong blast, the flame melts the lead and converts it into an oxide called "litharge," which is in the form of reddish scales, and as these are formed the blast blows them oflT; in this way the lead, is gradually consumed, leaving the silver with but a small quantity of lead, this is put on to a cup made of bone NATURAL PHODUCTS. 11 aslies called a "cupel," hence this operation is called "cupel- latiou," the heat is then raised, and the lead which remains with the silver, forming a liquid glass with the bone ashes, sinks into them, leaving the silver bright and pure. Silver in some districts is extracted from its ores by what is called " amalgamation ;" the finely powdered ore is mixed with water, some cuttings of iron and quicksilver, and turned round in a barrel for a considerable time, when the quick- silver is draAvn off through a small hole, and is found to con- tain aU the silver in the ore, together with some other metals. The quicksilver is got rid of, first by pressing and then by distillation ; so that it is all recovered for a second operation. What remains is separated from the other metals, which it may have been mixed with by diflferent processes, according to the nature of these metals. The standard silver of the Mint is what is called 22 carats fine (nearly), that is to say, 22 parts in 24, the two parts being copper ; this is done to harden it. The silvering of looking-glasses is made of a compound of tin and mercury, but a process for really silvering looking-glasses has been patented by Mr. Drayton ; it consists of precipitating silver from its solution by means of the oil of Cassia, or some other ]2 >'ATUIIAL PEODUCTg. volatile oil : tlie process is far too expensive for general use or for large plates. Silver leaf is made and used in the same way that gold leaf is. PLATINUM. Platinum is a metal of a white color, and is the heaviest substance kno"mi, being more than twenty-one times heavier than water. It is capable of being welded and wrought out by the hammer like iron ; it is not acted on by any of the acids, but, like Gold, is dissolved by chlorine or a mixture of hydrochloric and nitric acid ; it does not tarnish by expo- sure to air, and is extremely difficult to melt, requiring the very highest heat that can be produced; these qualities render it one of the most useful of the metals to the che- mist, furnishing him with retorts, crucibles, and evaporating dishes suitable for many purposes ; its high price, however, renders it not so generally used as it would otherwise be. KICKEL. This metal is of a white color and very difficult to melt, it is about eight times heavier than water and is chiefly obtained from the ore known as kupfer-nickel, found very plenti- fully in Grermany ; this kupfer-nickel is a native arseniuret of nickel, that is, nickel in chemical combination with arsenic. It is very difficult to separate these two metals, but an eff'ec- tual and cheap process lias lately been devised to do so. Nickel is attracted by the magnet similar to iron but in an inferior degree. Till lately nickel was but little used, but it now forms the basis of those compound metals known as nickel-silver, Grerman-silver, and British-plate, all which varieties are generally employed as an economical sub- stitute for silver ; it is also used largely as a foundation on which to deposit pure silver by the electro-plating pro- cess, for which purpose it is most admirably suited being very superior to copper in consequence of its color, as the silver always wears off unequally and exposes the ground work of metal beneath. Grerman silver is composed of cop- per, nickel, and zinc, ia various proportions. Nickel always forms one of the constituents of meteoric iron, those myste- rious masses called aerolites, wluch sometimes fall to the earth. M I >• E R A L S. COAL. This, the richest product of the mine, the ■well-know a fuel used in almost every branch of industry as well as for warming ovir houses, is got from the depths of the earth, where it exists in certain localities forming what are called " coal fields" or "basins." It is the residt of changes pro- duced during many ages upon vegetable matter buried during the various convulsions which the earth has under- gone, aud pressed into layers or strata of various thicknesses. To raise this valuable fuel, poAverful machinery is used and deep shafts are sunk at an enormous expense. Coal exists in various forms : the following are the most easily recognised : — 1. — Cubical coal ; shining and easily broken into squarish fragments. It bums brightly. 2. — Slate coal ; dull in color, splits like slate. Bums well. 3. — Cannel coal ; dull color, breaks like resin, and some- what resembles jet. Bums brilliantly, and splits with a crackling noise when in the fire. It atibrds the best gas. 14 XATUEAL PEODT'CTS. 4. — Glance, or Kilkenny coal; steel-grey color and metal- lic lustre. Burns without flame or smoke, somewhat Hke charcoal. 5. — Lignite, or brown coal; is an imperfectly formed coal. The quantity of coal used is rapidly increasing owing to the extensive number of steam engines used, especially for navigation and railway transit ; and it is a problem, not yet determined, how long the coal existing in Great Britain is likely to last ; the lowest statements make it but little below a thousand years. SULPHUE. Sulphur, also called Brimstone, is a natural production, and is found either pure, or combined with metals forming ores, for the most part called " pyrites," as, iron pyrites, copper pyrites. &c. In chemical language these compounds are called " sulphui'ets" or '• sulphides." Sulphur is one of the elements; that is to say, it is a simple body, or one neither capable of being made nor separated into other ingredients. It is crystalline, of a bright yellow color, very inflammable and volatile, bums with a blue flame and gives off" pungent fimies of sulphrous acid. It is got pure by distillation from various substances containing it, and in Sicily is found nearly p\ire as a volcanic product. Sulphur is chiefly used for the manufacture of sidphuric acid and gunpowder, and was also largely used for making matches, but phosphorus (a still more inflammable subtance) has almost superseded it in the manufacture of this necessary article. PLASTEK OP PAEIS, OE GTPSril. Plaster of Paris is sulphate of lime — a combination of lime and sulphuric acid ; and exists abundantly in various degrees of purity ; it occurs plentifully in the locality of Paris, and is brought here in masses of a greenish, pink, or brown color. To prepare the g^-psum it is first made red hot, to separate the water which it contains, and then ground to powder of various degrees of fineness. Plaster of Paris has the peculiar property of uniting with a certain quantity of water and forming a solid compoiind with it ; upon this property all its usefulness depends. If a portion of Plaster NATURAL PEODUCTS. J 5 of Paris be mixed with sufficient water to form a liquid of the consistence of cream, in a few minutes it will harden and become quite set, and as it dries, it will harden still more, till it is of a hardness almost equal to stone : tliis useful property causes it to be much used for casting figures and ornaments ; cheap plaster figures, &c., are generally cast hollow, to save the plaster; this is done by pouring into the mould a certain quantity of the plaster mixed with water, and quickly turning the mould about so that it shall adhere and form a layer on all the inside of the mould ; when set hard, the mould is taken to pieces and the figure finished by scraping ofi" the marks where the mould was joined. Plaster of Paris, combined with whiting, forms what is called by plasterers " putty," and is much used for ceilings, and similar purposes. SALT. Salt is one of the most widely spread and plentiful minerals which the earth gives for the use of man ; all the water of the ocean derives its saline taste from salt ; many springs are completely saturated and are hence called "brine springs," and it also exists crystallized in beds within the earth of im- mense thickness and extending for miles each way. The salt mines of Cheshire are the fijiest and most extensive in England, and in some places the stratum or layer of salt is more than one himdred feet thick, perfectly white and crystal- lized. Salt is not a simple body, but is composed of two simple bodies or elements, chlorine and sodium, hence it is called by chemists the chloride of sodium, it can be formed by put- ting carbonate of soda into hydro-chloric acid (sometimes called muriatic acid,) until no more efiervescence takes place, tlie result will taste salt and yield pure salt on evaporation. The waters of the sea are in some places evaporated by the heat of the sun in shallow hollows dug out in the beach, this is called "bay salt" and is very impure; but the chief part of the salt of commerce is procured by evaporating the waters of brine springs ; this water is pumped up into large iron cisterns placed beneath sliglit sheds to keep the rain oil", and having flues running beneath them, the first impuritcs are thrown away, aud as evaporation goes on, the salt cr} f^tallizea 1(5 ^ATrEAL PEODrCTS. and falls to the bottom of the cist-em in a fine white powder ; this is taken out with wooden shovels and placed in conical vessels with a hole in their lower part to drain off all the moisture ; it is then dined by stoves and is fit for use ; when no more salt falls down, the impure liquor, called '•bittern," is draAvn ofl" and used to procure Epsom salts from, by mixing it with sulphuric acid. The bittern contains chloride of magnesium, and the sulphuric acid changes it into sulphate of magnesia, which, when purified, forms the Epsom salts sold by druggists. About half a million tons of salt are made in England every year. Salt, besides its general use as a condiment, and in preser^-ing food for storing ships, &c., is also used for several manuiacturing purposes. By adding sulphuric acid and heating it, the acid called "hydrochloric" is given ofi", which is largely used for many purposes ; but the chief use made of salt by the manufacturing chemist is to prepare soda for cleansing and soap making. STO>'E. Stone for building is chiefly of four kinds : — Ume-stone, eand-stone, granite, and marble. Slate is never used for building, but is very suitable for roofing. The most com- mon stone is limestone, and that brought from Portland Island is especially good for budding-stone ; it is caUed Portland stone, and it is of this stone that St. Paul's Cathe- dral is built, and most of the other public buildings of London : it is rather soft when first dug from the quarry, but hardens with age. Sandstone is a very coarse kind of stone, and is only used where not much exposed to the wea- ther ; it consists of grains of sand adhering so firmly together as to form a stone of considerable hardness. Granite is a very hard stone, and very durable ; so hard that it cannot well be cars'ed. and is therefore only used where durabdity and plain soHdity are required ; London Bridge and the Euston Square Terminus of the Birmingham Kailwav are buUt of granite. Marble is a very fine heavy kind of lime- stone, sometimes qvute white, and generally partly trans- parent ; the white kind is very expensive, and is used for statuary, that is to say, for carving into figures, vases, &c. ; STONE QUARRY. it is very durable, but is too expensive for general use. Cliimnev-pieces, slabs for Avashing-stauds, and other articles of that description, are also made of it. Limestone, marble, and also chalk (a soft kind of lime- stone), all become changed into lime if made red hot, lience the name, limestone, is often applied to all three. Stone quarries are those places where stone exists of a (jiiality suitable for building purposes, and in a situation admitting of its easy removal. All stone, with tlie excep- tion of granite and marble, exists in layers or strata as they are called, so that the stone can be easily split in the direc- tion of these strata or seams. "When a large piece of stone has to be removed, wedges are driven in a row into these seams, and when the stone has started, it is notched at the sides and back, so that in general a square piece is thus removed ; if it be not so, it is generally made into a some- wliat square before leaving the quarry, hence the name, derived from the French "quari-e." Granite liaving none of tlie lines of cleavage, as tliey are called, is broken c IS XATrT?AL PRODFCTS. by a roAv of wedges dvhen till a crack forms from one to the other. Slate is a clay -stone found in layers like lime- stone, bnt much more perfect ; so much so, indeed, that it can be split into slices a qiiarter of an inch thick and one or two feet square ; these, when sorted into sizes, form tlie slates for rooting houses. It has been much iised of late in thick slabs, cut by circular saws, for making cisterns, a piirpose for which it is well adapted. WOOD. "Wood is an article of universal application ; its lightness, strength, and the facility with which it can be woi-ked. render it almost invaluable ; although in ship-building and many of its applications to house-building iron has to some extent superseded it, yet there are so many other ways in which it is indispensable, that it may be looked K^ATURAL PRODrCTS. 19 upon as one of tlie greatest boons to mankind. There is scarcely a use to which wood may not be applied, whether SLA fuel for fires, timber for building, furnitui'e both useful and ornamental, various parts of machinery, vessels to con- tain wine and other fluids, handles to instruments, (for in cx)ld climates and cold weather metal cannot be handled with impunity), and indeed for all uses in which lightness, dry- ness, warmth, and variety of form are desirable, wood serves as an excellent material. The kind of trees that produce wood fit for building and other useful purposes are those called by the botanists exogenous. Amongst which the pine tribe, oak, ash, elm, and beech, stand pre-eminent; while mahogany, walnut, and rosewood are chiefly used for ornamental purposes ; box-tree wood is also very useful on account of its closeness and evenness of gram ; it is the wood used by engravers. "Wood when first cut is wet and heavy, but, by being exposed to the air, it shrinks and the sap dines up in it, it is therefore liable to swell and become damp in moist situations this is detrimental to its usefulness; most woods therefore are improved by being soaked a long time in water, this cleanses it from saline and extractive matters which keeps the wood damp, but which, when separated, allow tlie wood to shrink and harden permanently, this process is called sea^ soning, the same efl'ect may be produced by exposure to the air and rain, it is generally resorted to when the timber is cut up into smaller pieces. The structure of wood is porous, hence its lightness, it has also a grain which runs the whole length of the wood in circles round its centre to the surface, one of these circles is produced every year while the tree is growing ; wood is therefore capable of being cleft in tlie direction of the grain by a wedge, in this way builder's laths are made. Wood cannot be cleft across the grain,^ but must be cut by sawing or other\\'ise. The pine or fir tribe produce the largest and straightest timber, but it is not so strong nor so durable as oak and many other woods. Some specimens of the Araucaria J£xceha or Norfolk Island pine, have stems upwards of tliree hundred feet high, and in the Crystal Palace is the bark of another gigantic tree the Wellingtonia Gigantea. c 2 COTTON. Cotton consists of the fine long hairs which grow from the seeds of several varieties of Gossypium, a plant belong- ing to the natural order of Malvaceae. These hairs are so long and nmnerous that they completely fill the pod or seed vessel ; they are very delicate, and of the same size through- out, and but seldom jointed, they are each separate from the other. The cotton plant is chiefly cultivated in America and India. In India, and some of the islands in the Indian Ocean, cotton has been cultivated, spun, and woven into textures from time immemorial. Cotton fabrics were in use in Mexico before its conquest by the Spardards, and have been used in China for many hundred years; its chief source now is America, where more than two hundred times the quantity is gro^\^l at present than was grown there half-a- century ago; but the internal communication brought about NATUEAL PRODUCTS. 21 by railways in India, may, in all probability, revive the cul- tivation of cotton in that country ; the cost of conveyance from the interior having been one of the greatest drawbacks to its exportation. Cotton is not only cheaper than linen (which is woven from flax), but has several advantages over it : it takes dyes much better, and produces brighter colors ; the improve- ments made in the machinery for spinning and weaving cot- ton, have not only enabled us to match the spinners and weavers of India, which, for a long time supplied nearly the whole of Europe, but at the present time, cotton cloths of English manufacture are exported to India for the purpose of clothinff the natives of that country. FLAX. Flax is obtained from the stalks of the flax plant LInun Usitatissimum, it is supposed to have been originally brought 22 yATUEAL PEODrCTS. from Egypt, where linens have been woven from its fibres from time immemoriaL It is now found growing wild in this country, and is eidtivated in most parts of Europe, either for its stalks to make flax, or for its seed (linseed), which is used for fattening cattle, and yields an oil (linseed oil) much used in the making of paint. The plant grows to two or three feet in height, bears a blue flower in July, and has a great hollow stem ; when gathered, it is pulled up by the roots. The fibres of flax are very long and even ; it is the inner part which yields the best fibres. STLK. Silk is by far the strongest of the textile fabrics, being nearly three times as strong as flax ; it consists of the fila- ments spun by the silk-worm, Phaloena JBomhyx Anori. These filaments are always double, proceeding from two holes in the head of the worm, and are united by a sort of varnish which is moist and clammy when the threads pro- ceed from the insect, and causes them to adhere together. The silk-worm in spinning, moves the head backwards and XATFRAL PRODUCTS. 23 forwards, attaching the threads on alternate sides and all around till it is completely covered in with a ball of silk ; in this state it is called a " coccoon." The silk-vrorm, like others of its class, xmdcrgoes four changes or metamor- phoses — the Egg, the Grub or "Worm, the Chrysalis, and the Imago or perfect insect, which, in this case, is a moth. The worm spins the coccoon to defend itself from injury and cold, but man, taking advantage of the useful qualities pos- sessed by these fine tiJaments, spins them into his most gor- geous apparel. The coccoons are unwound by placing them in a basin of warm water, which dissolves the varnish, and they are then slowly wound ofl' ; formerly this was done by hand, but now machinery is chiefly employed which winds oft' the silk from a bowl full of coccoons at the same time. The silk is coiled into hanks or skeins, and in this form is imported into this country ; from these hanks it is wound off on to large six-sided wheels called " swifts," and from these on to boddins or reels ; it is then wound oft' from two or three of these bobbins on to one other bobbin, the tlu-eads of silk being laid side by side, and in this process a t\vist is given to it in one direction and two of these wound on to another recei^nng a twist in an opposite direction, this forms a fine cord called " organzine," which is used by the silk weaver in the same way that yam is by the cotton weaver. The short and broken pieces are carded and spun like cotton, and is called floss silk. The raw silk is of a bright buff or golden yellow color, but there are some kinds which are white. rS-DIA-BrBBEE. India-rubber or Caoutchouc which was, a short time back, used only for the very insignificant purpose of rubbing out pencil marks, is now used for almost innumerable piirposes. India-rubber is the solidified juice of several trees, such as the Siphonia, Jatropha Elastica, Ficus EJastico, &c., the juice is got by making incisions in the trunk of the trees during \vinter and collecting the juice, which is caoutchouc com- bined with water, in the fom\ of a milky thick fluid, the water is then allowed to evaporate and the India-rubber remains. It is brought here in all sorts of shapes, and ' 24 KATUKAL PEODrCTS. is purified before it is fit for commercial use by washing ia warm water or steaming ; it is then cut into pieces and put into a kneading machine which cuts and works it together with such rapidity that it becomes quite hot and the pieces join into one mass. After having undergone every kind of torture that can be well imagined in the form of cutting, tearing, and squeezing, it is finally compressed in a square cast iron mould, where it is kept for a time, and then is tit for anv use it has to be applied to. "VSTiat is called vul- canized India-rubber is produced by incorporating it with powdered sulphur, or some substance containing it, as sul- phuret of antimony, or the vapour of sulphur is kneaded into the mass ; this vulcanized rubber is very elastic and does not harden by cold. "Waterproof fabrics are made by stretching the stufi' to be waterproofed on a frame, at one end of which is a partition having a sHt in- it, through which it is drawn, after haWng been smeared with a solution of India-rubber in naptha ; the slit is so narrow that it scrapes ofi" all superfluous caoutchouc, it is then dried in the air. GUTTA-PEECHA. Gutta-percha is a substance possessing many useful and valuable propei-ties ; it was unknown in Europe until within a very recent date, though it is said to have been in com- mon use, for a long period previous to oirr discovery of its utility, amongst the natives of the Indian Archipelago, chiefly for making axe-handles. It is the concrete juice of a large tree, supposed to be the Isonandra Gutta, and is brought to Europe in irregular masses of a brown color, and contains various impurities which are easOy got rid of by working it in hot water. Gutta-percha possesses the desirable pro- perties of being soKd, slightly elastic, not brittle, and very tough, capable of being melted at the heat of boiling water, and being drawn out or moulded into almost any form ; it resists the action of water and spii-its, unless verj- strong, oils, alkaHes, and weak acids, but spirits of turpen- tine, chloroform, and naptha, each dissolve it. A substance which has so many valuable properties as these, of coiirse enters into a multiplicity of forms and uses. KATTRAL PRODUCTS 25 NVAX. This useful substance is produced by bees for tlie pur- pose of building their comb, which consists of hexagonal cells made of wax ; which substance they secrete in scales, between the sections of the abdomen, and draw out for building their beautiful cells. WTien the honey is drained off from the comb, this is washed and melted, it then constitutes the yellow wax of commerce, commonly called " bee's-wax." To make this into the white wax it is boded in water, spread out into thin layers, and exposed to the light and air ; this is repeated until all the color has gone and the wax remains pure and white. Pure wax is a soft- feeling substance, harder than tallow, and not greasy to the touch ; it is easily melted, and burns with a clear white flame, hence its most general use — namely, that of making candles ; it is not soluble in water, but unites with oils and fats. NITRE. This substance, known also in commerce by the name of saltpetre, is brought to this country from India, where in certain places, it forms a sort of efflorescence on the sod ; this is taken oft' together with the surface of the soU, and mixed with water, which, after all the earth has sub- .^^ided holds the nitre in solution. The water is then evaporated and the nitre crystallizes in six sided prisms. On most parts of the continent nitre is manufactured from what are called nitre beds, these consist of old mortar and other matters containing lime, as the dry rubbish from old building, &c., together Avith manure and other animal refuse. These beds are packed up and kept from the rain for a certain time, when a small part of the lime is found to be converted into nitrate of lime, this is the white sub- stance frequently seen to exude from newly built walls in the form of crystals like snow. The whole mass of the nitre bed is next washed ; the water used for the first por- tions being poured over the next, and so on till it is pretty rich in nitrate of lime, this is then mixed Avith carbonate of potash, which decomposes the nitrate of lime forming 2G VAXrEAL PEODrCTS. nitrate of potash, (nitre), and carbonate of lime, (chalk) ; this last settles down and leaves the solution of nitre clear, ■which is evaporated, and the nitre got pure. Xitre is used for making gunpowder and fireworks of difierent kinds, also for curing meat, especially pork and beef, to which it imparts a red color ; it is also used for making nitric acid, in the manufacture of sulphuric acid, and as a medicine. BLACKLEAD. This substance, called by mineralogists " plumbago" and " graphite," is found in small quantities in various districts, and in a very pure state in Cumberland. It is almost pure carbon, having but a very slight admixture of iron ; it is used to make blacklead pencils ; for coating the surface of iron, giving it a bright appearance and preventing it from rusting: it is also used to prevent friction in wooden machinery, and, mixed with tallow, as a lubricate for iron machinery; black- lead, mixed viith clay, is also used to make crucibles for various purposes, these are especially adapted for melting glasses and enamels, and are known in the trade as blue pots. SPEEMACETI. This substance is obtained from the oily matter contained in the head of the spermaceti whale, Phyceter Macrocephales, which consists of sperm oil and spermaceti. The latter crystallizes as the mass cools, and is afterwards purified. It is white and crystalline, is used chiefly for candles, or mixed with oil and Avax. it forms an ointment. :»IAXUFACTURED PRODUCTS. SUGAR. Sugar, like starch, exists naturally formed in many vege- tables, and has to be separated from the various foreign matters A^ath which it is combined ; the sugar used in this country is all extracted from the juice of the sugar-cane, Arundo Saccharifera, but in France a great portion la extracted from beet-rout. 2S MA>-UrACTrEED PEODrCTS. The raw, or Muscovado sugar as it is called, is a browrush compourid of small crystals of sugar held together b j molasses or treacle, which gives the sugar its color and peculiar moist- ness ; when pure, sugar is quite white and capable of crys- tallization, as may be seen in sugar candy, whichis crystallized sugar ; sugar, if heated, becomes converted into a dark brown liquid called burnt sugar or " caramel," this has an intensely rich color, but scarcely any sweetness ; it is used to color wines and spirits. The tendency of sugar to be converted into caramel is very great, and the whole difficulty of sugar refining depends upon this fact, for a solution of sugar heated is constantly changing into this substance. To obtain the sugar from the sugar cane, it is first crushed between powerful rollers, by which all the juice is pressed out, this is immediately clarified by boiling it strongly with a small quantity of slaked lime, or it would speedily ferment, it is then put into evaporating pans, in which it is evaporated till it is ready to crystallize or granulate ; from these pans it is ladled out into a cooler, and from thence into wooden boxes where it granulates; the next process is called "curing" this consists of draining the sugar of its molasses, for this purpose hogsheads or large broad barrels are arranged on a sloping floor, and ha\'ing several holes at their lower part with a piece of plantain leaf put into them ; through these holes the molasses runs out and is collected in a vessel for the purpose. The best kinds of sugar are partly purified by a process called " claying ;" this consists in putting the sugar into conical earthem jars, "nith a hole at the point which is turned downwards ; the top is piled up with a mass of wet clay, the moisture from which slowly sinks do'wn, carrying with it most of the coloring matter of the sugar ; the cone of sugar is afterwards dried, broken up, and each part ground up separately, as they form sugars of different value, the point being the bro^vnest and the base of the cone the whitest. Sugar is made from the beet root in the same way as from the cane, the roots being rasped up into a ptdp by a wheel with a notched edge acting against them. Beet-root sugar crystallizes better than cane sugar ; otherwise it is exactly like it, and purifies as well. MANUFACTUEED PB0DUCT3. 29 ALCOHOL, OE SPIEIT. Alcohol, commonly called spirits of wine, is procured from any liquid which has undergone the vinous fermenta- tion, such as wine and beer. The spirit used in England is procured from a wash made by pouring boiling water upon ground malt, as for making beer ; this, when fermented and distilled, produces a colorless spirit, which, by being again distilled at a gentle heat, called rectifying, produces a very strong spirit ; but even this contains some con- siderable quantity of water, and to get rid of this, for cer- tain chemical purposes, it is necessary to add carbonate of potash, quick lime, or some other ingredient greedy of water, and again distil it. Brandy, mm, and whiskey, are but various forms of spirit colored and flavored with different substances. Brandy is distilled from wine ; rum from the molasses, a sort of treacle produced in sugar making ; and whiskey from malt. The strongest brandy does not con- tain more than one half of its bulk of pure spirit. Alcohol, when pure, is a very limpid, colorless fluid, lighter than water, in the proportion that 792 bears to 1000. It is very volatile, boiling at 172 deg. of Fahren- heit, and highly inflammable, it dissolves resins and volatile oils, aud is, therefore, used largely in perfumery. The well known lavender water and eau de Cologne, are solutions of volatile oils of various kinds in pretty strong alcohol, and what are called spirit-varnishes, are most of them solutions of various kinds of resin in strong alcohol, although some of them, as mastic varnish, are made with spirit of turpentine, a volatile oil, in place of alcohol. STABCn. Starch exists naturally in various kinds of grain, as wheat and barley, and in the roots and tubers of many plants, as potatoes. The process of extracting the starch, and sepa- rating it from the other constituents of tlie seed or root, consists, essentially, of crushing it, and wishing out the starch ^^•ith cold water ; the liquid resulting from this mode of treatment is of a milky whiteness, and deposits starch by 30 MANUFACTUEED PE0DUCT8. sediment. This liquid is passed through five sieves to sepa- rate the husks and skins, and when the starch has settled, and the liquid fermented and become sour, it is dravni off ; it is allowed to become sour as the gluten of the grain is more completely separated by so doing. The starch is repeatedly stirred, allowed to settle, and the water drawn ofl", till it is quite pure ; the top of the starch is scraped to separate any slime adhering, and the pure starch dug out with wooden shovels and put in a box lined with linen, in which the moisture drains off ; the cakes taken from these boxes are cut up into squares, put upon bricks, and dried by a gentle heat ; the squares are then scraped clean and packed in paper for sale, in these packages it breaks up into pieces, so that when they are opened, the starch has that peculiar appearance so familiar, and almost resembling six-sided columns. Arrow-root is the starch obtained from ^a West Indian plant called Maranta Arundinacea. Cassava and Tapioca are starches from the manioc, and Sago, from the sago palm. Starch, under the microscope, appears in the form of minute globules, and is quite insolu- ble in cold water, in which it falls to the bottom, leaving the water at the upper part quite clear ; but water that is nearly boiling (that is to say at 160 deg. of Fahrenheit's thermometer, or above), breaks or dissolves the granules, and the starch forms with it a sort of paste, this is the liquid used for stiffening linen and other articles in domestic laundry. The starch sold in this country is colored blueish by smalt or indigo ; but on the continent is used of its natural white color. If starch be baked in an oven at the tempera- ture of about 300 deg. it becomes, to a great extent, soluble in cold water, forming what is called " British gum," this is largely used for calico printing and other purposes ; if boiled in water under great pressure, so that the temperature can be raised to the same degree, it is also changed into an adhesive sort of gum — this is the substance made use of by the government authorities to spread over the backs of postage and I'eceipt stamps to make them adhere. The starch of grain during germination, or growth, becomes converted into sugar ; the same effect can be produced by heating starch with diluted sulphuric acid. SOAP. This very useful article is produced by a combiuation of tallow or oil with soda or potash ; with soda, hard soap is formed ; with potash, soft soap. The yellow soap of com- merce has also an addition of resin or turpentine, and often palm oil, these give it its yellow color and peculiar smeU ; pure white soap is made by boiling a solution of soda with tallow or oUve oil ; ordinary soaps are generally made by mixing a solution of the soda of commerce, (carbonate of soda) with quick lime, this takes away the carbonic acid and makes the soda what is called "caustic;" this solution is drawn oti", and kitchen stuff, tallow, turpentine, and some- times palm oil, are added and boiled together, until all is converted into soap, but a large quantity of water remaining, it is necessary to separate the soap from this, for this pur- pose salt is added until the wati^r becomes so heavy that the soap rises to the surface, whence it is removed into moulds or frames and allowed to cool, when it is cut into bars for sale. 32 MAXTJFACTUEED PRODFCTS. Soft soap is made in the same way, using potash instead of soda, and, generally, a large quantity of train-oil. Castile CITTTIXG SOAP. soap is pure soda soap, and the blueish or red mottled appearance is produced by stirring in some sulphate of iron (green A-itriol) ; when new it is of a blueish color, but gets red by exposure to the air. COPPEES FOE THE MIXISG PEOCESS. Oil? and fats combine with the oxides of several of the metals, and a combination of oxide of lead with olive oil forms a firm solid substance, or plaister, which, with the MAKUFACTURED PRODUCTS. 33 addition of" a little resin, is used in surgery, and when spread upon linen or calico, forms the common adhesive plaister. VILLING YELLOW SOAP. Oils and fats all consist of a combination of organic acids, (stearic, oleic, and margaric), w-ith glycerine. When these lilts are boiled with soda, potash, or metallic oxides, a com- MOTTLED SOAP PEAME8. biuation of the oxide and fatty acid takes place, and this constitutes soap. The glycerine is then set free, and, when purified, forms a sweet, oily, colorless fluid, very similar to svru[), but not so sweet ; it has lately been used for several purposes, especially as a remedy for chapped hands ; a soap 34 :MJorurACiuiiED PEODrcTS. called " glycerine soap," has lately been used for the same purpose ; it is a soap made without separating the glycerine. MACHIXE FOE CrXTIXG SOAP IS BAE3. The above illustration represents an ingenious contrivance for the purpose of cutting soap, STEAEI2rE. The Stearine Candles, so much in use of late, are made of what chenusts call "stearic acid." It is extracted from taUow by the following process : — The fat is first melted, then boiled with Avater and quick Lime : the lime forms a solid insoluble soap with the stearic acid of the fat. This, when cold, is dug out of the cistern and separated from the waterv parts : it is then melted in a wooden cistern by means of perforated iron pipes, through which steam passes ; the steam not only melts it, but condenses and runs to the bottom, thoroughly washing it ; it is again allowed to cool, separated when it is mixed, stirred well ■«"ith sulphuric acid and a large quantity of water, and allowed to settle. This separates" all the lime, which settles to the bottom, leaving the stearine floating on the top, from whence, when cold, it is taken and again well washed with steam. The mass, after cooling, is cut into shavings by a machine consisting of a wheel, having knives attached to its edge ; the shavings are put into hair-cloth bags and subjected to the most power- ful pressure by means of the hydraulic press ; each hair- MATfUFACTURED PEODUCTS. 35 cloth bag having a warm iron plate interposed between it and the next bag. The oilv parts of the mass are, by these means, all pressed out ; the remainder is again cut up and a second time pressed, leaving the pure stearine, white and crystalline like spermaceti. SODA. The Soda of commerce is a carbonate of soda, and it is made from sea salt. It is used in large quantities for the general purposes of washing and cleansing, and very extensively in bleaching and soap making. Soda occurs in two forms — soda ash and in crystals ; the first is the crude soda before crystallif ation. To make soda, oil of vitriol (sulphuiic acid) is poured, by degrees, on a layer of sea salt, in a sort of fun- nel connected with a tall chimney ; on the addition of the A"itriol, copious fumes of the hydrochloric acid are given off; this is the acid formerly called spirit of salt. "WTien the fur- nace is heated and all the acid driven off, the dried residue is taken out, it is sulphate of soda. It was formerly the custom to allow the hydrochloric acid to pass up a ven- tall D 2 36 MAyrFACIUEED PEODrCTS. chiiimey so tliat it may be dispersed in the air ; but sucli an injurious effect was produced on tbe surrounding vegetation that this could no longer be allowed ; the plan adopted was, to cause the acid to be condensed by filling the chimney ■\\-ith coke, and causing water to trickle through it ; the acid vapours, coming into contact with this porous wet surface, is condensed into a liquid, which runs down into a cistern placed to receive it. The sulphate of soda, when taken from the furnace and cooled, is next ground in a mill with rather more than its weight of chalk, and about half" its weight of coal. This mixture is placed in a furnace and raised to a sufficient heat to partly fuse it, during which time it is stirred about : the black mass which residts is called by the woi'kmen " black ball." It is taken out and put into a cistern ; water is then poured over it, and after stirring, it is di'ained off" and evaporated to a dry mass ; this is impure soda. It is mixed with coal-dust, again burnt, again washed and evaporated, by this second process the soda ash is produced, which, being dissolved, filtered and evaporated, produces large crystals of soda. The large quantity of hydrochloric acid produced in the first part of the process, is used in the of making chloric of lime. A few years back, soda was got from the ashes of the plant called '• salsola soda," and sold in the form of an impure carbonate called " barilla." "^'ine is made from the juice of grapes. "UTien the grapes are ripe, they are gathered and at once put into a press, by wliich all the juice is squeezed out, and the skins, stalks, and seeds left in the press. This juice, which is called " must," is allowed to ferment, which it does of its o^mi accord, in the countries where grapes most abound, and at the season of the vear when they are gathered, without the addition of yeast or other ferment ; in a few days nearly all the sugaiy matter contained in the '"must" becomes con- verted into spirit, and it has now the pungent taste of wine ; (if the wine is allowed to ferment too long, it is very apt ±o become soui'), the ■\vine is now put into casks and kept for a time, during which a slow fermentation goes on, and that WI>~E MAKING. substance, ^vlaicll is called "tartar," is deposited in tlie form of a thick crust of an acidulus taste and brown color ; when purified till it is quite white, it forms the cream of tartar of the drus:ii;ists' shop. The color of wine depends upon the color of the grapes used, whether white or black. "Wine, at a general average, contains about 20 per cent, of spirit or alcohol ; when port Avine is put into bottles, a slow fermentation continues to go on, and a crust of tartar is deposited similar to that described above, and it is the separation of this tartar which causes port wine to improve by age. What are called British wines, are liquids mostly made by fermenting the juice of the fruits whose name they bear, as currant wine, gooseberry- wine, &c. ; but as the climate of this country is not favorable to the growth of grapes, or 38 MAXUFACTrEED PEODrCTS. the spontaneous fermentation of their juice, the grape wine of England is very inferior to the foreign. The juice of any fruit required to make wine of, has to be fermented artificially ; this is generally done by making it slightly warm, and floating on the surface a piece of bread soaked with yeast ; the wines thus produced are very apt to become sour, and it is generally necessary to add brandy to preserve them. Many of the British wines sold in London are made of an impure weak spirit called "faints," sweetened and flavored with various substances, as ginger, orange-peel, &c. and sell for erinsfer or orange wine. TI>'EaAB. Yinegar is produced by fermenting and exposing to the air any liquor which contains sugar, such as wine, infusion of malt, cyder, &c. ; by the addition of yeast, this sets up a fermentation, by means of which the sugar in any of these liquors is converted, first into spirit, and afterwards into MAXUFACTUEED PEODUCTS. 39 vinegar; tliis contains a certain quantity of acetic acid, ■which makes the vinegar sour. In warm countries, vinegar BOILEB OR COPFES. is made by siraply exposiug the poorer kinds of wine to the sun's rays, when they ferment and become soiir. In England, all the vinegar produced is made by fermenting wort made of malt, this is fermented for three or four days, COUlISG Al'FABArrS. 40 MA>'rFACTrr."ED PRODrcxs. and is then put into casks, with the bunghole left open for several weeks, or until it is thoroughly sour. In ordinary vinegar, there is about five or sis parts only in the hundred of real a^^etic acid, but this acid, when pure, is so strong as to bKster the skin when dropped on it ; it is often extracted from vinegar for chemical purposes, and to smell too ; for when scented, it constitutes aromatic vinegar. Vinegar, besides acid and Avater, contains a little unchanged spirit, much coloring matter, and some mucUage. Vinegar is chiefly used as a condiment, and for making pickles, and has considerable powers of preserving vegetable or animal substances; if common vinegar be distilled, a weak colorless acid comes over, commonly known as white or distilled vinegar. It is a common thing to sprinkle a sick room with ATaegar, under the impression that it has disinfecting properties, but this is an error ; although the odotu" is very refreshing. Vinegar has, of late, been made by means of the vinegar plant, which is a fungus, causing a species of slow fermentation, and converting the stigar or treacle tised into acetic acid. riU-IXG CAiKS. The heading of this section gives a good idea of the large scale on which vinegar is made ; being an accurate repre- sentation of the extensive works of Messrs. Beaufoy & Co. at Lambeth. COAL GAS. Gas, for lighting, is made from coal, by subjecting it to heat in iron tubes and collectiug aud puriiying the gas which is produced ; the following is a summary of the pro- cess : — The vessels in which the coal is put are called " retorts," they are six or seveu feet long, one-aud-a-haif 5i;cTION- OF RETOr.T. broad, and one high, generally fitted up six to a furnace, in such a way that the flame may entirely surround tliem (see fig. 1) ; from each retort an iron tube passes, and these all dip into a large horizontal tube, reaching nearly to its 42 MAyrrACTUBED PEODUCTS. bottom (fig. 2), this is the receiver for all the gas from the retorts ; it is connected Avith a pit for tar and ammonical liquor, which copiously condenses from the hot newly-formed gas. The object of causing the tubes to dip nearly to the bottom of the receiver is, that the fluid in it may close the end of each tube, and so prevent the gas returning when any of the retorts are opened for a fresh supply of coal ; from the receiver, the sjas passes by tubes beiit up and down inside of a great cistern of water (fig. 3) kept cold by a constant change of its contents ; this is the condenser, it causes the separation of all the tar and ammonia that remain ; but the gas is still contaminated with sulphur, and this is got rid of by causing it to pass into a broad iron cylinder perforated with holes and dipping into a reservoir of lime and water mixed together and stirred about with a machine contrived for the purpose : tlie gas enters this lime misture in hundreds of bubbles through the holes, and the MAirUFACTUEED PEODUCTS. 43 sulphur tlie gas coutains is attracted by the lime with which FIG. 3. it unites. The gas now rises to the top of this reservoir, which is, of coiu'se, air tight, and from thence passes for use to the gasometer ; this is the store-house where the gas is kept to supply the service pipes b, c, under the streets. The gasometer is made of plates of iron rivetted together. The lower part of this cylinder (see figs. 4 and 5) is received into a circular deep channel cut in the ground (h b, fig. 5) and filled with water, so that the gasometer d, which is suspended and balanced by means of the chains and weights e e, may be raised or depressed at pleasure. When the gasometer is (piite down, the inside of its top, a. rests on the ground ; when tlie gas enters, it raises it up till the lower edge is but a few 41 irA5TTACTrBED PEODrCTS. ioches below the water, and is prevented from rising higher bv fr-ames which support it ; when some of the weights, d d. are removed, the huge cylinder, a, slowly sinks down and forces the gas through the tubes, c c, to be burnt by thou- sands of consumers. About four cubic feet of gas is pro- duced from every pound of coal used ; the gas is lighter than air in. the proportion of 650 to 1000, and it is owing to this lightness that balloons ascend when filled with it, not from any peculiar power it has of ascending, but because the air, being heavier, presses downwards and forces it up. When gas is mixed with air it becomes very explosive, and when any escape is suspected iu a room, the windows of the room should be opened at tlie top. and the door also opened, before any light is introduced ; a few minutes will then suf- fice to ensure safety. One ton of good coal produces — 1 Chaldron of Coke, weighing 1494 lbs. 12 &allons of Tar ' „" 135 12 Gallons Ammoniacal liquor 100 9500 Cubic feet of Gas, weighing 291 Loss (chiefly water) ",, 220 2240 lbs. A cubic foot of gas weighs 514 and a-half graias. TAR. Tar is one of the results left in the distiUation both of wood and coal ; in places where wood is plentii'ul and tar in request, it is produced by burning the wood for that purpose ; and in some of the pits in which charcoal is pro- duced, an arrangement is made to collect the tar also. Coal- tar and wood-tar are different in some respects, and are both distilled to procure the napthas which bear the re- spective names. From wood-tar, crcasote is also extracted, and it is this substance which gives the peculiar tarrj flavor to proWsions cured or preserved by being smoked over wood fires, such as ham, bacon, or herrings. Tar is used as a sort of paint for covering wood- work and cordage, when much exposed to wet, which it resists better than am-thing else at the same price ; but the tar chiefly used for these purposes, is that produced by burning fir or deal wood and condensing the tar in a pit below the stack of wood, it is called Stockholm tar, as it comes chiefly from that place. 46 MA>'rFACTrEED PEODUCTS. ACETIC ACID, OE "n-QOD TIXEGAE. Acetic acid forms a considerable article of commerce. It is not only used in medicine and the culinary art, but is extensively employed in forming acetate of iron for dyeing and calico printing. To prepare it, large iron cylinders, about eight feet long and three in diameter, are embedded in brickwork in a row, and in such a manner that furnaces placed below may heat them red-hot ; these cylinders have a tube leading from each into a main tube, where the liquid products from each cylinder are received for condensation ; the other end of the cylinder has a plate of iron fitting closely to it. The cylinders are filled with logs of wood, either oak, beech, birch, or ash, the door is closely fastened and the joints smeared Avith clay ; the fires are now lighted and kept up all day, till the cylinders are red-hot ; at night they are allowed to cool. About seven or eight hiindi'ed weight of wood is put into each cylinder. In the morning, the charcoal, into which the wood is now converted, is with- drawn, and a fresh charge supplied ; from this charge of wood about thirty or forty gallons of liquid is condensed in the main tube from each cylinder, the remainder being charcoal and gases which pass ofi"; the liquid is acid, brown, and very oifensive, and contains acetic acid, tar, and several other ingredients, among which may be named creasote ; it is from this source all the creasote, so famous for the cure of toothache, is obtained. The next process is to purify this liquid ; it is first distilled, and this separates much tar, it is then mixed with lime, evaporated to dr\TLess, and heated to expel the remaining tar and other impurities ; it is next mixed with sulphate of soda and water and the whole stirred together, the soda, now in unison with the acetic acid, is washed out from the lime and strained quite clear ; it is after- wards evaporated till it crystallizes, and ^'itriol (sulphuric acid) then added ; finally, the acetic acid is distilled over, and the acid left in unison with the soda, forming sulphate of soda, to be used in a similar process for the next batch of acid ; the acetic acid is now quite colorless, transparent, and very sour, possessing a fragrant and agreeable smell. This acid is not pure acetic acid, but contains a considerable MANUFACTURED PRODUCTS. 47 quantity of water. The acetic acid of commerce, mixed witii seven times its bulk of "water, forms an acid of about the strength of malt vinegar, perfectly wholesome, and, to many, more agreeable as a condiment. Pure acetic acid may be made by mixing dry acetate of potasli with oil of vitriol in a retort, and distilling the acetic acid into a very cold receiver; this, when flavored Avith various volatile oils, forms the aromatic vinegar sold by druggists. It is a very strong acid, and if applied to the skin will quickly blister it. VARNISHES. Varnishes are solutions of various resinous substances that vnR dry with a bright surface on exposure to the air. They are used to protect different substances from the action of the atmosphere, and to give them an elegant bright siu-- face ; woods and painted work are the chief things varnished ; metals are coated with a kind of varnish called "lacquer," this is to prevent the bright surl'ace of the metal from being dulled by the air or damp, and to give an artificial appear- ance to some metals ; tin, for instance, if lacquered with yellow lacquer, acquires somewhat the appearance of brass. Mastic varnish is the varnish generally used for paper and pictures ; it is made by dissolving gum mastic in oil of tur- pentine. Copal varnish is that most generally used for car- riages and wood, it is made by adding boiled linseed oil to melted copal, and afterwards thinning it with od of turpen- tine. A common varnish, fit for many purposes, may be made by adding common resin to oil of turpentine, and warming it till dissolved. Lacquers are made by dissolving shellac and various other gums in strong spirits of wine, and in some cases coloring it, either yellow, by means of gamboge, or red, by dragon's blood (a kind of resin). French polish is nearly the same as lacquer, but the mode of applying it is different ; the grain of the wood is first filled up by means of drying oil and chalk rubbed in, when this becomes thoroughly dry, a rubber of flannel is covered by a piece or two of clean old linen, and some of the polish put on it, just enough to moisten it, and then a little oil, this is slowly 4S MA>'UFACTUaED PEODUCTS. rubbed round and round, the varnish adhering to the wood, and the oil preventing the rubber sticking to it, and at the t^ame time, polishing the surface of the varnish as it dries. This process requires a good deal of art to produce a perfect surface. Old -work, before being varnised with any varnish that contains oil (as copal varnish), should be thoroughly freed from grease or greasy matter, or the varnish will never dry. Grood varnish should dry in twenty-four hours so that dust will not adhere to it. PEES5IXG LIXSEED FOR OIL. OILS. Oils, whether animal or vegetable, have pretty much the same properties. The vegetable oils are got by crushing and pressing certain seeds, as linseed ; the animal oils are obtained chiefly from the whale and seal tribe, or trom fish, as the cod and sturgeon. They are ■\iscid and of a pale yellow color, lighter than water, and therefore float upon it, jmd are very combustible. Oils are used for a multiplicity of purposes : for burning in lamps, for making paints and \arnishes, preventing the friction of machinery, in making MANUrACTUEED PRODUCTS. 49 soap, and numerous other processes. Oils are generally divided iuto fixed and volatile oils ; as an example of the iirst, liuseed oil maybe selected; of the last, oil of lavender. Some of the fixed oils are called drying oils, and it is this kind that are used for varnish making; as linseed oil pos- sesses the properties of this class very perfectly, it may serve as a description of all. Linseed oil has the power of drying when spread out in a thin layer, becoming of a resinous consistence like varnish, and upon this quality depends the drying powers of paint, for the other non-drying oils, as olive oil, may be exposed to the air for months without drying at all ; the drying powers of linseed oil are greatly increased by boiling it with litharge (oxide of lead). This forms the drying or boiled oil used in painting, and is em- ployed in making varnishes, printers' ink, and for otlier pur- poses. Oiled silk is formed by brushing silk over with tliis oil and exposing it to the air till it is dry ; this oiled silk is the same that is used for sponge-bags and bathing-caps. Of the non-drying oils, the chief are those used for burning in lamps, as sperm oil. Salad oil is expressed from the olive, and is called oHve oil. Of the volatile oils, the most useful is oil of turpentine, commonly called spirit of turpentine ; it is got by distilling common turpentine (the concrete juice of trees of the fir and pine tribe), it has a strong odour, is very inflammable, and is volatile, that is to say, if spread out, wiU evaporate, leaving nothing behind ; this oil is capa- ble of mixing with drpng oils, and it not only increases their drying powers, but, by thinning them, makes them more applicable to many purposes. Oil of turpentine dissolves resin and many resinous substances, and forms useful var- nishes with them. Mastic varnish is mastic dissolved in oil of turpentine ; it is the varnish always used for varxiishing pictures. Many of the volatile oils are used as perfumes, and the odour of plants and flowers depends upon the vola- tile oil which evaporates from them, as lavender, cloves, and others. Peppermint water, dill water, and cinnamon water are produced by distilling water mixed with the substances, and is simply water containing a small quantity of the vola- tile oil of these substances in solution ; but eau-de-Cologne 50 MANUFACTURED PEODUCTS. and lavender water, althougli called "waters," are mixtures of volatile oils and spirit of wine, and contain no more water than is comprehended in the spirit used. INKS. Inks are fluids of various kinds suitable for writing with pens. The chief inks in use are black, blue, and red writing inks, and indelible or marking ink, intended for marking linen which has to be washed. Indian ink is not used as an ink, properly so called. All the black inks in use are com- posed of green vitriol (sulphate of iron), in union with some astringent vegetable matter, the best is the gall-nut, although, for cheapness, logwood and oak bark have each been used. An excellent black ink may be made by putting into a gallon stone bottle twelve ounces of bruised galls, six ounces of green vitriol, and six of common gum, and filling up the bottle with rain water, this should be kept three or four weeks before using, shaking the bottle from time to time. Blue ink has lately been much used, it is made by dissolving newly-formed Prussian blue in a solution of oxalic acid. To make it, dissolve some yellow prussiate of potash in water in one vessel, and some sulphate of iron in another, adding a few drops of nitric acid to the sulphate of iron ; now mix the two liquids, and a magnificent blue color will appear in the form of a light sediment ; this is to be put upon a paper filter, and well washed by pouring over it warm water and allowing it to run through ; a warm solution of oxalic acid should now be mixed with it, and the Prussian blue will dissolve into a bright blue ink. Eed ink is made by boiling chips or raspings of Brazil wood in vinegar, and adding a little alum and gum ; it keeps well, and is of a good color. A red ink of more beautiful appearance, but not so durable, may be made by dissolving a few grains of carmine in two or three tea-spoonfuls of spirit of hartshorn. Marking ink is made by dissolving nitrate of silver in water, and then adding some solution of ammonia, a little gum water, and some Indian ink to color it. Printers' ink is made by grinding drying oil with lamp-black. cn.vruCOAL. Charcoal is made by burning wood in such a manner tliat but little air shall be admitted during the operation, that is to say, only sufficient to keep up tlie combustion of the more easily destroyed parts of the wood, leaving a black residue ••ailed charcoal. The best charcoal is made when the wood is quite excluded from the air, as in making acetic acid, but where hirge quantities of charcoal are used for common fuel, as in France, of course this process is too expensive. The usual way is to pile up billets of wood and cover the whole with turf; when fired, the wood consumes gradually and the charcoal is left behind. Charcoal is light and porous, and of a shining black color ; it weighs about one quarter as much 03 the wood used, and burns without flame or smoke, giving out a strong henjt. "When charcoal burns, it combines with part of the air, and is converted into a gas called carbonic acid, which, although invisible, is much heavier than air, and is a deadly poison ; it is therefore necessary, where charcoal is burning, to always have some opeuiug at K 2 52 MAXUFACTUEED PEODUCTS. tlie hoitom of the room. ]\Iany fatal accidents have arisen from people sleeping in a small room with a pot of burning charcoal, and no outlet for the poisonous vapour but the chimney, up which it -n-ill not pass on account of its weight. Charcoal enters into the composition of gunpowder, and is used for several other pui'poses. It is an excellent sweetener of foul water, and a few pieces should always be kept in the top of the filter when the water has any bad odour, or in the cistern or butt, where a filter is not used ; powdered charcoal has also the power of taking away the color of many liquids, as well as the bad smell ; vinegar, if warmed with powdered charcoal, and then strained, will be almost colorless. Water butts ai'e sometimes burnt or charred inside, that the water may be the better preserved in them. Chemically considered, charcoal consists of carbon with a certain amount of earthy matter (the ashes or earthy part of the wood from which it was made), but these ashes may be easily removed by maceration in an acid ; the charcoal then remains unaltered in appearance and consists of carbon, but its structure is exceedingly porous. CEMEXTS. In various processes, cements of dilFerent descriptions are requii'ed for a variety of purposes. The common cement used in building, which is called mortar, is made of sand and quicklime mixed ^vith water. Eoman and Portland cements consist of certain kinds of clay burnt and ground. Plaster of Paris forms a useful cement, it is to be mixed ^vith water to the consistence of cream, and it hardens in a few minutes. Glue is an invaluable cement for wood and many other purposes, it also joins any kind of broken glass or china that will not have to be subjected to much wetting. Shellac dissolved in spirit is a useful cement ; and isinglass, dissolved in weak spirit, and having some gum ammonicum added to it, forms the " diamond cement" for uniting china. China and glass which require to be much wetted, are best united by being made very hot and having the broken edges rubbed with a piece of shellac, this melts on them, and forms, while hot, a sort of cement ; if they be immediately applied MAyrFACTURED PBODrCTS. 53 and pressed firmly and accurately to2:ether, and then per- mitted slowly to cool, they w'ill unite so as to be almost as strong as before breaking. COKE. Coke is produced by the partial burning of coal, in the same way that charcoal is from wood. The great source of coke is the gas manufactory, where it is sold in large quan- tities, being the result left in the retorts after the gas has all been driven off; but the consumption of coke by loco- motive engines, 'POWDEB. Gunpowder is a mixture of nitre, sulphur, and charcoal, and the more completely they are mixed, tlie more finely ground, and the pm-er they are, the more perfect will be the gunpowder. The proportions used of these ingredients difler slightly in diflerent powder mills ; but the average is about seventy-four parts nitre, ten sulphvir, and fourteen, charcoal, by weight ; the sulphur and nitre can easily be completely purified, but the cliarcoal difiers very much in almost every specimen, and charcoal that has been burnt long ago and exposed to the air and moisture is almost unfit for the purpose, that charcoal which has the least ash when burnt is found to be the best, and the charcoal which has been made in iron cylinders, is better than that made in the usual way, when each of the ingredients are separately powdered and sifted through a kind of sieve of silk called a bolting machine (such as is used in dressing flour), they are mixed in the proper proportions and taken to the mill, where they are moistened with water and ground to a smooth paste, 'this is pressed hard and then broken up into pieces which, are put into a copper sieve, the bottom of which is perforated with small holes ; a flat wooden ball is put into each sieve with the pieces of damp powder, and the sieves are all put into a circular motion by machinery, this causes the wooden ball to turn round in the sieve and so rub the damp powder through the little holes ; it is collected below in small grains or " corns," this process is called " corning," this is now dried, and then put into a "reel" (a sort of barrel which turns round) and the grains, by rubbing against each oiher, become smoothed on the surface ; the dust is now 56 MANUFACTrEED PEODUCTS. removed by a sieve, too fine to let the grains tlirough ; the powder is now fit for use. G-unpowder was first knoAvn in England about five hundi-ed years ago. It is not only used to discharge fire- arms, but in the more peaceful occupations of quarrying stone, mining, and to get rid of rocks both below and above water ; these processes are called " blasting." GUN COTTON. To prepare gun cotton, make a mixture of three parts sulphuric acid and one part nitric acid ; when this has cooled (for it becomes hot on mixing), put into it some cotton wool, and let it be stirred about with a glass rod, then taken out, and aU the superfluous acid strained from it ; it is then to be covered up for an hour or so. It should noAv be thoroughly washed in cold water, so that all the acid be removed ; to ensure this completely, let it be afterwards washed in a very weak solution of potash, and then dried by a very gentle heat, produced by either steam or hot water ; when dry, soak it in a solution of nitre and dry it again. It is now so explosive that great care is required in its manage- ment, being about tliree times as explosive as gunpowder. PnOSPHOEUS. This substance, since the general use of lucifer-matches, has become an important article of manufacture ; whereas, but a few years ago, it Avas a mere chemical cm'iosity. It is prepared by mixing bone ashes with sulphuric acid, straining ofi" the liquid part, and evaporating it to a syrupy consistence ; wdth this, about a quarter of its weight of powdered charcoal is mixed, and the whole stirred and evaporated to a dry powder ; this is put into earthenware retorts, which arc connected by copper tubes to receiver.^ filled with water ; the retorts are raised to a white heat and maintained at this high temperature as long as any phos- phorous passes into the receivers, the water' in which is kept warm, so that the phosphorous melts and runs to the bottom, from whence it is taken and strained through cha- mois leather bags, under warm water, and then cast in glass MANUFACTUUED PEODUCTS. 61 tubes into sticks. Phosphorous is of a whitisli color, like wax, is easily melted, readily takes fire even by slight fric- tion, and, in the air, gives oft' fumes which in the dark appear luminous. It is chiefly xiscd in the manufacture of lucifer matches, and, mixed with flour, butter, or sugar, is used to poison rats, mice, and other vermin, under the name of " phosphorous paste." Phosphorous is poison, and most dangerous stuft* to handle, minute particles often getting under the nails and causing painful sores. WUir£ LEAD BED. WHITE LEAD. "Uliite Lead is used in very large quantities by painters, not only as white paint, but to mix with and qualify every shade of color, and to give body to them. It is prepared by different processes, and several patents have been taken out for improvements in its manufacture ; but the most usual, and, perhaps, the best process, is as follows: — A layer of spent tan (from the tanner's pits) is spread out three or four feet thick, and in it a number of eartheru pots are 3 n n 68 lIAyrFACTURED PHODTJCTS. arranged in rows, each partly filled witli a mixture of vinegar, water, and treacle, or some other acid fermenting liquid, each of these pots is covered with a piece of lead made in the form of a grating (fig. 1), and over all these a flooring of boards, and then again a layer of tan, pots covered with lead, and boards, two or three times repeated ; this is called a white lead bed, and is left for several weeks ; the tan ferments and gets warm, causing the acid vapours to rise and corrode the lead, at the same time ^^^- ■^• giving oif carbonic acid. At the end of about three months the leaden covers are found to have become completely changed into a white shining substance (carbonate and oxide of lead), this is washed from impurities and ground in a miD, under water, to a fine powder. It is the white lead of com- merce ; but what is familiarly called white lead, is this sub- stance ground up with linseed od. into a thick paste so as to be ready for the use of painters. "White lead is a very poisonous substance, and produces the disease called painters' colic, when taken into the system in minute quantities and for a long time, so that all who have much to do -n-ith this dangerous substance, as house- painters and artists, should be extremly careful that their hands are well washed frequently, and especially before going to meals. Cisterns of lead, used for containing water, very soon become coated inside with a thin Aim of sulphate of lead, this prevents the water from acting further on the lead, and the water from such cisterns is never found to be poisonous ; but, if distilled water were used, it would act rapidly on the lead, corroding it, and causing a deposit in the water of white lead, which would render such water dangerous in the extreme. PEL'S sia:s" blue. Tliis beautiful blue color is made by mixing solutions of sulphate of iron (green vitriol) and prussiate of potash together, when the Prussian blue falls in the form of a MAXUFACTrEED PEODUCTS. 59 precipitate, or moist powder, of a pale greenish color, but which, by exposure to the air aud the addition of a little nitric acid, becomes intensely blue ; but the Prussian blue of commerce is never pure, for the solution of prussiate of potash is used as it comes from the factory, before being crystallized, and contains carbonate of potash, to get rid of ■which, alum is added, and the result is, the formation of a considerable amount of alumina, which is a white earth pro- duced from the alum, and which falls doAni in the precipi- tate mixed with the Prussian blue, which is thereby increased in bulk and but little injured in color ; when a larger quan- tity of this alumina is purposely produced, the result is a blue of a rather less intense color, called '"Antwerp blue." The chemical name for pure Prussian blue is percyanide of iron. Chinese blue is this substance in its purest state. PETJSSIATE OF POTASH. Prussiate of potash is the commercial name given to what chemists call " lerrocyauide of potassium," it is used largely lor the production of Prussian blue, and also in the art of electro-plating, which, of late, has greatly increased the demand for its mantifacture, and many patents have been taken out for various modifications in the form of production, the result, however, is the same, and it occurs in commerce in magnificent crystals of a square form, with bevelled edges, and of a yellow color ; there is, however, another kind called the " red prussiate," which is much used in the process of calico printing. Prussiate of potash is made by heating together carbonate of potash, scraps of iron, and any kind of animal refuse, as blood, honis and hoofs, clippings of skin or old woollen rags ; these are stirred together, and the heat raised, till they form a sort of paste of a black color, which, when cold, is thrown into water and all the soluble parts washed out ; this fluid is filtered till quite char, eva- porated, and set aside that crystals may form ; these are dissolved and again crystallized, 'ihe red prussiate is made by passing chlorine over the yeUow prussiate in powder dissolving and crystallizing. The most deadly of all poisons, prussic or hydrocyanic 60 ilA^TFACTUEED PEODUCTS. £cid., is obtained from the ferrocyanide of potassium, or pnissiate of potasli, by adding diluted sulphuric acid aud distilling the vapour into an ice-cold receiver. This experi- ment should never be made by any but those well conversant with such matters. SrLPHATE OF lEO^", Also called " Grreen Vitriol " and " Green Copperas," is a combination of sulphuric acid and oxide of iron, and may be made by putting iron filings or pieces of iron into a mixture of sulphuric acid and water, and when all action has ceased evaporating the liquid, and setting it by till crystals form — these are of a pale green color. The sulphate of iron of commerce is formed by exposing the iron pyrites foimd in the coal districts to the air till it falls to powder ; water is then poured over this substance, and the fluid collected and evaporated. Svdphate of iron is used chiefly to form the black dye so much in demand to dye cloth, and also in making writing ink. SrLPHATE OP COPPEK. This substance is also known by the names, "Blue Vitriol " and " Blue Stone." It is a combination of sulphiiric acid with oxide of copper, and may be made by uniting those substances ; but what is used on a large scale for commercial purposes is obtained from the waters which flow into copper mines where " copper pyrites " abound ; this water is evaporated, and the sulphate of copper crj'stallizes. Sulphate of copper has of late been in great demand for the electro-deposition of copper. CHLOEIDE OP LIME. Chloride of lime or " bleaching-powder " is made for the purposes of bleaching calicoes, linens, &c., and also for purifying foul air, which it does by giving out chlorine, a gas capable of luiiting with and changing the injiu'ious properties of foid air (which generally contains some com- bination of sulphur and hydrogen). Chloride of lime is made on the large scale by mixing hydi'ochloric acid with MA^'^FACTUKED PEODrCTS. CI "black oxide of manganese. This mixture gives off clilorine. This is made to pass over a layer of slaked lime, which absorbs it greedily, and becomes converted into the bleaching powder. The hydrochloric acid used is a product resulting from the manufacture of soda, and was formerly wasted ; it is now used in large quantities for the process above described. " Burnett's Disinfecting Tluid " is a solution of chloride of zinc. It is made by dissolving scraps of zinc in hydrochloric acid; hydrogen gas is given off, with effer- vescence, and the liquid remaining is the solution of chloride of zinc, which acts like chloride of lime, by giving off chlo- rine ; for the chloride is slowly decomposed by the air, the oxygen of which takes the place of the chlorine, uniting with the zinc to form oxide of zinc, while the chlorine is set free. SLLPHUBIC ACID. This was formerly called " Oil of Vitriol," because it has an oily consistence, and was originally distilled from green vitriol. Sulphiu-ic acid is one of the most useful chemical agents known ; scarcely a process in chemical manufacture can be performed without its assistance. Sulphuric acid is colorless, and very heavy, being nearly double that of water (the proportion is 1842, while water is 1,000) ; it is powerfully acid, even when largely diluted with water, and during tliis mixture with water gives out great heat, a mixture of equal parts \viU become hotter than boiling water ; if it be mixed, however, with snow instead of water, it becomes extremely cold (below zero). Sulphuric acid is made by burning sulphur in a furnace, and causing the vapours to pass into a large chamber lined with lead, and having some water at the bottom ; into this chamber the vapours arising from nitre mixed with sul- phuric acid are also admitted, together with air and a jet of steam. These arrangements require to be ])roperly and nicely regulated, and it was only by study of the com- plicated changes which take place between these gases (sulphurous acid, nitric oxide, and atmospheric air), that this arrangement has been densed and adopted, a great part of the product having been formerly v.asted in a more 62 MAyrPACTVEED PEODL'CTS. clumsy mode of preparation. The sulpliuric acid con- densed in tlie water at the bottom of the leaden chamber is too weak for use, and is concentrated by evaporating the water from it ; for this purpose it is placed in shallow leaden pans placed on the bars of a furnace, and finallv distilled in glass retorts, or retorts of iron lined with platinum. Sul- phuric acid has such a powerful attraction for water, that an open vessel half-full of strong acid placed in a damp situation will attract enough water from the atmosj)here to cause it to be quite full before long. This power of attracting water has been taken advantage of to procure ice in those places where it is not to be had naturally, as India, &c. If a vessel of water be placed under the receiver of an air-pump, and the receiver exhausted of air, the vapour of the water will speedily fill it, taking the place of the air, and so stop any fuither evaporation ; but if another vessel containing some sulphuric acid be placed also in the receiver, the acid will absorb the vapour of water as fast as it is formed, and this rapid evaporation continuing produces such cold, that the remaining water is shortly frozen. Iron and zinc dissolve rapidly in diluted sulphuric acid, giving olf abimdance of hydrogen gas, and this was the way this gas was formerly produced for the inflation of balloons, but the common coal-gas being easily obtainable in almost any quantity in all towns, it is now used for that piu"pose instead of hydrogen gas. Sulphuric acid (chemically con- sidered) consists of 1 equivalent of sulphur with 3 of oxygen, and 1 of water. Pui'e sulphiu"ie acid (without water) is in the form of fine crystals, much resembling snow, which, on exposure to air containing the slightest quantity of moistiu'e, absorbs it, and becomes converted into the ordinary sulphui'ic acid. If this acid (even when greatly diluted) be spilt on cotton or linen it destroys it, producing a hole ; this is owing to the acid converting the iibre into sugar. A proposition Avas once made to produce sugar from this source, but linen and cotton rags are in too gi'eat demand for paper-making to aUow of its being done. TAS-TAKD A5D PITS. LEATHEE. Tanning is the name given to the process for converting tlie skins of animals into leather, by combining them with a substance called " Tannin." This tannin exists in many vegetable substances, such as oak-bark, gall-nuts, catechu, sumach, &c. : all of these, and many more, are used for tamiing, but, on accoiint of its cheapness, oak-bark is the usual substance employed. It is tannin -which gives the quality of astringency to many vegetables, and this very taste of astringency is produced by a partial combination of the tannin with the surface of the mouth. The skins (called "hides" or "pelts") are first freed from all loose pieces of flesh, fat, or skin ; the hair is then removed by soaking them in lime and water. The skiua G4 MANUFACTUEED PEODUCTS. are then laid in the " tan-pit " between layers of crushed oak-bark until the pit is nearly full ; water is then pumped in, and the whole is allowed to remain for several weeks or months (according to the thickness of the skin), during which time, however, the skins are changed in position by re- moving them from one pit to another with fresh bark in it, so that those taken from the top of the first are placed at the bottom of the next ; and this is done from time to time, in order that all may receive the same pressure and strength of tan-liquor. Very thick hides take a year to tan perfectly in this way, and conse- quently many processes have been tried to quicken the (operation ; but the leather made most slowly seems to wear the best, and consequently fetches the higher prices. rNHAIEIJfS THE SKIS. DETIXG EOOJia. Skins which are thin, and to be used for fancy work, and for book-binding and glove-making, are either tanned with " sumach," or with alum and salt made into a paste with MAXrFACTURED PRODUCTS. 65 flour and yolk of egf?s ; this is put into a tub, and the mixtiu'e and skins worked together with the hands till they are thoroughly united. SUiLtCn TAN TUBS. Besides boots and shoes, leather is used for tlie harness of horses, covers for seats, gloves, and innumerable other purposes. For some purposes the leather is required to be very thin, and of exactly one thickness. This is obtained by the process of splitting, for which a machine is used whose bPLITXISG MACUIXE. exactness is such, that one slice is taken from the inner part of the whole skin, reducing it in thickness without cutting a hole in any part. The skin is stretched tightly 06 il-O'rrACTUBED peoducts. round a roller, -n-hicli slowly revolves against a straight knife-edge, fixed at a certain distance from it, according to the thickness of the skin, and which is passed by the machine backwai'ds and forwards, cutting the skin a little further each time. GirE A>'D SIZE. Glue is made from the clippings of iides or any other refuse of skins, horn shavings, bones, &c. All these substances are piled up in a boiler having a second bottom within, perforated with holes, and kept from the true bottom by short feet : this arrancjement is to prevent the substances boiled fi'om burning at the bottom of the boiler. After many hours' boiling the liquid is tested, and if it •' sets " into a sort of jelly readily, the liquor is dra^^Ti off into another boiler, where it is kept warm, that it may not set till used. From tliis boiler it is strained through flannel into square wooden boxes, ha-^-ing ridges at the bottom dividing them into squares (to direct the workmen where to cut the glue when cold) ; these boxes are set apart, and when the contents have become cold and set into a firm jelly, a knife is passed between the sides of the box and its contents, and the glue turned out in a large solid square. This is now cut by means of a wire with a handle at each end into squares of about eight inches each way and an inch thick ; these are now placed on nets made of cord fixed in frames one above another in a •' drying-room," which is open to the air at the sides, and able to be closed up in case of wet weather. In this room the glue dries up, slirinks, and hardens, until it is quite brittle ; the marks of the net can be seen on every square of glue. Size is the same as glue, but instead of being dried it is put into small barrels. Two qualities of size are made, single and double size. It is much used by whitewashers, paper-hangers, and others, but for any purpose requiring good size, it may be made by soaking isinglass or gelatine in cold water till it is softened, and then standing the vessel in boiling water till it is dissolved ; this produces a jeUy nearly pure. A cheaper kind of size, almost as pure, may be made MANUFACTURED PRODUCTS. (57 by boiling clippings of clean parchment till they are dissolved, and straining oft" the solution. Gelatine is the same as glue, but made of materials that are clean and fresh. Isinglass is the "sound" or swimming-bladder of the sturgeon, cleaned, dried, and cut up into fine shreds. PARCnMENT. Parchment is prepared from the skins of sheep, goats, calves, and asses. Sheep-skins furnish by far the greater part of all parchment prepared, indeed all that which is used for deeds and law purposes. From whatever skin prepared, it is first soaked in lime and water to remove the hair and greasiness, and then stretched tightly on a frame, and the siu"face rubbed smooth with pumice-stoue, after which the skin is allowed to dry. Parchment is used for deeds, which require to be very diu-able and not easUy torn, both of which qualities it possesses much more than any kind of paper ; it is also used for book-binding, drum- heads, and many other purposes. Clippings of parchment boiled for some time, and the liquid strained oft", forms an excellent colorless size. Vellum is a thick kind of parch- ment, made chiefly of calf-skin. CATGUT. What is called catgut is made from the inner or lining membrane of the intestines of sheep. These are washed, soaked, scraped, and other\vise prepared, to render them even and clear; they are then soaked in a solution of jjearlash to clear them from grease, twisted, exposed to the vapour of sulphiu*, polished by rubbing, and afterwards stretched and dried. Catgut is used not only for the strings of violins and other musical instruments, but also for what is called " clock-makers' cord," that is to say, for the bow by which the drill is turned, and for several other purposes. It is very strong, and does not easily get ragged, as would any hempen cord. F 2 PIG. 5. HASD PROCESS. PAPEE. This important article of civilisation is made from rags of various descriptions and qualities, according to the kind of paper to be made, the finest white paper being made of old clean linen rags, while brown paper is made of all sorts of old rope-yarns, sacking, &c., and some kinds of paper have a considerable amount of straw bleached and worked up in them. The rags are first sorted and cut up into smaU riG. 1. SECTIOX OF EAG EXGIXE, nVITH DOUBLE KOLLEE. pieces ; they are then beaten on a wire screen to separate all dust, and afterwards put into the washing-machine, through MANFFACTUKED PRODUCTS. G9 which a stream of water runs, and in which they are kneaded and torn by a broad wheel having iron wedges or knives fastened to its edge (fig. 1) or surface, whicli work as it is turned against knives of a similar description fastened to the bottom of the cistern. "Wlien the rags are thoroughly washed, and at the same time torn to a coarse pulp, it con- stitutes what the workmen call •• half- stuff"." This is mixed with chloride of lime, and the machine again set in motion ; this is for the purpose of bleaching the piUp ; after this has been effected, more water is turned on, as in the first washing, and all the chloride of Kme washed thoroughly away. The pidp is now either put into another machine of the same clescription which cuts sharper and finer, or else tlie same machine used at first is so screwed up as to cause the knives to come more close- ly together; in either case the rate of turning is greatly increased, so that the wheel turns at about 150 revolu- tions per minute, and completely grinds up the pulp till it is perfectly smooth : at this part of the j^rocess some " indigo " or " emalt " is added if the paper is to be of a blueish tint, as in " foolscap " paper. The " stuff"" is now run off" into a cistern ready for use. Paper is now nearly all made by machinery, in pieces of a certain width, but of an indefinite length, and is cut up into sheets afterwards by a " cutting machine." 70 MANUFACTURED PRODUCTS. These maeliiiies (fig. 2) consist essentially of a yat, a, for the pulp, which flows out on to a bed of wire gauze, b b b, covered with felt, and bounded on each side by straps or deckles, and forming a circle or endless band by being stretched over a succession of rollers, c d E r g, which, by turning roimd continually, move its upper surface onwards and between other cylinders, which press out the super- fluous moisture ; it is then carried forward till it arrives at several pairs of large hollow cylinders, H ii h, heated by means of steam which is passed through them, and which compress and at the same time thoroughly dry the paper, which comes from them as paper perfectly formed, and of any length that may be required. It is then glazed on the surface by the rollers i, and coiled on the cylinder l. Any name, device, or water-mark can be worked in the bed on to FIG. 3. SIZING MACHINE. which the pulp flows, and which, being repeated at definite distances, appears on each sheet into which the paper is afterwards cut. The apparatus marked k is to conduct to the earth the electricity developed by the friction of the paper against the rollers. Beneath the bed of wire gauze, MANUFACTURED PBODUCTS. 71 on wliich the pulp is laid is a cavity from which the air is pumped, and which causes the air to press upon the surface of the pulp, and force out a great deal of its moisture. If the paper has to be sized (which is the case in all '• hard " papers) it has to pass through a process, the machinery of which is sliown in fig. 3. a is a reservoir for size. B a trough for the paper to dip into, c the reel of paper to be sized, d rollers to press out all superfluous size, z a pulley to keep the paper on the stretch, f f f a succession of hollow " drums," to prolong the passage of the paper through the air of the drWng-room, which is heated by the furnace g and the tubes i i. h h are openings to admit fresh air, and k openings to allow the exit of the steam from the paper as it dries, l is a series of rollers to glaze it. FIG. 4. CUTTIXG \LLCniXK. The " cutting-machine " before referred to is represented at fig. -4. A is a wheel upon which is fixed a plate ^\-ith pro- jections and screws for fixing the position of the ann attached to the link b ; b link connecting the wheel a with the lever- arm G, and capable of adjustment by means of the plate attached to the wheel a., and the screw d ; d a screw 72 MAyrFACTUEED PRODI" CTS. regulating the position of the rod b ; e the drum by whose motion the web of the paper is carried forward. But the process, as conducted by hand (fig. 5), Avill give a much better notion of how paper is formed from the pulp. A reservoir, a, is filled -R-ith pulp, which is supplied by a wheel in the box b, to a strainer c, and passed to a vat d, and a man, e, takes in his hands a mould consisting of a shallow frame of wood of the size the sheet of paper is to be, having a bottom of fine wires laid side by side, and having wires crossing at intervals to keep them firm (the marks of these may be seen in any sheet of laid foolscap paper held up to the light) ; he dips this mould edgewise into the reservoir, and brings it up horizontally fuU of pulp ; this he gently shakes, to make the pulp lie level and allow aU superfluous water to di'ain through the wires. It is then handed to another man h, who has a sheet of flannel or felt spread out on a table r G, on which the mould is inverted, and the sheet of pulp left on the flannel, which sucks up more of its moisture ; over this is placed another piece of flannel, and then another sheet of pulp on it, and so on to the nimiber of five or six dozen F, then the whole is put into a powerful press, and screwed down till aU the water is squeezed out, when they are pretty firm, and are lifted out and hung on lines to dry, after which they are immersed in a cistern fiUed with thin size made by boiling clippings of skin in water (see " Glue and Size "), and having some alum dissolved in it — they are once more pressed and dried. AVhat is called "hot-pressed " paper is pressed between smooth sheets of pasteboard, having a hot iron plate placed between every three or four dozen sheets of paper; this gives a smooth surface to the paper. The names, dates, and other nihrks seen on hand-made paper are formed by wires worked into the bottom of the mould, which, projecting, make the pulp thinner in those places. The water-mark of Bank-notes is made in the same way. More than haK-a-million sterling is paid annually for duty upon paper — so vast is the consumption ! MAXUFACTURED PRODUCTS. MALT. Barley is the grain generally chosen for producing malt, altliough others may be used. It is first soaked in cold water till it is softened ; it is then spread out about two feet thick on the floor of the malt-house, where it begins to germinate, in the same manner as if so-rti in the earth ; this is allowed to go on so lar only till the first part of the root and stem make their appearance, in the form of a little bud and a fibre. During germination the malt gives out a poisonous gas called " carbonic acid," and becomes warm, in fact it woidd become too warm and be injured, but it is kept stirred by means of wooden shovels from time to time, and the temperature ascertained by means of a thermo- meter. As the process of germination goes on, all the starchy matter natiu-ally contained in the grain becomes changed into sugar, and the malt, when made, has a sweetish taste. As soon as the germination has proceeded to a certain extent it is stopped by drying ; for this purpose the malt is put into a kiln and heated almost to scorching — if but slightly, it is called pale malt or " amber," if more, " brown malt "or roasted malt. ]\Ialt, if kept dry, wnll remain a long time unchanged. It is used for producing beer and vinegar, and for " wash," from which all the raw spirit used in Eugland is distilled. AVhiskey is also distilled in Scotland and Ireland from malt. ^lalt has the property of converting the starch of barley unmalted into sugar while in contact with it. For example, if barley were ground and boiling water poured on it, it would form a thick sort of paste, which is because it contains starch only ; while malt treated in the same way, sinks to the bottom, and leaves a clear limpid "wort," which can be strained off, because the starch is changed into sugar, which is soluble. Now, if equal parts of malt and ground barley be also treated in the same way, the malt very shortly converts the starch of the barley into sugar, and the result is the same as if all had been malt. This was once a matter of great importance to the brewers, who thereby saved the heavy duty imposed upon malt. CHOCOLATE CEUSHISG MACHIXE. CHOCOLATE A>'D COCOA. Chocolate and cocoa are made from the seeds or beans of the Tlieobroma Cacao. The fruit of this plant somewhat resembles a cucumber, and contains from twenty to thirty seeds ; these are dried and packed for the market. They come to this country from the West Indies (Berbice and Demerara). The beans are roasted in an iron cylinder with holes to let out the vapour, &c. ; when cool they are deprived of their husks, and then crushed by means of rollers turning on a flat slab, kept warm by stoves or steam. The seeds when crushed on the warm slab become almost liquid, owing to a kind of butter or concrete oil which they contain, and which melts by a gentle heat. When the seeds are rolled by the machine into a smooth paste, this is either put into a mould of tin and formed into squares and various other forms, or left rough as it is scraped from the slab (this is called "rock" cocoa). For chocolate it is mixed with sugar, and either dried and powdered, or made, as the cocoa, into paste. On the Continent it is flavoured with " vanilla." liESSEilEK'S PROCESS. STEEL. Steel is usually made by a process called " cementation." Bars of the best Swedish or Eussian iron, about six feet long, are placed in an iron box, the bottom of which is covered with a layer of charcoal powder ; over the first row of iron bars some more charcoal is put, and then another row of iron bars, and so on till the box is fidl, when it is carefully closed and kept at a white heat for four or five days. "When cold, the bars are found to be converted into steel, and, being rough and blistered on the surface, are called " blistered steel ; " this is bi'oken up, and the bars laid side by side and made hot in a forge, where they are welded together by tlie blows of a heavy hanuner, and 7(3 MAyrrACTUEED PEODrCTS. dra\ni or rolled out by mackmery into bars of '"'fine steel." Steel differs from iron in the closeness of its grain, in being very much " tougber," and in having that very useful and pecvJiar property called "temper," which is the power of hardening when suddenly cooled while red-hot. If a bar of steel as soft as iron be made of a bright red heat, and then suddenly plunged into cold water, it will be found to have become harder than any other metal (so hard, indeed, that it will scratch glass), and is as brittle and readily broken as flint or glass. If now a gentle heat be applied to it, this extreme hardness of temper gives way. For instance, if a piece of bright hard steel is held for a moment in the hollow of a clear fire, a pale straw color appears on its surface, it is now still very hard (but not so hard as before), and is fit for razors, surgeons' instruments, &c. ; but if held in the fire a moment or two longer, it becomes of a bright golden yellow, and is fit for penknives, and other cutting instruments ; held longer still, it becomes bright blue, and is fit for watch-springs, swords, and other purposes requiring great elasticity but no great hardness; if the heat be carried still fmi:her a brown tinge is seen, and it is now rather soft, but greatly harder tlian iron, and is still elastic ; saws, coach- springs, and many other ai'ticles are made from steel at this temper. If the heat be caiTied on to redness, the steel would be quite soft when it had slowly cooled, but if suddenly cooled (as by being plunged into water) the original hard temper comes back again. Steel, like iron, may be cast, and cast-steel is one of its most useful forms, and much resembles " fine steel." The mode of preparing cast-steel is to melt the " blistered steel " in a cimcible, or earthen pot, and then run it into a mould : this forms an " ingot " of steel, which may be after- wards rolled or welded as the case may require. Steel may be drawn into very fine wire, or wrought into the most minute articles, as the springs and other parts of watches. It bears a very fine and bright pohsh, and does not nist or tarnish so easily as ii'on. It has lately been proposed to make heavy cannon of cast-steel, which is much tougher than either cast-iron or gun-metal. MANUFACTURED PKODUCTS. 77 A process has lately been invented by Bessemer to super- sede the lonn; and laborious process of "puddling." It consists essentially of transferring the melted iron into a vessel in which there are tubes inserted at the lower part, and through which air is forced at a great pressure, which bubbles up in streams through the mc4ted metal, and, as it does so, imites with the carbon and sulphur of the iron, converting them into carbonic and sulphurous acids, and at the same time producing an increased heat, which is quite necessary to the success of the process, for as the iron becomes piirer it also becomes more difficidtly fusible, and would set into a solid mass, but that this greatly increased temperature keeps it fluid. This rising of temperature is PBRPEXDICULAK SKCTI058 OF C05TKRIING VESSEL. similar to what takes place upon blowing a common fire with bellows ; for the more air that is admitted io carbon raised to a very high temperature, the more rapidly does it combine with its oxygen, or, in other words, the more rapidly does it bum. So that, in this process of Bessenicr's contriving, the carbon of the iron acts as fuel to keep up 78 MA>"rFACTUEED PEODUCTS. FIG. 3. the heat necessarr to maintain its fusion, and at the same time, by being converted into carbonic acid, escapes in bubbles (like the bubbles which escape from soda-water), and this rapid production of gas in every part of the fused iron also assists in brincnng about a thorough stirring-up and mixing together of all its parts. Eeference to the accom- panying diagrams Avill illustrate the working of the process. In figs. 1 and 2. a b are lower chambers, c is the melted iron, D is an upper chamber for melting scrap-iron, &c.. i: ia fig. 1 and D in fig. 2 are openings for the escape of gas and flame, r F is an air-passage running all round and communicating by & with the tuyere-holes shown at e in fig. i, h is the fire-brick lining to the fur- nace, and I the tapping-hole through which the fluid iron is discharged. In fig. 3, i is the tapping-hole, k the main air-tube leading from the blast-engine, l l perpendi- cular tubes (marked & in figs. 1 and 2) leading from cir- cular air-passage to tuyere- holes, ii is an opening for the insertion of iron into the upper chamber, opposite to opening d in fig. 2, and >" the tap for regulating the blast ; o indicates the outer casing of wrought iron. "Wlienthe process is carried only to a certain point, the result is a sort of semi-steeL which the inventor of the process expects will be a very useful article of commerce. During the bubbling up of the whole mass of iron and the extreme elevation of temperature caused by the union of the carbon of the impxire iron with the oxygen of the air. the oxide of iron as fast aa it forms fuses into a sort of OVTalDE VIEW OF C05VEKTIXG VESSEL, MAXUFACTUEED PRODUCTS. 79 glass, and this unites -with the earthy matters of the impure iron and tloats on the upper via.i. part as a flux, thus ridding the cast-iron of all its impurities, mth no other fuel than that contained in the iron itself and the air. The accompanying illustra- tion represents a horizontal section or plan of the con- verting vessel ; A the central chamber, b a lining of fire- bricks, c the main air-tube, D the tapping-hole, e the tuyere-holes through which the air is forced into the melted iron to be purified, f is the outside casing of wrouffht-iron. HOEIZOXTAl SECTION' OE PLAN OF COXVEETIXG ^"ESSEL. TIX-PLATE, AXD GALTANISED lEOX. What is usually called tin is, in fact, sheet-iron coated with tin, and of this tin-plate, kettles, saucepans, &c., are made. The art of coating iron plates with tin has been practised in England hardly more than one hundred years. The verj' best soft iron is used for the purpose of being tinned. It is rolled out into thin plates, which are cut by shears into squares of usually thirteen inches long and ten broad, these plates are dipped into weak acid to clean their surfaces, then rubbed with sand, and finally washed ; they are next dipped into melted tallow, which presenes their siu'laces bright till they can be used. They are then inunersed in melted tin, which has its surface covered with melted tallow, to keep it from being converted into oxide. When the plates have remained for a short time in the tin, they are removed, and the superflnous tin is mped from the lower edge with a brush made of hemp, and then cleaned from the grease with dry bran. The objects gained by coating iron with tin are, increased beauty of appearance (for when tinned ware is kept bright, it has almost the so ArWTFACTrTfF.D PRODUCTS. color of silver), and a protection to keep the surface from rusting, and consequently being corroded into holes. Copper and brass vessels are tinned inside, to prevent the formation of that poisonous substance called verdigris. The mode of tinnina: them is as follows : — They are cleaned inside by means of A'itriol, and then made hot, fine graia-tin and a little rosin being put into them, and turned about and brushed over the surface with a ball of tow : by this means, the tin is equally spread over the inner surface of the vessel. Tin-tacks, buckles, and other small articles, receive a coating of tin by being put into an earthen pot together with some grain-tin and a substance called "sal ammoniac," and the pot being heated over a fire sufficiently to melt the tin, is then shaken up till the articles inside have received a coating of tin. Iron plates have lately been coated with melted zinc instead of tin, and the surface thus covered enables them to be u^ed for various purposes and in situations where they are exposed to the action of the weather, as on house- tops, &c. The plates, thus treated, are called "galvanised iron," and they are generally used in a corrugated form. They withstand the action of the weather very much better than simple ii-on plates would, for the latter would be very soon eaten into holes from rusting. GLASS. This most useful and elegant material — now an article of almost universal application, in various forms — is made on a very large scale by fusing together sea-sand and alkali (either potash, soda, or lime), and, in the case of " crystal," or " flint-glass," oxide of lead. The following is about the composition of the chief kinds of glass in use ; — FLnrr gjulss. _ pakts. plate glass. pabts Pure vrhite sea-sand ... 52 Pure white sand 55 Potash 14 Soda 35 Oxide of lead 3i Xitre 8 Lime 2 100 100 MA>"U1ACTURED PRODUCTS. 81 CBOWIf GLASS. PARTS. GKEEX BOTTLE GLASS. PARTS. Sea-sand SO Salt 10 Lime 10 Fine white sand . . . Chalk ... 63 ... 7 Soda .. 30 100 100 FHnt-glass or " crystal " is very heavy, moderately soft (being easily cut with a file), and very bright and white. It is used for all table-glass, as decanters, wine-glasses, &c., and for the drops or lustres of chandeliers. Plate-glass is that kind of glass now in such general use for shop- windows, looking-glasses, &c. It is cast on flat iron tables, and rolled out to the sizes required, then cut and polished by machinery. In the rough state it is called "rough plate," and is the substance used in the Crystal Palace, and has of late become almost a substitute for groiind glass, which is simply ordinary glass ground or roughened on the surface by means of sand, so that it will admit light and yet not allow objects to be seen through it. Crown- glass is the ordinary' " \\"indow- glass." It is made in great circular pieces (see "Glass-blowing"), and cut up into the sizes required. Cro\\Ti or window- glass made some years back, had a disagreeable tinge of green, which has been removed in modern glass by the addition of a minute quantity of oxide of manganese. The ingredients to be made into glass (of whatever kind it may be) are thoroughly mixed together and thrown a little at a time into large crucibles or melting-pots placed in a circle (a a, fig. 1) in a furnace resting on buttresses (b b, fig. 1), and heated to whiteness by means of a fire in the centre, c, blown by a blowing machine, the tube of which is seen at D. This furnace is shown in perspective in fig. 2. The ingredients melt and sink down into a clear fluid, throwing up a scum, which is removed from time to time. This clear glass in o 82 MA>"UrACTrEED PEODrCTS. the fosed state is now kept at a white heat till all air- hubbles have disappeared ; the heat is then lowered to a bright redness, when the glass assumes a consistence and ductility suit:.' ' : tl^e pnqiose- .' :■ r ^lass blower. Artificial gems are all but varieties of glass. "UTiat is called " paste," " French diamonds," &c., are glasses of pecvdiar brilliancy, well cut and polished. Grarnets, eme- ralds, and other precious stones are imitated by coloring the " paste " with various substances, chiefly metallic oxides, as oxide of cobalt, which produces a blue color, oxide of copper a red, and oxide of chromium a green color, &c. Grlass is used for a variety of purposes besides the one great purpose of admitting light to houses while air and damp are excluded. It famishes an immense variety of beautiful and usefid articles in the form of drinking- vessels, vases, chandeliers, &e., and to the chemist and manufacturer generally, it is invaluable, for vessels of glass thoroughly resist the action of all acids (with the exception of the hydrofluoric) and nearly every other substance. It stands a considerable heat, and it' made equal ia substance and rather thin, will not easily crack by sudden alterations of tempera- ture. Without glass, microscopes, telescopes, cameras, baro- meters and thermometers — upon which some of our best and most useful knowledge and some very beautiful results of chemical action depend — could hardly have been constructed. FIG. 1. SODA-WATEK APPAEATCS. SODA-WATER. Soda-water was formerly prepared by the ordinary chemist, but since it has become so general a beverage hais been made a separate branch of chemical manufacture. Soda-water consists of a very weak solution of carbonate of soda, holding a large quantity of carbonic acid in solution, for water has the property of absorbiug a certain quantity of carbonic acid, and this quantity is increased in proportion to the pressure exerted on the water. This pressure is secured in the first place by machinery, and aftenvards maintained by the bottle being closely corked and the cork fastened in by means of wire. In fig. 1 there is an illustration of the machinery used. It consists of a small vessel holding sulphuric acid, attached to another vessel containing chalk and water kept constantly stirred by a small ■windlass passing through a hole in tlie top. and working air-tight. AVhen some of the sulphuric acid is ' 84 MAXrrACTUEED PEODUCTS. allowed to riiu into the vessel holding the chalk an effer- vescence takes place, and a rapid extrication of carbonic acid ; this is conducted by a tube to a gas-holder as a store. A tube leads from this gas-holder into a sort of air-pump, and a man, by turning a "ndndlass, not only works this and thereby forces a certain quantity of gas into another vessel of copper (plated ^^"ith silver inside), but turns this vessel itself rapidly round. In this vessel the solution of car- bonate of soda is placed, and is agitated under pressure with the carbonic acid thus forced into it, and which it rapidly absorbs. From this vessel it is drawn off into bottles, which are adroitly corked before much of PKj. 2. the carbonic acid can escape, and then wired down, a fresh supply of solution of soda and carbonic acid being constantly introduced. Potash-water and Carrara water are made in the same way, using potash in the former, and chalk in the latter, instead of soda. The form of a soda-water bottle is shown in fig. 2 ; it is made of very thick glass, that it may resist the out- ward pressure of the carbonic acid, and so formed that it cannot stand on its bottom, and when laid on its side the bubble of air shall rise up to the middle of the bottle and not to the cork, or else it would escape through the cork before Ions:, however nicelv it mav be fitted. Fig. 3 is a convenient vessel for holding about a quart of soda-water or any other effervescing drink, all of which is not at once required. A tube passes from the top to nearly the bottom of the vessel, and when this is filled with aerated water, the expansive power of the carbonic acid forces the water up this tube and out of the spout when FIG. 3. MAyUFACTlBED PEODICTS. 85 the handle is depressed and the tap opened, and when suffi- cient is obtained, the tap can be immediately closed. A very convenient apparatus called a '" &asogene " has lately been constructed. It consists of a double vessel , into the upper part of which a solution of any kind — wine and water, or even plain water — is put, to be saturated with carbonic acid or " aerated," and into the lower one some carbonate of soda and tartaric acid. A tube leads from this lower to the top of the upper vessel, which screws on and off. By shaking the apparatus when thus charged and screwed together, some of the liquid descends through the tube into the lower vessel and moistens the soda and acid, which therefore act on each other, and cause carbonic acid to be disengaged ; this, rising up through the tube (which is perforated -n-ith small holes at the upper part), disperses itself through the liquid in small bubbles, and causes suffi- cient pressure to enable the Uqixid to absorb it, which therefore effervesces when drawn off by the tap and this pressure removed. COAL-TAE yAPTlIA. This is distilled from the coal-tar produced at the gas- house, the residuum being pitch, and it has a very offensive smell. It is in demand as a solvent for India-rubber, and also for use in lamps so constructed as to require no wick, for naptha is very volatile, and the vapour is burnt as it rises. WOOD XAPTHA, OR PTROXTLIC SPIBIT. This is often called wood spirit, and is procured from the tar resulting from the distillation of wood for wood vinegar or p^Tobgneous acid. It is colorless, without the disagree- able odour of coal-tar naptha, and very inflammable, burning without smoke, very much in the manner of spirits of wine. It is used in varnish-making, and also for burning in lamps where heat and not light is required. pRODrcTs or skilled laeour. POTTEET. The art of making vessels of earth is one of the oldest of all arts ; the " potter's wheel " is frequently named in Scripture, and pottery is found ia all the remaios of ancient nations. Earthenware is made from a mixture of clay and powdered flints ; the clay is freed from all its coarser parts by being stirred with water and drawn ofl" after the gross matters have settled ; the fluid is then allowed at leisure to let fall the pure clay which was mixed with it. and is then PEODrCTS OF SKILLED LABOUR. 87 fit for use. The flints are made red-hot, and in that state thro^\■n into cold water, which makes them so brittle that tliey can be easily broken up by the " stampers," which are perpendicular pieces of iron made to rise and fall with great force ; the flints are then ground in a mill to a powder, which is treated in the same way that the clay was. "When these two earths are mixed in proper proportions, and beaten together while moist, they form a substance of the con- sistence of putty, a lump of which is thrown into the centre of a piece of board turned by means of a wheel and treadle ; wliile turning round, it is moulded by the hands into a rough outline of the si-»JLt-Ji»'=. vessel required, and afterwards put aside to dry. till it becomes of such hardness, that it can be easily turned in a common lathe, and formed into the cup, jug, or whatever else it may be intended for. This is then baked in a " kiln " or oven so contrived that it shall make it red-hot, and keep it so for about two days. If r:.iM v.iLL. ^^ jjj^g ^^ 1^^ ornamented with a design — such, for instance, as the '" willow pattern " — a number of prints on tissue paper of the subject required are kept ready, and one of these is stuck on to the vessel vdih the printed side next to the day, and rubbed smootlily on to it ; after a little time the paper is washed oti' with water, and the pattern is left on the vessel. The next process is that of glazing ; this is done by dipping the vessel into a mixture generally made of ground flints and oxide of lead made into a thin fluid with water ; when the glazing is dry the vessel is once more put into the kiln, and made red-hot. when the glazing-mixture on the surface melts into a smooth glass. Ditferent colours are given to the pattern bv mixing certain metallic substances with the ink used 88 PEODrcTs or skilled laboue. in printins;. The handles, spouts, and other projecting parts are fixed on after turning,- and before the ware is put into the kiln. ^lany kinds of pottery are not turned at all, hut made in a mould by being squeezed forcibly into it ; this is the case -when the article to be produced is octagonal, or possessed of any form not roiind, and therefore not to be produced by turninsr, and when the surface has a pattern or figures standing out in relief. Some of these are made by filling shallo'^' moulds -with the clay, and, while moist, afiixing them to the surface, but the handles of common ware are made by forcing some of the clay through a hole of the required form, 'so that it comes out in long strips or ribands, which are cut up into lengths, bent into the proper form, and stuck on to the ware, some softer clay being smeared round the joint — the whole, when baked in the kiln, becoming hard and strong. Earthenware is often made to possess some color throughout, as drab, yellow, brown, or black. These tints are produced by admixture of different kinds of clay and oxides in various proportions, oxide of iron generally giving a red or chocolate color, and oxide of manganese a drab, brown, or black color, according to the proportion used. Figures, busts, and many other articles, both for orna- ment and utility, are made of porcelain by casting, and are produced by filling hollow casts of plaster of Paris with the materials for porcelain, mixed with water to the con- sistence of cream — this is called " sHp." — and when the hollow cast is filled the porous plaster absorbs most of the moisture from the portion of liquid " slip " next to it, so that, after a time, what remains fltiid being poured out, there is found a coating or lining of porcelain mixture of considerable thickness adhering to the interior of the mould too solid to be poiu-ed out ; the whole is then set in a warm place to dry, and as the porcelain shrinks as it dries, it separates itself from the mould — which, being made of several pieces fastened together, is taken apart without injuring the cast ; after it has thoroughly dried it is baked in a kiln or furnace. This is called " Biscuit porcelain." PCG MILL. BRICKS A>D TILES. Bricks are made of clay mixed with sand or ashes. The Ijriek-field is first covered with either of these to tlie depth of an inch or two, and is well dug in and turned about during several weeks ; when the bricks are to be made, the mixture is put into a " pug mill ; " this is a large tub having an upriglit iron bar passing up from the bottom, and ha^'ing several broad iron blades hxed to its sides at the part which is in the tub ; at the top there is a cross-bar of wood, to which a horse is harnessed ; the liorse, when driven round in a circle, turns the upright iron bar and consequently the iron blades. Into this tub the clay and ashes are now put, a little at a time, and as the horse goes round they are thoroughly mixed together ; a 90 PHODrCTS OF SKILLED LABOrB. man takes pieces of this day of the proper size, and hands them to another who stands before a table in the shed, BAESow res vtet beicks. STOOL, OK WOEKIXG SHED. and has a mould before him ; this consists of a piece of wood ^ith sides of the size of the brick, which is always ten inches long, five broad, and three thick, before burning. ' The sides of this mould can be turned up and down : they are now put up. and the piece of clay forced into the mould and scraped off even at the top, the sides are put down, and the brick placed carefully on a barrow, which when filled is wheeled off' by another man, and its contents arranged on the ground in long lines ha-\'ing a small space between each brick, that they may not stick together and the air may dry them. Long rows of these bricks are formed one on the top of the other, for four or five deep, and are changed in their position from time to time till they are quite drv and hard ; thev are now readv to be burnt. This is done BAEEOW FOB DET BEICKS PRODUCTS OF SKILLED LABOUR. 91 made by placing the bricks in long rows, with narrow spaces between each row which are filled with straw or twigs of wood and cinders (these cinders are got from the ashes when they are sifted before mixing with the clay) ; the spaces beiug filled they are covered with other bricks, and then the straw, &.C., is lighted. Layer after layer of bricks are BCEXIXG BBICES. next built up around the fire, so that the heat shall be well kept in, and in this way the bricks are gradually baked till they are quite hard and fit for use. Tiles are the same as bricks, but of a different form, being flat, and having two holes iu them to receive nails. These are used to form the roofs of houses, and are nailed on to the rafters, each layer overlapping the one below it, so that the rain falling on the sloping roof shall run from the top to the bottom without coming through. Bricks have lately been made with perforations through them, which is done by haNing a mould with a number of iron rods projecting from its bottom, so that when the clay is forced on them they pass right through it, and leave holes. The objects gained by this are two ; in the first place, the bricks are much lighter, a great advantage in building, and 92 PEODrCTS OF SKILLED LABOrE. in the second place they do not get so much out of fonn in burning, as there is no great substance between the holes, and therefore the shrinking takes place more evenly. Most of these bricks are of a light straw color, and are used for MIXING CHAXK facing. They are mixed with a quantity of chalk, which is worked up with the clay, and are not baked at such a heat as would burn it into lime. TOBACCO-PIPES. Tobacco-pipes are made of a fine white clay, found chiefly in the island of Purbeck, and called, from its use, pipe-clay. Dr. TJre gives the follo-rtdng account of the manufacture of tobacco-pipes : — " A child fashions a ball of clay from the heap, rolls it out into a slender cylinder upon a plank, with the palms of his hands, in order to form the stem of the pipe. He sticks a lump at the end of the cylinder, for forming the bowl ; which, having done, he lays the piece aside for a day or two to get more consistence. In pro- portion as he makes these rough figures, he arranges them by dozens on a board, and hands them to the pipe-maker. The pipe is finished by means of a folding brass or iron mould, channelled inside of the shape of the stem and the bowl, and capable of being opened at the two ends. It is formed of two pieces, each hoUowed out like a half pipe cut as it were lengthmse, and these two jaws when brought PRODUCTS OF SKILLED LABOUR. 93 together coustitute the exact space for making one pipe ; there are small pins in one side of the mould, corresponding to holes in the other, which serve as guides for applying the two together with precision. The workman takes a long iron wire, with its end oiled, and pushes it through the soft clay in the direction of the stem, to form the bore, and he directs the wire by feeling with his left hand the progress of the point. lie lays the pipe in the groove of one of the jaws of the mould, with the wire sticking in it, applies the other jaw, brings them smartly together, and unites them by a clamp or vice, which produces the external form ; a lever is now brought down, which presses an oiled stopper into the bowl of the pipe Avhile it is in the mould, forcing it sufficiently down to form the ca\-ity, the wire in the mean- while being thrust backwards and" forwards, so as to pierce the tube completely through ; the wire must become \'isible at the bottom of the bowl, other%vise the pipe will be 94 PEODrcTs or skilled LABorn. imperfect. The "«^re is no\r witlidrawn, the jaws of the mould opened, the pipe taken out, and the redundant clay removed with a knife ; after dr_\-in2; for a day or two, the pipes are scraped, polished with a piece of hard wood, and, the stems being bent into the desired form, they are earned to the baking kiln, which is capable of firing fifty grross in from eight to twelve hours. A workman and a child can easily make five gross of pipes in a day." The pipes known as " meerschaum " are cut and shaped out of a natural earth or mineral, found chiefly in the island of Samos ; it is not a clay, but consists of silica, magnesia, and lime, and is therefore a kind of magnesian Hmestone. It is nearly white, very light and porous, is easily exit with a knife, and bears a beautiful polish when saturated with the oil of the tobacco, which at the same time gives to the pipes a rich dark-brown color. The meerschaimi pipes sold in London are saturated \iith wax or grease, to cause them to color more easily, and many are not meerschaiun at all. but are made of the diist produced in the cutting and boring of the real meerschaum pipes, mixed up with size ; these fictitious pipes are heavier and less porous than the true meerschaimi pipes, and neither color so readily nor bear so beautiful a polish ; they are, moreover, much more easily broken. GOLD-LEAF. For the purpose of gilding very thin leaves of gold are required, so thin, that although gold is expensive, yet gilded articles (as picture-frames) are very far from being so. To produce this gold-leaf is the business of the gold- beater. He first obtains the gold in a state of purity from the refiner, in the form of small grains, which, mixed vrith a small quantity of borax and alloy, are put into an earthen pot called a crucible (coated beforehand with clay to keep it from cracking), and then placed in a furnace which is raised to a white heat. The gold, when melted, is poured into an iron mould made warm and greased in the inside ; PROBrCTS OF SKILLED LABOfR. 95 this when cold forms an " ingot," Avhich weighs two ounces, and is three-quarters of an inch square and not quite half- an-inch thick. Tliis ingot is now sent to the " flattening mills," where it is passed between sets of steel rollers until it is rolled out into a sort of riband an inch wide and about twelve feet long (at this degree of thinness a square inch will weigh six-and-a-half grains). It is now cut into 150 pieces, each an inch square, which are packed between pieces of vellum, four inches each way, and surrounded by a sort of bag of the same material, the whole being then subjected to tlie blows of a heavy iron hammer (weighing about foiu-teen pounds) upon a block of solid stone, till the plates of gold are beaten out nearly as large as the vellum, when they are taken out and each cut into four pieces. These quarters are treated as before, using gold-beater's skin " instead of vellum (this skin is prepared from the intestines of the ox, and a set of these, consisting of several hundreds, is called a " mould "), and the gold again extended under the hammer to the size of the mould. The process is repeated in the same manner a third time, after which the leaves of gold are taken out, cut square on a cushion ot leather, lilted carefully by means of a sort of tongs made of wood, and placed in the book. They are now between GOO and 700 times thinner than before the beating com- menced, and it would take about 280,000 of these leaves to make the thickness of an inch. The leaves are from three to three-and-a-half inches square, and are packed in books of paper having the surface of the leaves rubbed with red chalk, to prevent them from adhering to the gold ; each book contains twenty-five leaves of gold. The ditferent colors of gold-leaf, such as " pale gold," " deep gold," or " red gold," are produced by a small alloy of copper or silver, the former gi\'ing a deeper and the latter a paler tinge to the pure gold. A certain amount of alloy is always mixed with the pure metal, otherwise it would adhere to the moidd, and would not work so well. SHOT. Shot are made eitlier of iron or lead. All shot for g^reat guns or cannon are made of iron, but for small-arms leaden balls are used, which are cast to fit the bore of the weapon. For sporting purposes small shot are made, of different sizes ; they consist of globules of lead -nrith a small pro- portion of arsenic mixed with it — the object of mixing arsenic is to make the shot divide better, as it has been found by experience that lead alone does not divide so well — this mixture, while in a fluid state, is poured through a colander or sieve made of iron and ha\"ing the bottom perforated with small holes, to suit the size of the shot to be made. These colanders are placed at the top of PKODUCTS OF SKILLED LABOUR. 97 a high building like a tower, aud the melted metal runs through the perforations in fine streams and separates into single drops as it falls. At the bottom of the building the shots are received in vessels of y i :-'~) water, to cool them. In these vessels all ^ the little globules are not exactly of the same <;' size, although the holes in the colanders s SIEVE FOE MAKING SHOT. regulate this to a certain extent, more- over they are not all round ; they have, therefore, to be sorted, which is done by placing the shot by handfuls upon a board slightly tilted, so that the round ones roll to the bottom aud are received in a box, those that are crooked, &c., lag behind on the board, and are put aside to be re-melted. The shot in the box have next to be sorted as to size ; this is done by means of two sieves ; the holes of one sieve are a little larger than the size of the shot required, and this retains therefore all that are too large, the next has holes a little less than the shot, and this retains the right t^ize and lets aU the shot that are too small pass through ; by these simple means the shot are separated into many sizes, which are numbered. The shot have now to be finished, which is done by turning them, mixed with a little black-lead, in a sort of barrel, which gives them a beautiful black shining surtace, and rubs off any roughness. SECTION OF SHOT- TOWEB. FILE CUIII^G. FILES. Files are among the most useful of tools for those who work in metals, and in many other substances, as ivory, or hard woods. A file consists of a bar of steel of various shapes, such as flat, square, three-cornered, round, and half-round ; on the surface of this bar of steel small furrows are formed, with rough projections between them, and these are again, in most kinds of files, crossed with others. The mode of making a file is as follows : — A bar of wrought or cast steel is cut off" of the requisite length and of the proper figure, and forged on an anvil to the required shape — that is to say, rather tapering at the top and brought to a point (called the " tang ") at PBODUCTS OF SKILLED LABOIE. 99 the bottom, so that it may be driven into a wooden handle. The file has now to be cut. To do this requires great manual dexterity. A man sits before a bench, and passes a strap over each end of the file so as to steady it, and these are kept down with the feet. A small chisel of hard steel is held in the left baud between the thumb and finger and struck with a short-handled heavy hammer, the efiect is to cut a notch, with an elevation at each side called a " burr ; " — '"^ the small chisel is slipped up to this "burr," and struck again, and so on till the whole file is cut, and this with such rapidity that the eye can scarcely follow it. WTieu the file is thus notched from end to end, it has to be hardened, which is done by making it red-hot and suddenly plunging it into cold water, which makes it so hard that it will scratch glass and cut away any other metal. For softer substances, such as wood, a kind of file is often used called a " rasp," which, instead of having furrows ^^mmemm*.^ cut on it, is struck into little dints by means of a three- cornered piece of hard steel, which, as it enters the file, throws up a projection also. For filing bone and ivor^'. a kind of file is used with ver)' large notches, not crossed by others, the edge of each of which acts like a plane-iron or chisel, and takes off shavings from the bone. TYPE. Tlie casting of types for priuting is for the most part done by hand, and singly, and it is one of those arts iu which u 2 100 PKODUCTS OF SKILLED LABOrR. extreme dexterity (only to be acquired by incessant prac- tice) enables the founder to accomplish an amount of labour which would seem to any one not witnessing the process impossible. To cast each piece of type it is necessary to dip a little ladle into a pot of melted metal, to fill the TYPE CASTING. mould, give it a sudden jerk with the left hand so as to make tlie melted metal go well into the little moidd, open the mould and take the type out, shut up the mould and fasten it, and yet a skilfid workman can perform these operations five hundred times in an hour — that is to say, rather more tlian eight times in a minute — producing a type each time ; this has aftenvards to be finished off" by others. The metal of which type is made consists of lead and anti- mony — the antimony hardens it and makes it take a sharper PRODUCTS OP SKILLED L.VBOrR. 101 impression. The letters are first cut in steel, and from these " dies " the moulds are made in brass, by stamping, and in these the types are cast. Stereot\-pe consists of plates of metal taken, by casting, from a forme of type set up for the purpose ; an impression in planter of Paris is first taken, and from this the metal impression is cast, so that the original forme of type may be " distributed " or taken to pieces, and again used, while the stereotyped impression can be preserved for any fixture printing. FILLING TDK BOXES. LUCIFER-MATCHES. These convenient matches, which have completely super- seded the old apparatus of Hint, steel, and tinder-box, niay be looked upon as one of the improvements derived from chemistry, for phosphorus — the necessary ingredient — till lately sold at half-a-crown an ounce ; such a price would, of course, prevent its being used for so general a purpose as match-making. But when chemistry devised means of 102 PKODrCTS or skilled LABOrR. preparing it on a large scale, and at a low price, then its application was soon perceived. Some years ago a kind of match was used, made of chlo- rate of potash and sulphnret of antimony, and ignited by drawing through a folded piece of glass-paper. Another sort was also for a time in use called " Prometheaus," but far too expensive for general use. They consisted of strips of paper rolled up, with a little glass cylinder full of sulphuric acid sealed iip in the end of each, surrounded by chlorate of potash in powder ; the end of the match had to be crushed by a small pair of nippers, and the glass being broken, the sulphuric acid came in contact with the chlorate of potash, causing it to take fire. For making lucifer-matches the wood is sometimes split by hand, and sometimes by machinery. For those the wood of which is roimded, a peculiar apparatus is used ; it CUTTING THE MATCHES. consists of a plate having small steel cylmders let into it, so that their cutting edges are raised above the plate, and the Avood is struck upon this, and not only divided, but each piece forced through the cylinders and so rounded. When cut, the wood is dipped in bundles into melted sulphur, and PRODICTS OF SKILLED LABOVB. 103 afterwards into a composition variously made, but usually consisting of phosphorus ground up with gum arabic and water, colored either with red-lead or Prussian blue, and in FILLING TIIB FKAiU;. DIPPIXu lUi some cases clilorate of potash is added. This composition is spread out on a board to about the tenth of an inch in thickness, and the matches which have been dipped in sidphur are packed into a frame to the niunber of about 3(X>0, and dipped by pressing them on the board spread ^^'ith the composition, so that a little is attached to the ends of each match. This is a most un- wholesome and dangerous em- ployment, and water is always at hand, in case of fire, which is chiefly to be feared in the ysAiLb. process of separating them and filling the boxes when the composition has dried. CAMtLE MANUrACTOKT. CAXDLES. Candles are made of either wax, spermaceti, stearine, or tallow, or some compound or modification of these ; but of whatever they may be made, they are formed either by dipping or casting, and hence the names " dips " and " moulds." When dips are to be made, a quantity of wicks of spun cotton are prepared by a machine, and doubled so as to form a loop at the top, through which a stick is passed. A mmiber of wicks are arranged in a line on each stick, and several sticks placed side by side on a frame, which is attached to one end of a balance beam (called by the work- men the "Horse's Head"), with weights at the other end, according to the weight of the candles to be made. The frame, with the -ndcks upon it, is suspended over a cistern of melted tallow (kept warm by a small fire or flue), into which it is lowered, so that the wicks dip into the tallow ; this is repeated two or three times, till a coating of PBODUCTS OF SKILLED LABOUR. 10'5 tallow is formed on the wicks, which, are then placed aside CUIT1S& THE VTICKS., to cool while others are served in the same way, and so on, over and over again, till each frame weighs enough -■*^ UOUSE S UE.VD. moLlMf FHAME. to exactly counterpoise the weight at the other end of the beam. 106 PEODVCTS OF SKILLED LABOUE. Mould candles are made by pouring melted tallow into a wooden trough in the bottom of Avhich pewter moulds, of the size of the candles required, are fixed in such a way that they open into the trough by the ends which correspond to CAMiLE-MOL'LDS. the bottoms of the candles to be cast in them. The other end of the mould is brought to a point, with a small hole in it, through which the wick is passed and fastened to a stick running along the moulds ; and as the moulds are placed in two lines, two sticks are sufficient for the trough. Melted tallow or spermaceti is poured into the trough, and when coid the superfluous quantity removed, and the candles dra'wn out of the moulds. "Wax candles are made by pouring melted wax doAvn the ■s\-ick till sufficient has adhered to it, then roUing the candle on a marble slab till it is even, and afterwards polishing with a cloth. EOPE Is a combination of the fibres of hemp or other material, so arranged as to form a tenacious cord or band, retaining, as far as possible, their collective strength. The first pro- cess in rope-making consists in twisting the hemp into thick threads, called rope-yarns. This, which resembles ordinary spinning, is commonly performed by hand, in a rope-ground SPIXSIXG TUB YAKN. or rope-walk, an enclosed level piece of ground, about six hundred feet in length, at one end of which a spinning- sri.N.M.Nu-\VHI.EI.. wheel is set up, that gives motion by a band to several small rollers or " whirls," each of them furnished with a hook on 108 PRODUCTS OF SKILLED LABOI'E. tlie end of its axis next the walk. The rope spinner cari'ies a bundle of hemp about three feet long round his waist, with the fibres all laid even, and having their ends in front of him, and from these he pulls out sutEcient for the thickness of the " yarn " he is spinning, and after slightly twisting it with his fingers, attaches it to the hook of a "whirl," which is set in motion by the wheel, and as the fibres are twisted he walks backward, gradually adding more and more, a little at a time, so as to keep the yarn of the same thickness throughout. A\'hen the spinner has traversed the whole length of the rope-walk, he stops, and another spinner detaches the yam from the whirl, and it is then wound on a reel or bobbin. The yarns being spun, they are next "tarred" (if they are to be much exposed to wet, as for the rigging of ships), which is done by di'awing them through a kettle full of melted tar. being wound otf from one reel on to another, and the superfluous tar A^dped away by means of tow (rough hemp) fixed in a hole through which they are drawn. AVhat is called " laying " the rope consists in twisting a certain number of yams together, so as to form a strand, HA\VSEE-LAID EOPE. CABLE-LAID EOPE. and these strands into a rope. Large ropes are chiefly of two kinds, called respectively '• hawser-laid " and " cable- hiid," the latter including only the very largest ropes. " Hawser-laid " ropes consist of a certain number of yarns (according to the size of the rope) twisted into a strand, PBODrCTS OF SKILLED LABOUE. 109 and then three of these strands twisted together. The '' cable-laid " rope is composed of nine strand^, that is to say, three strands each composed of three others, and these composed of yams, so that three " hawser-laid *' ropes, twisted together, would make one '' cable-laid " rope. Laying the ropes and twisting the yams into stmnds are both accomplished by the same process. The yams are attached — in sufficient quantity for the strands — to three hooks, each turning in the same direction, while the other ends are collected together and turned in the opposite direction ; the three hooks twist the yams into strands, and a hook at the other end twists the strands into rope. £OFE-VA£I5G BY MACIU>'£KY. Of course, machinery of various descriptions ha^ been applied to rope-making, and ropes are frequently made entirely by machinery with great rapidity. The annexed cut represents one mode of rope-making by machinery, in which the yarn is shown being twisted into cord or rof>e from the reels or bobbins on which it was wound after spinning. COAESE WIKE DKA\VI^G. WIEE. In the manufacture of wire, the metal from which it is to be made is first cast or wrought into an ingot (a, tig. 1) ; it i s then passed between rollers (fig. 2) which flatten it into a sheet (b, fig. 1), which is next carried between other rollers (fig. 3) having their surfaces so cut that the projections on PnODUCTS OF SKILLED LABOUR. Ill cue of them fit into the hollows of the other, forming so many cutting edges or shears (fig. 4), from which the sheet LaJ L FIG. 2. FHi. o. of metal comes forth at a, fig. 3, cut into strips or square rods (Cjfig.l). These rods are then drawn Avith great force through a plate of hardened steel haWng a series of lioles, gradually diminishing in size, bor tlirough it, which is called the "draw-plate the wire (of whatever metal it be) has to be heated red-hot from time to time, to soften or "anneal" it, for the compression pro- duced by the drawing so hardens it that it becomes brittle. A pair of nippers holds the end of the wire, and these are moved along a sort of bench by a "■ rack and pinion " (fig. 5). "WTien all has passed the first hole, it is drawn through the second, and so on to the size required. AV^hen the wire is pretty fine, it is attached to a "cylinder," ^^"' *" wliich on turning round winds oft" the wire and at the same 112 PEODrCTS OF SKILLED LABOrE. time draws it through the plate, as shown in the engraving, the wire being made to pass over a small charcoal fire previous to entering the draw-plate. rf4"~r-T--r^ ;^^. Different metals have different powers of " ductility," that is to say, some can be drawn much finer than others. Dr. Ttu'ner says, " The only metals remarkable in this respect are gold, silver, platinum, iron, and copper. AValliston devised a method by which gold wire may be obtained so fine that its diameter shall be only the 5000th part of an inch, and 550 feet of it are required to weigh one grain ; he obtained a platinum wire so small that its dia- meter did not exceed the 30.000th of an inch. It is singiilar that the ductility and malleability of the same metal are not always in proportion to each other. Iron, for PRODUCTS OF SKILLED LA.BOrE. 113 example, cannot be made into thin leaves, but it may be drawn into very small wires." The sizes of wires are ascertained by a small instrument called a "gauge," which is a plate of steel with an openiug -j «j loj ^ in| «:^ r^^j ooj o>| o| 1 M 1 1 1 1 I 1 1 FIG. 6. diminishing to a point in it, and marks on the sides corresponding to the distance the wire vnil pass down the notch (fig. 6). CUTLEET. Table cutlery is made in the following way. The blade is fii'st rudely fashioned from a flat bar of steel by the hammer and anvil, and this is then welded to a bar of soft iron half-an-iuch square, and cut off, leaving sufficient to form the •• shoulder" or "bolster," a, and the "tang," b, fig. 1, ^ PIG. 1. which is first made by the hammer and then beaten into a sort of mould or die. The blade is fijiished as far as can be done with the hammer, made red-hot, and thrown into cold water, which hardens tlie steel, and then " tempered " to a full blue color (see "Steel") after wliich it is fit for grinding. Eazors and penknife-blades are made of fine steel, and are forged and hardened as above, but the tempering is effected by arranging them in rows with their backs dowTiwards on a plate of hot iron till the color appears on their surface indicating the temper they have received, which for razors is a pale straw color. Cutlery is ground upon stones of different sizes, according to the kind of article ; for saws, and table-knives, which are I 114 PEODrCTS OP SKILLED LABOrE. to be ground to a flat surface, very large stones are used, while razors, -vs-hieh have a curved surface, and penknives, whose blades are very narrow, are sround upon ven^ small stones. These stones are driven by machinery with great rapidity, and are arranged over a trough of water, so that their lower parts dip into it, by which plan the stone is kept wet : if it were used dry, the steel would get too hot to hold, and the temper of it be injured. The article to be ground is held at the top of the stone. ~When ground, the goods are " glazed " by means of a wooden wheel the edge of which is smeared with emery -powder, and finally, if they are to be pohshed (which is only in the case of the finest steel instruments), they are held to the edge of a wooden wheel covered with bnff-leather, and charged with " crocus " — this crocus is a red oxide of iron much used for polishing all sorts of things, as it is both fine, free from grit, and sufficiently hard. "UTiat are called " balance-handle " table-knives are those which when laid on the table, will rest with the blade elevated so as not to touch the cloth (fig. 2). The object sought in this arrans:ement, is to keep the cloth from being soiled, and the manner of attainins: it is simply by making the shoulder project a little and running a small quantitT.- of lead into the hole of the handle before the '' tang " of the knife is introduced. The blade and handle or " haft " are united by means of rosin, which is put in powder into the hollow of the handle, and the tang, being made hot, is forced in, melting the rosin, and fixing when cool. >'AILS. Xails are made both by hand and machinery, the former being called "wrouo;ht," and the latter " cut" nails. For making nails by hand, a hammer and an anvil only are used. CUTTIXG THE METAi IXTO SLIPS. The "nailor," having put several rods of iron of the required size into the fire to get hot, that he may use one after the other, and so lose no time, takes one out and with the hammer beats it to a point, leaving a little shoulder (fig. 1). Fiq.2 He then places it (at the part where the dotted line is in I 2 116 PEODUCTS OF SKILLED LABOrE. the figure) on a wedge fixed to the anvil, and with a blow of the hammer divides it ; it is taken up by tongs, dropped into a hole in the anvil, and the shoulder beaten flat ; this is called a " tack " (fig. 2), for a " clasp nail " the head is made of a diflerent form by a particular way of striking it (fig. 3), and the form of the hole in the anvil determines whether they shall be square or round ; -RTought " brads " have the form of fig. 4. These are the principal forms of nails, but many others are made by soldering shanks to cast Cl"TII>-(i BEADS. heads, as coffin-nails, and some (chiefly used by gardeners and plasterers for driving into brickwork) are made of cast- iron. Machine-made nails are cut by compression from a sheet of iron. Brads are cut out, simply, as in fig. 5, which uses up the whole of the iron without any waste, and requires no finishing ; but other forms of nails are cut first into simple wedges, and have the heads finished afterwards either by the blows of a hammer or by compression. PRODUCTS OF SKILLED LABOUli. 117 Most nails are made flat or chisel-sliaped at the poiut, that they may not split the wood. In driving a nail with a flat point, the length of the point should be placed across the grain of the wood, and then it will hardly ever split it, but if otlierwise, the nail, acting as a wedge, opens the grain and splits the wood. SCREWS. The screws used by carpenters, smiths, and others, for fastening wood or metal-work together, are generally made by machinery. A piece of wii-e of the required thickness aiid length is first cut oft', which is then placed in a hole or mould, with its upper orifice " countersunk " as in the annexed cut, and the head of the screw is formed by beating the upper part of the piece of "«-ire into tlie counter-sinking of the mould. It is then called a " blank," and a number of these blanks are dropped into holes bored round the periphery of a wlicel which revolves slovrly against a small circular saw driven with great rapidity, and cutting a "thread " or slit in the head of each blank in turn as it comes into contact with it ; the Avheel continuing to revolve, each screw wlieu it gets to the bottom drops out, so that the holes when tiiey again arrive upwards are ready to receive fresh blanks. The worm, if cut by liand, is made by means of a die of hard steel, having a hollow screw cut in it, which is screwed slowly by a backward and forward movement on to the blank, cutting it into a " worm ; " when tliis is done by machinery, the die is lield fast while the screw is worked by a rotatory movement into it. The best screws for wood are slightly tapered, which enables them to be driven much more easily, Avhile they hold equally fast. Large screws for mechanical purposes are cut by a ''lathe," the bar revolving whilst a cutter is hekl to it, and moved onwards by a pattei-u screw. Small screws for various purposes can be easily cut by means of a " screw- plate," having lioles of graduated sizes cut inside into liollow screws, whicli is phiced on the end of the wire, and gently turned round till it is sulliciently cut. PIX-ilAKING MACm>E. Piiis are made from brass wire drawn out in the usual mamier (see "Wire-drawing"). It is first straightened and then cut ofl" into lengths sufficient for two pins ; these are pointed at each end b}' holding them to a wheel, about two or three dozen at a tune, turning them all round at once by means of the thumb and fingers. The wheel is not made of stone, but of steel, having the edge cut into fine notches like a file (see "File-cutting"). After the ■«'ires are pointed at each end, they are cut in the middle. The heads are made by coiling some brass wire round another piece of wire exactly the size of the pins for which they are intended, aud with a sort of chisel cutting oft" two of these coils at a time. The accompanying figure represents the coil to be cut up into a string of heads, and one of them separate. Tiiese are fixed on to the pointed wires by a machine acting by means of a lever, by which they are compressed into PEODUCTS OF SKILLED LABOUB. 119 the right shape and at the same time made to hold oa tightly. The pins are then cleaned by boiling in some weak acid or a solution of tartar, and have next to be "tinned " or " whitened," which is done by placing them in layers with grain-tin and cream of tartar, and boiling them for some time till they are coated Avith the tin ; thus they are truly "electro-plated," although at the time when this process was invented no knowledge of electro-plating existed, and the theory of the process was not understood. The pins are afterwards cleaned and brightened by shaking ^ COIL FOE THE HEADS. them in leather bags with bran, which is afterwards blown away by a blowing-machine ; the pins are then placed in papers (folded by a sort of crimping-machine), which are put into a kind of vice, haA"ing a number of notches cut in it corresponding to the number of pins to be stuck in one row, and into these notches and througli the paper ridges the pins are rapidly passed by children. In some manufactories pins are made entirely by ma- chinery, and these are the " solid-headed pins," or pins which have the head formed out of the same piece of wire as the body, which is chiefly efiected by compression, and in order that this may be readily done, the wires are prenously softened by heat, which is one of the principal objections to their general use, as, in consequence of this softening, they bend too readily. >\XN?*^;5V- DEILIIXG THE ZTES. >'EEDLES. The manufacture of needles is one of those arts in which manual dexterity is acquired by minute subdivision of labour, each artisan perforaiing only a small part of the process, but so often, that the most -wonderful rapidity and accuracy are obtained, insomuch that although each needle has to pass through nearly 150 hands (together -with expensive machinery) before finishing, yet they may be bought at an astonishingly low price. The following is an outhne of the process of manufacture. The wire is first selected, of the best steel and of a proper size, then wound round a cylinder some fifty times, and the coil is cut in two places opposite to each other through all the wires. These wires are placed together in bundles several feet long, each containing about a hundred wires, which are then cut up into lengths sufficient for tft-o needles by a pair of shears worked by powerful machinery. As the PEODUCTS OF SKILLED LABOUR. 121 wires are crooked, they have to be straightened, which is done by packing them in bundles and enclosing them in two iron rings so that they may be rolled forcibly backwards and forwards between steel plates with grooves cut in them to receive the projecting rings, and this straightens them thoroughly. The wires are next ground to a point at each end by holding them, a dozen or two at a time, against a revolving stone, to which they are pressed with a piece of leather, at the same time turning or irwirling them between the thumb and lingers ; when pointed, they are cut in two by a gauge which divides them in the middle, and the blunt ends are spread out in the form of a fan on a small anvil by the thumb and finger of the left hand, several at one time, and flattened by the blow of a small hammer. This flattening makes the ends too hard for piercing, so that they have to be softened by being made red-hot and slowly cooled ; they are then pierced by children, who lay each needle on a piece of lead and with a small punch and hammer strike out the eye, but in nearly all cases the eye is drilled, in which case the wire is held for an instant to the point of a small drill turned by machinery. The groove which leads to the eye is made either by the stroke of a small file or by compression, and the end is next rounded off. In some needles the eyes and grooves are made by punching two in the middle of a wire, which is afterwards divided. The needles are tempered, by placing some thousands of them on an iron plate which is made red-hot, and then throAving them suddenly into a vessel of cold water ; they are by this means made too hard, and have again to be slightly heated to give the proper degree of temper and toughness (see " Steel "), which is done by putting them in 122 PEODrCTS OF SKILLED LAEOrE. boiling oil. They have nert to be polished, and this is the most tedious part of their manufacture. The needles, to the number of about a hundred thousand, are packed, together with oil and emerv-powder, in a strong sort of bag, so that ther aU lie side by side, and several of these bags or bundles are rolled backwards and forwards between wooden beams in such a way that every needle rubs against others, and the friction thus produced grinds them bright and smooth. After a time they are taken out, and the black paste formed by the emery -powder, oil, and steeL is cleaned off by putting them into saw-dust, and turning them in a barrel fixed in a frame for the purpose ; the saw-dust and dirt are then blown away by a blowing-machine, and the needles again undergo the same process several times, using finer emery -powder each time, so as to polish them ; after which they are scoured with soap and water and wiped dry by rolling them in dry wash- leather. They are now perfectly bright, every roughness rubbed off. and a finish being finally given to the points by hand on a hone which turns round, they are packed, twenty- five in each paper, for sale. TUBIXG. Tubes of lead and brass are cast in short and thick pieces, and then drawn through holes in a draw-plate, similarly to wire, but bavins; a rod or "mandril" passed through the length of the tube to keep the hoUow of the right calibre. I■SA^v:v,J. Iron tubing for gas and water pipes, if more than about two inches in diameter, is cast : but smaller, or '• service-pipes." are made of wrought iron plate rolled on a mandril, and welded at the edges by being drawn at a white heat through a draw-pkte. STEEL PEXS. Steel pens, which have almost superseded quill pens, are made in great quantities, and, like needles and pins, can only be produced at a sufficiently low price to meet the requirements of the people, by those who have erected buildings and fitted up machinery so as to make the process sufficiently rapid to be cheap. The steel is first selected of the proper quality, and roUed out into sheets of the thick- ness required and of breadth sufficient for the length of the pens to be made ; these are punched out of the proper shape bv a punch worked by a screw, which cuts out a piece at ever)- blow, and also the perforation which terminates the split. The maker's name or any other deWce is stamped on this flat piece of steel, called a •' blank," which is then. 124 PEODUCTS or SKILLED LABOrR. coiled up into tlie shape required (-n-liether a " barrel " pen or a " nib ") by a sort of press, worked hy a girl, as seen in the engraving, and the split made by a machine, also engraved. In both these machines the screw is worked with the left hand, while the right is engaged in placing the pens under it and pushing out the pen with the finger after it is bent or slit, these operations, from constant practice, being performed with great rapidity. The pens have next to be STAilPISG TUB PEX FEOil THE STEEL. tempered, by being made red-hot and then tlirown into water or oil, and are afterwards polished by putting them into a barrel with fine sand, which is turned round by a windlass for several hours. The nibs or points are then fijiished at a stone which turns roiuad, and a varnish of a brown color — made by dissolviug shellac and asphaltum in naptha — is given to the siu'iace to keep them from rusting. PEODUCTS OF SKILLED LABOUB. 125 Sometimes the surface is "blued," whicli is done by heating the pens on an iron plate till the blue color appears (see "Steel"). BBXDIXG IILE PEX. Pens are sometimes made of other metals besides steel, as brass, or zinc, and sometimes of gold. Those made of gold are, of course, too expensive for general use, but as they are never corroded by the ink, they last a ver^' long time, and can always be cleaned by washing ; and as the whole wear is at the point, this is tipped with an alloy which is exceedingly hard. ARTS A.\D TRADE PROCESSES. Wv-i' ln(j:.a% "WOOD AND PLATE EXGEATIXG. Engraving consists principally of two kinds, that in wliicli the design is made to project, and that in which it is cut in or indented ; the first kind is used in wood engra^Tiig, and in engraving metallic or wooden blocks and cylinders for cahco printing, the other is called "plate engra-sTUg," and is used to produce copper, steel, and zinc plates for printing. In wood engraving a block of box wood is used, or several pieces are screwed or tongued together in order to make a block of the required size, for the box wood must be cut ARTS AND TEADE PROCESSES. 127 across the grain, therefore large blocks are not easily pro- cured. These blocks are about an inch in thickness, so that they may range with type and be printed with it, they are made perfectly smooth on the face, which is rubbed with a little Hake-white and Bath brick, to give it a whitish and slightly roughened surfoce. On this prepared surface the design is drawni vnth a black-lead pencil, and the block is then put into the hands of the engraver, Avho cuts away — to the depth of about one-twentieth of an inch — all those parts which have not been blackened by the pencil, leaving every line and dot of the dra\\"ing projecting, and this serves as a sort of stamp or type, to print from. (See "Printing.") In this way the illustrations to the present work are produced. In plate engraving the design is copied from the original and cut into the plate in a manner quite opposite to that of engra^■ing on wood ; for every line intended to be printed, instead of projecting, is cut in with a sharp edge, so that they may be filled with ink, instead of being covered, as in wood engraving. When the design is formed entirely by lines, it is called " line engraving," and Avhen formed by dots, it is said to be " stippled," and these two kinds are often com- bined in the same plate. There is a process for engraving plates, called "etching," by which the lines or dots on the plate are not made by cutting, but are corroded or eaten in by the chemical action of nitric acid ; and few plates are now produced by the graver alone, the design being first etched and afterwards finished ofi' by the graver, but some are pro- duced by etching alone, whence they are called " etchings." The process of etching is as follows : — The surface of the plate is made smooth and bright, then heated, and after- wards coated with a mixture of asphaltum, wax, and mastic — called "etching-ground " — a ball of which is tied up in a piece of silk, rubbed over the hot plate, and dabbed with a dabber till a smooth layer or coatmg is formed all over it ; it is " smoked " over the flame of a candle, to blacken it, and the result is a smooth black varnish, which covers the surface of the plate, and is capable of resisting the action of nitric acid. On this surface the design is drawn with an " etching-point," a steel instrument which cuts or scratches 128 ARTS AND TRADE PROCESSES. quite through the etching-ground, exposing the surface of the copper at the bottom of each scratch. "When the design is finished — in lines or dots, according to the style required — a ridge or border of wax is made all round the plate so as to form it into a sort of shallow tray, and into this the nitric acid, mixed -R-ith a little water, is poured, and carefully watched till in the judgment of the engraver it has bitten into the plate sufficiently for the fainter parts of the design. The acid is then poured off, and the plate washed and dried, after which the parts intended to remain most lightly etched are stopped out with varnish, and the acid again poured on, to corrode the lines left exposed to its action more deeply. This is repeated two or three times, according to the nature of the design, when the plate is again heated, to melt the etching-ground, and the whole is cleaned off with turpentine. The plate may now be used to print from, or it may be frirther finished by the " graver," " biu-nisher," or " dry point," which is simply a point of steel used to make very fine and faint scratches instead of cuts, for the graver cuts out the piece of copper, while the dry point merely indents it. There is another kind of plate engraving, called " mezzo- tinto." This is done by first covering the whole plate with a rough granulated surface — called a "mezzo-tint groimd," — by means of a sort of notched chisel, called a " cradle " or " grounding-tool," which is rocked to and fro over the surface in every possible direction, tUl the whole is covered with minute dots ; so that if it were then used to print from, it would produce an even dark surface. On this groimd the engraver works with a " scraper," scraping gradually away all those parts which are to appear as lights in the finished picture, and the more the groimd is scraped away the lighter will be the tint, till, finally, those parts which are to be quite white are scraped smooth and burnished, so that they shall hold no ink at aU. In this way the engraver proceeds till his design is finished, trjang the effect from time to time. This kind of engraving is often combined with etching, producing greater sharpness of outline than mezzotint alone. HTUOGLAPlllC PKESS. LIXnOGEAPHT. This is the art of producing designs upon stone in such a manner that impressions may be printed from them. It is often miscalled " engraving on stone ; " properly speaking, it is not engranug, but a process depending on the want of affinity between watery and greasy matters, the design being made with a greasy substance, either in the form of ink or crayon called '' lithographic chalk," as follows. A close- grained stone called lithographic stone (a kind of magnesian limestone) is ground perfectly even on the surface, and (if for being written upon) polished with pumice-stone, or (if for being drawn upon with chalk) gi'ained with line sand ; the design is drawn with chalk or ink, each of which is made up of greasy materials — wax, soap, and asphaltum, colored with lamp-black. AVlien the design is made, the stone is etched — washed over with a weak mixture of nitric acid and water — which answers three purposes ; it very slightly bites away the stone in all places except where it is covered with the ink or chalk, it smoothes the grain iu the same places, and it converts the soap 130 ARTS AKD TRADE PROCESSES. of the ink or chalk into grease. "We have now the surface of the stone quite wet, except where the design is, which, being greasy, keeps quite dry. The stone, placed ia a press, is rolled over with a roller smeared with greasy printing ink, which will not adhere to the wet stone, but it readily does to all parts of the design ; a piece of paper is placed over the stone, and a ilap of leather covers it; along this leather the scraper of the press is brought very forcibly when it is Avorked, and on removing the paper an impression is foimd to be transferred to it from the stone. This process is repeated agaiu and agaia, many himdred times, without much injury to the origiual design. Colored lithography, called chromo-lithography, is pro- duced by using several stones consecutively (each trans- ferring a separate color), so that the design shall be complete when the whole are printed. PRIJiTTING. The art of printing consists in producing impressions from a pattern or types — cut out and projecting, or engraved and indented — by smearing the projecting parts or filling up the indented markings with ink, so that impressions, to any number, and exactly resembling each other, may be taken from them. Printing is comparatively a modem invention, although impressing or taking imjjressions from seals is one of the very oldest. It is divided into two kinds, plate- printing and surface-printing. Printing from t}^e or blocks having the marks to be impressed raised, is called surface- printing, while that in which the lines or marks are cut in, is called plate-printing. In surface-printing, when types are used, they are packed up closely into masses and wedged together in iron frames, so that they form, as it were, solid blocks; the types or wood-blocks when required to be printed from are placed in the press, and rolled over by a roller smeared with printing- ink — this roUer is coated with an elastic substance made of glue and treacle, and resembling india-rubber. It is worked to and fro on the " inking-table " (a smooth iron PKISTING-PEESS. slab fitted •w'itli a receptacle for ink), in order that the ink may be evenly distributed over ita surface — a point to which great care and attention, and no little skill, on the part of the workman, is directed. The ink, being rolled over the type, covers and adheres to the surface of the projecting parts. The paper is placed on a frame turning upon a hinge, and is secured in its place by anotlier frame brought down upon it. These frames, with the paper, are now turned down upon the blackened surfoce of the t\'pe, and the whole — paper and t\*pe — passed under the printing press, where, by the working of a Ivaudle, a K 2 132 ABTS iJSD TEADE PBOCESSES. piece of iron is caused to descend and press evenly and witli great force upon them. On being withdrawn, and the ixames opened, the paper is found to have received a perfect IXKIXG-TABLE. impression, in. ink, of the t}-pe upon which it was impressed. This process, of course, can be repeated to any extent, and as many impressions produced as may be required. In plate-printing, the plate is first warmed, and all the engraved parts are filled in with ink, the superfluous iuk being wiped, off. and the siuiace cleaned bright by using a little whiting (which is rubbed on the hands), lea^"ing only the indented parts full of ink. The paper (in a damp state) is then laid on the plate, with a fold or two of flannel over it, and the whole is carried, by timiing the handles of the press, between two rollers, which compress the plate and paper together so forcibly that, when removed, the ink is foimd to have left the plate and attached itself to the paper, forming an impression. Printing is now in xery many cases done by machinery, worked by steam power, so that a very large number of impressions can be produced in a very short time, as in AKTS A^D TRADE PB0CES6ES. 133 the case of newspapers, the whole impression of which (amounting to many thousands) is printed in a few hours. Printing in colors of various tints, so arranged as to form a picture, has lately been much resorted to. The usual method pursued is to print one color, and when that is dry, to print the next, and so on till the picture is complete ; but a machine has been invented by which many colors may be printed at one time. CAJLB&A FOB STESS08C0FIC PICTTBES. PnOTOGBAPHT. The principle of this art depends upon the property which certain chemical preparations (chiefly those of silver) possess of being blackened by exposvu-e to Hght while in contact with organic matter, and that in so gradual a manner that event- degree of shade may be represented. Xow, as the various appearances of ever\-thing we see depend upon the eflects of 134 AETS A>'D TRADE PROCESSES. light and shadow (together with the peculiar color of the objects themselves), it follows that if these lights and shadows can be transcribed, we shall have a representation of the objects, minus their own proper colors — and this is what photogi'aphy eftects. For the purpose of bringing the objects to be taken within a small compass, and for increasing their vividness, an instrument is used called a camera, in TIG. 3. which there is an achromatic arrangement of lenses (9ho^vn in figs. 2 and 3), which produces a picture on the paper or glass to be affected by the Light, in the same way that a common magnifying glass will, if held at a proper distance from a piece of paper, but much more perfectly (fig. 1). The effect of this camera-picture on the paper or glass when ARTS AND TRADE PROCESSES. 135 properly prepared and subjected to its influence, is to darken the paper in all those parts which in the camera^picture are the brightest, and to leave imaftected those parts which are the darkest, thus producing what is called a " negative picture," having the lights represented by sliadows and the shadows by lights. This is used to form the true or " positive " pictiu-e, which is done by placing the negative on a piece of prepared paper, and exposing it to the light. The negative having been made partly transparent by wax (as will be further explained), and the parts of the pictiu-e which are to be dark being left transparent, the light passes through them and blackens those parts of the prepared paper behind, while those which are to be light, being dark in the negative, exclude the light and thus pre- serve the paper at the back from being darkened ; the paper is thus ati'ected in the contrary way to the negative, and is therefore a true picture of the lights and shadows of the object copied. This is the principle of all photographic pictiires, but with numberless variations in its practice ; it would therefore be impossible here to describe the particulars of each process, beyond the most simple. Perhaps of all the various arts discovered by man, this is the most beautiful, producing a perfect likeness of any being or object in a few moments, and with a truth not to be equalled by years of study and practice in other ways. One of the earliest discovered and simplest modes of forming a sun picture consists in using the object itself (where this is possible) to fonn the negative. This can only be done when the object is flat, as a manuscript, a picture, a leaf, or a piece of lace-work ; a piece of paper washed over with a solution of common salt, dried, and again washed over ^\-ith a solution of nitrate of silver, will answer for this purpose ; it shoidd be prepared by candle-light, as daylight blackens it, and it should be kept i'lxnn the light till the moment for use. If this paper, having the object to be copied placed on it and kept flat by a piece of glass pressed firmly on by a contrivance shown in flg. i, be exposed to the sunshine, it will be blackened in all places but those kept from the light by the darker parts of the object, and the lights and shadows 136 ARTS ASD TRADE PROCESSES. \^-ill vary accordiugiy as the various parts of the object itself are more or less transparent. When the eftect has been produced to a sufficient degree, the paper should be removed and at once washed in a solution of hyposulphite of soda, which removes all the superfluous silver (which otherwise would be darkened by the light) ; when removed from the hyposulphite of soda it should be well soaked in clean water. This when finished is a true negative picture of the object, and can be used to produce the positive. The negative should first be made partly transparent by brushing it over with some melted white wax, then placing it between folds of blotting paper and passing a hot iron over it, the blotting paper will absorb all the superfluous wax, and the negative will be fit for use. A piece of paper prepared like the first with salt and nitrate of silver, should be placed against the front of the negative, kept smooth by a piece of glass, and exposed to the sunshine for a quarter of an hour or more, taking care that the back of the negative is exposed to the Hght and the prepared paper behind; a positive picture will be produced, which is to be at once treated with a solution of hyposulphite of soda and washed with clean water, as was the negative. Any number of positive impressions may thus be produced. The " Calotype " or " Talbot^-pe " process may be per- formed as follows, recollecting that all these processes must be conducted by candlelight, or in a room having the window covered with yellow silk, or some other substance excluding white light. Select a piece of paper of an even surface and ARTS A>'D TRADE PROCESSES. 137 structure, such as AVhatman's paper, brush it over with a solution of nitrate of silver — about sixteen grains to an ounce of water — and let it dry, then fold up the edge of the paper all round and dip the surface to which the solution of nitrate of silver has been applied into a solution of iodide of potassium — an ounce to a pint of water — contained in a shallow vessel, and let it partly dry ; float it for a quarter of an hour in a vessel of clean water, moving it gently about so as to remove all soluble matter, and hang it up by a comer to dry, taking care to let nothing touch the surface. A^^len about to be used, this pa])er must be brushed over (using a soft camel-hair brush) with a mixtiu'e, in equal quantities, of a solution of nitrate of silver — fifty grains to an ounce of water — -and a saturated solution of gallic acid, forming what is called the " gallo-nitrate " of silver. Leave this solution on the surface for ten minutes, and again immerse the paper in two or three successive portions of pure water, moving it to and fro ; this, when nearly dry, is in a fit state to place in the camera, and is an exceedingly sensitive paper, which in a good light will be aftected in a few seconds. AVhen the image has been impressed by the camera, the paper should again be brushed over ^^^th the gallo-nitrate of silver, and held either near a fire or a plate of hot iron, so as to receive a gentle warmth ; the impression will now come out, of a deep rich colour. Dip it into warm water for a few minutes, and put it into the h\i)osulphite of soda bath — an oimce to a quart of water — fi'om which it is finally removed and placed in a large vessel of piu-e water for several hours. When dry, it is complete, forming a good negative, which, when waxed, may be used to print positives as before described. The "Collodion" process is conducted as follows. HaWng selected a plate of glass of the required size and of good quality (patent plate answers well), clean it thoroughly with rottenstone and spirits of wine, and polish it Avith a clean dry linen cloth ; then hold it on the tips of the fingers and thumb in a horizontal ])osition, pour upon it a small quantity of the " iodized collodion," and so incline it from side to side, that all the surface shall be covered A\-ith the collodion, that which is superfluous being returned to the bottle 138 AETS A>'D TRADE PEOCESSES. by pouring it from one comer of the glass. In a few minutes the coating of collodion vriU be dry, and should form a perfectly even surface, A^-ithout air spots or uneven markings. The iodized coUodjon is made by dissolving gun- cotton in ether, and adding spirit of wine and iodide of ammonia. The glass plate coated Avith collodion is now dipped into a solution of nitrate of silver — thirty grains to an ounce of water — and allowed to remain two or three minutes ; when aU the superfluous fluid has drained off, the plate is ready for use, and is exti-emely sensitive to light. When the impression has been produced by the camera, a solution of p^To-gaUic acid, mixed Adth a little acetic acid, is poin-ed over the surface, Avhich brings up the image ; when this is developed to a proper extent, the surface must be washed Avith clean water and aitenvards \\-ith a solution of h}-posulphite of soda, which dissolves out all the silver from those parts not darkened by the light in the camera, leaving the glass in those parts quite transparent. A negative is thus obtained fit to print from in the usual way, but glass being more transparent than the waxed paper, it produces a more perfect positive. The siu-face thus pre- pared should be coated with a varnish, made by dissolving amber in chloroform, which is done by pouring it on and decanting the superfluous varnish similarly to the mode of coating with collodion ; this varnish di'ies in a few minutes, and preserves the surface from injury. Sometimes these negatives are converted into positives, instead of being used to print from ; in these cases the surface is coated Avith black japan, and the collodion, having a whitish surface, OAving to reduced silver, shows up in comparison -with the black varnish which is seen through the transparent parts. These positives are extremely sharp and well defined. The " Daguerreot}-pe " process consists in forming the image on the surface of a metaUic plate (copper coated Avith silver), which is first polished to a perfect surface like a looking-glass, then exposed to the vapoiu* of iodine in a properly-constructed box, afterwards to the vapour of chloride of bromine, and again to the vapour of iodine ; this produces a thin film of a mixture of bromide and iodide of ARTS AND TRADE PROCESSES. 139 silver, which covers the surface of the plate, and is very- sensitive to light, which reduces the iodide and bromide to the metallic state in a few seconds. The plate is then exposed to the action of the light in the camera, and when sufficiently aftected, exposed to the vapoiu" of niercurv-, the mercur}^ being put into a box, and heated by a spirit lamp ; the mercurial vapour adheres to all the parts of the silver reduced by the light, and forms a light-coloiu-ed amalgam, con-esponding to the lights of the objects represented. The plate is then washed with a solution of h^-posidphite of soda, which removes all the bromide and iodide of silver not reduced by the light, and exposes the highly-polished siu^ace of the silver, which forms the shadows of the picture ; this is now " fixed " -svith a verj' weak solution of chloride of gold and h^-posulphite of soda, which is poured over the surface and heated while there by applying the flame of the spirit lamp to the back of the plate for a minute or two ; the solution is then poured off, and the pictiu-e when washed with water is complete. Many photographic pictures, whether Talbotj-pe or Da- guerreotype, are taken double for the " stereoscope " (tig. 5). This is an instrument haying two lenses (one for each eye), through which the tv\o views may be seen. The principle is this: — Every object is seen by each eye in a slightly 140 AETS A>'D TBADE PEOCESSES. different vieTv; for instance, if you look at the edge of a print — placing the printed part towards your right hand, and bringing the edge in front of the fece between the two eyes — by closing the right eye, the left will see the back of the print only, but by closing the lett eye the front of the print may be seen, and the front only. The stereoscope presents both of these views to the eyes at once, as when we look with both eyes, and the objects have therefore the appearance of projecting, as do read objects. To take these ^iews, the slide after one view is taken is moved about four inches on one side, and then the other is taken : the distance moved corresponds to the distance between the eyes, and therefore produces the correct -s-iew for each. The box for the stereoscopic slide is shown at fig. 6. in which a is the first A-iew to be taken, while the other half of the glass is kept dark, at b, and c is the shutter for a. booe:-bi>'di>'g. The sheets ox which a book is to be made, when properly folded (into half for foHo, quarter for quarto, &c.) are pressed flat in a press and then placed, one or more at a time, on a board behind a frame called a " sewing-press " (fig. 1), which has pieces of string or cord (called bands) tied in an upright ARTS AXD TRABE PROCESSES. 141 position, and against these the folded edge of the sheet is brought in such a manner that the bands may be sewn on to the back of the sheet by a thread being passed from the inner part of the folded sheet to one side of the string, then in again on the other, and so on for each cord till they are fastened on to the first sheet, when another is placed on the top of the first and sewed in the same way. When all are sewn, the back is glued thickly over, and the book is fixed between tvvo boards in a press and the back beaten till it is ciured; the sides and front are then cut smooth with an instrument called a plough (fig. 2), which works in the grooves of a FIO. 2. press where the book is fixed, and a knife (which forms part of the plough) being passed backwards and forwards, cuts through the edges of the book and makes them smooth. 142 ARTS A>'^D TEADE PEOCESSES. The covers — made of a thick pasteboard called "mill- board," and cut to the right size by shears (fig. 3) — are fitted to the sides of the book, the ends of the string-bauds are FIG. 3. then passed through holes in the sides of the boards, and are beaten flat and glued down. The book is then covered with cloth, vellum, paper, or leather, as desired, and finally pressed in a powerful press to make the leaves smooth. Ornaments, such as gilt bands or corner decorations, are produced by gold-leaf put on and stamped by means of tools engraved at their ends, or, where the margin is to have a pattern or line on it, by means of wheels with engraved edges (fig. 4). Leather-backed books are glazed on the outside Avith white of eggs, which forms a kind of varnish when dry. Books have lately been bound ^^^^ ^ . without any sewing, by "Han- cock's Patent" process. This consists in having all the sheets folded into double leaves, and the folded parts all brought evenly to a ciured form for the back of the book by means of a mould or hollow cut in the edges of two upright boards (fig. 5) ; they are ARTS AITD TRADE PROCESSES. 143 then removed to a press which holds the book tightly together, leaving this cnrved back just projecting in front of the press-boards. The back is smeared ^_, ^vith india-rubber dissolved in naptha, which r''\Jj^p^ I when dry is several times repeated, till a I ^ I coating of sufficient thickness is produced, I, when it is covered ^^'ith cloth or linen and the book is ready to be finished in the usual way ; thus the sewing is quite dispensed with, for the folded edge of each sheet is held to the next one by a thin coating of india- FIG. 6. rubber. This plan allows great freedom in opening, and for thick books produces a level surface much superior to those bovmd in the old way (figs. 6 and 7). PAPEE-STAINING. This name is given to the process for making paper- hangings for the decoration of the walls of apartments. The colors used in this process are all what are called body- colors, or those which are not transparent, but mixed mth whiting or prepared chalk and a small quantity of size to the required tint. The colors are applied by means of Avooden blocks hanng their surfaces so engraved that the pattern shall project ; all the pattern is not engraved on one block, but only that part of it which is to be of one color, and the number of blocks required depends upon the number of colors in the pattern — usually three or four. The paper is printed in pieces of about twelve yards in length ; these are first " grounded," that is, colored all over with the color intended to form the ground of the pattern, and hung on poles to dry. The blocks are applied to a sort of sieve, with a leather bottom, "GiiOUSDlSG" IlLE PAPEIi, on wliicli some color is spread with a brusli. and wlien the block is taken up sufficient of the color adheres to give a PKIM1>G THE PA.I11;K>. good impression on the paper. Each block has a register, AKTS AXD TRADE mOCESSES. 1 io ■which protlucea a little mark at the edge of the paper, and serves as a guide in applying the succeeding blocks, so that when printed they tit into and correspond with each other. " Flock " paper is produced by printing part of the pattern in a varnish of boiled oil and whiting, and laying the paper so printed in a trough or tray over whicli the flock is sprinkled. The flock is made by grinding shreds of cloth of the required color in a mill. This rough surface gives a very rich and velvety appearance to the paper. FLAX MAXUFACXrnE. Flax, before being spun into "yarn" for wea\-ing linens, undergoes several processes, to separate its fibres sufficiently, and to rid them of all short and uneven portions. The first operation consists in a kind of fermentation called "retting," the stalks of the flax being packed up in bimdles and steeped in water, or exposed to damp air, spread out, till tliey soften and become fit for the next process, called " breaking." This is done by contrivances which beat and bruise or give it several shaq) bends, the object being to break off the outer part, called the " boon," and leave the inner fibres or " harl " free ; this, which is the part to be used, is thus in a great measure freed from the outer part, but to do so completely it is scraped with a blunt kind of knife till all the "boon" is gone. The next process is called "heckling," a sort of combing, in which the flax is dragged through brushes of fine iron spikes, used closer and closer till the flax is combed out quite fine and perfectly free from knots or uneven pieces, being beaten from time to time to break or separate the fibres. During tliis process much of the short and uneven fibres collect in the " heckle," and is called "tow," whicli has to be separated and the fibres arranged similarly to "cardinij" cotton (see "Cotton Manufacture"). The flax* has now to be drawn out, doubled, and drawn out again into "slivers," also in the same way tliat is described for drawing out cotton, and these slivers are finally twisted into yarn, being previously wetted t(j take oif their stiflness. The yam is then wound upon bobbins, forming the material from which linens, muslins, and other goods are woven. L CAIilOOS, OS IiESIGM>(i EOOil. GLASS-PAI>'TI>'G. Of glass-painting there are tsvo kinds, the one being known as "painted," and the other as "stained glass." In the former the design and coloring are produced by the applica- tion, to the surface of colorless glass, of transparent pigments of various colors, ■«"hich, under the action of the furnace, become vitrified and incorporated vrith the body of the glass. In this manner of glass-painting — ^which is capable of none of the poweritul and rich effects of color peculiar to stained glass — it will be understood that the process much resembles the practice of the picture painter. In tne one case canvasses are used, and in the other sheets of colorless glass ; the picture-painter using colors mixed with oils and varnishes, the glass-painter colors made of earths and metals, and mixed with a flux, which, under the action of fire, vitrifies his work. It is qmte possible to produce a large com- ARTS AXD TRADE PROCESSES. 147 position, containing many fissures and a great variety of colors, on but few pieces of glass. Indeed, one of the necessities of making a window of " painted glass " in several pieces, is simply to avoid the danger of breakage, in \ising sheets of too large a size. The various pieces are joined together with lead work of precisely similar nature to that which is used in the diamond " quany-glass " seen in the windows of covmtry cottages. '• Stained glass " differs from glass-painting in very many particulars. In this case the colors, instead of being laid on with a brush as in painted glass, are formed in the substance of the glass itself. This necessitates the use of separate pieces of glass for every color or tint required, and thus the process in some degree resembles that of mosaic work, a term, indeed, which is often applied to this kind of glass- painting. The first process in producing a stained glass CUTTING EOOAI. window is tlie making of the design, colored or otherwise. This oiB.ce is, of course, that of the artist, who is at the head GLAZING THE WoKK UP. of his establishment. From liis design, which is always made to a small scale, the full-sized drawings or cartoons are made, auts .o'd trade peocesses. 149 by the artist and his assistants. "When finished, with all details and colors determined, they are placed in the hands of the glazier, who cuts Avith his diamond the glass of the required shapes and colors, respectively, so that when his task is complete, the window, as laid out on the "cutting-hoard." much resembles a child's puzzle — each piece of glass, although often of the most com- plicated form and minute size, fitting \vith accuracy to the other pieces by which it is surrounded. This process com- pleted, the next course is for the painter to produce on the blank piece of colored glass prepared for him by the glazier the various outlines and shacbngs, as represented in the cartoon, it being his business to lake such means as will ensure the production of a faithful copy. This outlining and shading is produced by the use of a bro%niish or warm grey tint, which is generally used a little over all the colors represented in the work. There are some slight gradations of these broAvn tints used occasionally, principally when it is desired to paint the flesh shadows \\"ith some separate tint, but generally it may be understood that the office of the painter in stained glass is not to produce the colors, but by his brown shadow- ing to bring out the design and forms of the composition. AVhen the glass, thus shaded and outlined, has passed through the furnace — where the shadows are fll-nall-. ^•itrified — and been allowed gradually to cool, the glazier fits it together with lead-work, soldering in all the pieces, then the whole is made weather-tight, and the stained glass window is complete. MULE FKAMES. COTTON MANTXrACTURE. After the cotton is sorted, and the grosser impurities picked from it by hand, it is dressed by the " combing machine," or subjected to a machine (called a "mllow," ht;*D TRADE PROCESSES. beaten as it passes, to get rid of dust, and a draught of air produced by a l)lo's\-ing apparatus assists in the same object ; CAIir>I>G MACUI>"E. it is thus entirely freed from all impurities. The cotton is then carried to the " carding machine." for the purpose of having its fibres all laid parallel with each other ; this IiEAM-ING MACUINE. machine is, in fact, a sort of comb, and consists of cylinders having fine wires projecting from their surfaces acting in AKTS A>'D THADE PROCESSES. 153 diflferent directions, so as to draw out the fibres till they all lie in one direction, forming a kind of " fillet," called a " card," which is carried by rollers into a tin can and then subjected to a process called '" drawing and doubling." As the " card ends " are not yet sufficiently parallel in their fibres, they have to be passed between three sets of rollers, the luulerniost of which are fiuted on their surfaces, the upper ones being covered with flannel. These rollers act in a ])eculiar manner ; the first pair pass the cotton at a certain rate on to the second pair, which woidd pass it on to the third unchanged if they revolved at the same rate as the first pair, but they are tiu'ued a little faster, and therefore stretch the fillet of cotton at an even and regidar rate, and in such a manner that it is not broken ; the tliird pair, going faster than the second, again stretch the fillet. After the fillet has passed through it is doubled, passed through again and again, till it is quite uniform in its structure, and drawn out by these stretchings very fine, it is then called a " sliver." When it is draA\Ti as fine as the kind of cotton admits, the BOBBIN FRAME. first twist is given to it by the "roving" machine, which twists it into a soft card, delivers it woimd on " bobbins," and it is finally twisted into yam by the "winding machine." These processes are carried on with great precision and rapidity, and, by the aid of these machines, one man is able 154 ARTS AND TEADE PROCESSES. in a day to produce as mueli yarn as the most expert spinner by hand coidd furnish in a year ! Cotton, vuitil about 1760, was all spun by hand. A little later, James Hargi'eaves invented the " spinning-jenny," and ArkwTight aiterwards WISDI>G lli.Clil-NL improved the " carding machine ; " the " mule-jenny " (see Heading), invented by Crompton, was a still further improvement. The cotton, when spun, is called yarn, which is used for wea%'ing into calicoes and other cotton goods. Cotton thread is made by t^^•isting (by machinery) two or more yarns into one, which are afterwards di'essed vriih starch, and wound on reels or into balls. WOOLLEX MA^'^FACT^RE. Wool is almost exclusively derived from the fleece of the sheep, goats' wool being only occasionally used. Wool difiers from hair in possessing a notched surface, giving it the verj^ useful qviality of " felting," and enabling the fibres to adhere into a mass when pressed and beaten together, the notches catching into each other. Woollen articles are chiefly of two kinds, " woollens," or those partly felted and made from "short" or "clothing" wools, called "cloths," and those made without felting Irom "combing" AUTS AND TEADE PROCESSES. 155 or " long " wools, as " merinos," " stuflfs," 'D TEADE PEOCESSES. heddle, aud so ou. These lieddles can be raised alternately by a pidley attached to treadles -worked by the weaver's feet, and it follows, that when one of the heddles is raised, every alternate thread of the wai'p is raised also, a space of a ti'iangidar form being left (fig. 2). Throngh this space the weaver throws the "shuttle" (fig. 3), which is a piece of wood pointed at each end, bearing a reel of "weft" in its centre, which weft-thread nn^vind3 as it is thrown through. The other heddle is then raised, and the shuttle thrown back again, each time lea^-ing a line of weft behind it. In this way the crossings of all plain fabrics are produced, a con- trivance being used betv\"een each throw to press the weft close to the former one. If instead of one half of the warp-threads being up and the other half down at FIG. 3. the time the shuttle is thrown, one only is raised at every fifth thread, the intervening four being down, and the one that is raised difiering at each throw of the shuttle, a kind of struc- ture is produced called "tweeled" or "twilled," such as satin. o o o\^o o o o oxbi/o G bombazine, &c. ; fig. 4 shows the appearance of the edge of such a structure. If the warp consists of alternate threads of difierent colors, white and blue for example, it is clear that either color will predominate where the warp thread of that ARTS AXD TRADE PROCESSES. ]59 particular color is most seen. In fig. 5, a a a a represent white, and h b b b blue tkreads, and this will show how the pattern on any structure, although the same on both sides, is blue on the one side where it is wliite on the other, as in damasks, or raised on one side where it is s unk on the other, as in dimity, or diaper. Bi.£ACIU.V(i WOKILS. BLEACni:S^O. The chief object of bleaching is to get rid of the natural coloring matter which always tinges cotton, silk, &c., as pro- IGO ARTS AXD TBADE PEOCESSES. duced from the raw material, and also to get rid of any greasr matters, or stains from accidental causes. Cotton is not only reqnired to be bleached when intended to remain white, but also before dyeins; or printing, the colors being thereby rendered more uniform and brilliant. The oldest method of bleaching consisted in simply exposing the goods, moistened with water, to the action of light and air, by spreading them out on the grass, and hence the term " grass-bleached ; " but this is by far too tedious a process for the present day, when the manulacture is so great and the consumprion so rapid. The process of bleaching cotton goods consists in boiling them first in water, then in a mixture of lime and water, and then in a solurion of soda, soaking them in a solution of chloride of lime, afterwards in water acidulated with SIXGEI>'G APPAILilUS. sidphuric acid, and finally in pure water. Linens are chiefly bleached by repeated boilings in solutions of potash or pearlash, and afterwards in chloride of lime ; wool by soakins: in warm water, exposing it to the vapour of sulphur, and finally washing in a solution of soft soap. AKTS AXD TRADE PROCESSES. 161 Before beinrj printed, it is necessary that all the loose fibi'es should be removed from the surtace of the goods. This is eftected by " singeing," which is done by causing the goods to pass over a red-hot roller, setting fii-e to the tine fibres projecting from the surface only, but Tsnth a motion too rapid to allow the fabric to be scorched. This process, and also the apparatus by which the articles are IJKYISG APPAlLiirS. dried after bleaching, are shown in the accompanying illustrations. The latter consists of a senes of hollow rollers heated bv steam, over which the goods to be di'ied are passed, a current of air being admitted to carry off the vapour. CALICO-PRIXTiyG. Calico-printing is executed either by hand (with wooden blocks having the pattern engraved — projecting — on their surfaces) or by means of machinery. Printing by hand- blocks is a tedious operation, and is now almost superseded bv the cylinder. The hand process is verv* similar to that made use of in paper-staining (which see) . Cylinder-printing M CALICO-PEINTING WOEKS. is a mucli more rapid process, conducted by means of a brass cylinder with tlie pattern engraved on its surface, which is made to revolve against another cylinder covered with ilannel, and charged with color from a trough into which its lower part is dipped. The calico is passed over a large cylinder made to revolve in contact with that on which the pattern is engraved, and which is charged with color from the one below it. Fig. 1 shows this arrange- ment, a being the large cylinder with the calico round it, b the engraved cylinder, c the color cylinder, and d the color trough. As the engraved cylinder re- volves, it prints the pattern at each revolution, and tliis is repeated again and again, to the whole length of the pie.ce of calico. In some machines there FIG. 1. ABTS AND TRADE PROCESSES. 168 are several enu^*aved cylinders, each priiitinp; its own color, and so arranf];e(l that the colors shall fit into the parts of the design requiring them, the whole making up tlie complete pattern. Before being printed, the calico is prepared by being AGEIXG PKOCESS. passed through a preparation, called a mordant. caj)able of fixing the colors, and preventing them being washed out, and M 2 101 ARTS AXD TRADE PROCESSES. several of these are used, according to the colors required. The colors are thickened with paste, so as to prevent thena from running into each other when printed. Muslins, chintzes, &c., are printed in a similar manner to calicoes. A\Tien the pieces of calico come from the printing cylinders, they are made to pass upwards through holes i)i;vi>G Kouii. in the ceiling to a room above, where they pass over surfaces of iron heated by steam, so as to thoroughly dry them ; they then descend through the floor into the printing room, where they are packed. The process called •• ageing " consists in exposing the calicoes to the air for a certain time, to take off the harshness and stiffness peculiar to new goods. In some cases the colors themselves are not printed on tlie goods, the mordants being used instead, and the whole piece is then boiled in a vat of dye-stuft', which, however, only adheres to the parts printed with the mordant, all tlie rest being easily got rid of by simple washing. DYEIXG. The art of dreino: does not simply consist in coloring the difterent substances ; if this were the case, the color would be washed out as easily as imparted. Xearly all the colors used in dyeing being of vegetable origin, it is necessary to apply some substam-es to the fabrics to be dyed which shall fix the colors in the grain. Of these (called '' mordants "') the chief are acetate of alumina, acetate of iron, and i-hloride of tin (substances well known to chemists), whic-h have the property of making the coloring matter insoluble, so that it cannot be washed out. There are various ways of dyeing. If the fabric has to be dyed all one color, it is dipped in the mordant, dried, and 166 AETS A>'D TEADE PEOCESSES. aftei'wards boiled in a solution of the dye-stulF. If a colored groimd with white figures is required, then the figures are printed on it with what is called a " resist," that is, some substance thickened with gum, paste, or pipe-clay, which will resist the action of the mordant and dye-stutf, so that when the fabric is afterwards rinsed these figures remain white. If the ground is to be white and the pattern dyed on it, then this is printed with the mordant and the color adheres only to the parts printed, although the whole be boiled with the dye-stutf, what little may adhere to the ground being easily washed out in the rinsing. Sometimes the kind of mordant used determines the color of the dye ; for instance, madder will dye red with the chloride of tin. and black with the acetate of iron. If we now suppose a piece of cloth to be printed in lines of acetate of iron, and figures of chloride of tin, when the whole is boiled in the madder vat, the cloth comes out with black lines and red figures on a white ground. Another point to be considered is the kind of stufi" to be dyed, whether cotton, silk, or woollen, or a mixture of either, for what will take one kind of dye wiU not always take another, and advantage is taken of this to dye two colors at once, or part white and part colored. A table-cover, for instance, woven vrith worsted and cotton, can be boiled in various kinds of dye, and produce white and blue, or white and red, for that dye is selected which will attach itsell" only to one kind of fabric, and leave the other. ARTS AXD TEADE PKOCESSES. 167 INIany other cbemical qualities of the substances used as dyes, and of the substances to be dyed, are also taken into consideration. One of the chief of these is shown in dyeing with indigo. This substance (a vegetable extract) as brought to England is quite insoluble in water and unfit for use as a dye ; but it is made soluble, and at the same time almost colorless, by mixing with lime, sulphate of iron, and water. These substances deprive it of its oxygen, and the straw-colored solution is then used for dyeing, the substances boiled in it attaining — as the indigo regains its oxygen on exposure to the air — a deep blue color. With dyeing is often associated the art of " scouring," for a knowledge of the properties of the dye-stufls used enables the Avorkman to discriminate bet-ween what will brighten and what would injure the goods to be cleaned. CALEXDERIXG. The process of calendering is resorted to for producing a fine smooth surface on calicoes and other goods, and for rendering them sufficiently even to be printed upon (see " Calico-printing "). The calendering machine consists of a set of five rollers, constructed to revolve at unequal rates, so that the one which turns upon the face of the calico not only rolls it between itself and its fellow, but — turning faster — j'uh- it and gives a gloss to the surface similar to the effect which would be produced if the goods were laid on a table, and the roller rubbed over them instead of being rolled. These rollers are very curiously con- structed. They are made by packing many hundreds of round pieces of pasteboard — having each a square hole iu the centre, and several smaller circular ones in the margin — on to a central bar of iron, with similar bars through the smaller holes, until a sufficient number have been added to produce the length of roller required. !N'uts are then fitted to the ends of the smaller iron bars, and these being screwed tightly, compress the whole into so solid a mass, that it can be turned in a lathe to a perfectly smooth surface, which is (unlike wood) not liable to crack, and, being slightly elastic, does not crush the goods, as metal rollers would. 168 ARTS AST) TRADE PROCESSES. BEEAB MAKING. This process is miicli the same whatever kind of meal or flour may be used, whether wheaten, barley, &c. A certain portion of the flour is mixed with warm water (in which a little salt is generally dissolved), some yeast or "barm" (the froth from the fermentation of beer) is added, and the whole worked together to a pasty consistence, this is put into a pan to keep warm, and is called "the sponge ;" besides flour and water nearly every baker mixes his sponge with a certain proportion of potatoes boiled to a '* sc|uash." and passed through a sieve to separate the rinds. In an hour or so it swells up to double its original size, from the fermentation which is going on producing a kind of gas called " carbonic acid," whieli being Ibrmed in every part of the " sponge," inflates it to a great extent. After a time it sinks down (most of the gas escaping), and begins to rise again ; it is then mixed Avith the remainder of the flour (and some water if necessary), and the whole thoroughly kneaded togetlier with the hands till it is all of an equal consistence — this should be neither too stiff", nor so soft as to stick to the hands. It is now to be cut up and weighed out into pieces to form each loaf. The oven in which the bread is baked is made of " fire-brick," and so embedded in earth or brickwork that Avhen heated it shall not readily cool ; this is heated with coal or wood till it is nearly red- hot and the loaves are put in and left till baked. SUGAR REFIN'ING. When brown or raw sugar is refined it forms the white crystalline product known as loaf sugar. The process involves many ingenious arrangements in its detail, but the essential object to be obtained is the separation of all coloring matter from the raw material without producing any more by the process, which is a greater dilHculty than would at first appear, for all solutions of sugar eAaporated in the open air become to a great extent colored, and the longer the exposure, and the higher the temperature, the VAC UU Jl-PA.N. worse the product ; a substance forming called " caramel," which discolors it. The brown su'j;ar is first mixed with a very small quantity of boiling water, just sufficient to form a thick pasty mass, which is put into conical pots (figs. 1 and 2), and allowed to drain, the small quantity of water washes out only the brown part, and leaves the crystals pretty white ; they are tlien dissolved in Avater, mixed with some bone-black and bullock's blood ; the bone-black is the charcoal from burnt bones, and has the power of taking away the color of most vegetable solutions, the bullock's blood is iised as afibrding a cheap kind of albumen, which when the solution of sugar is boiled coagulates and entangles all the floating matters so that they may be removed by filtration. The liquid is boiled for a time, and then put into a cistern excluded from the light, having holes at the bottom into which long tubes of thick twilled cotton are fastened, through which the solution runs as bright as water ; they all hang down into another cistern below, also kept from the light, 170 ARTS JLN'D TEADE PBOCESSES. from w-hich it is pumped up into the evaporating apparatus — a copper vessel entirely air-tight, heated by steam and having a powerful air-pump attached to it by which all the vapour and air are removed as the s}Tup becomes hot; this is called a "vacuum pan" (see engraving), and by this the syrup is con- densed to the proper consistence, and is put into moulds of the shape the loaf is to be, having holes at the lower part which are plugged up, the syrup as it cools forming a solid mass of crvstals; these moulds are arranged in rows over a channel leading to a proper receptacle, the plugs are taken out from the holes at the bottom of each and some pure concentrated syrup is poured on to the upper part ; this slowly descending filters through the sugar, TIG. 1. carrying with it any " caramel " that may have formed, finally escapes at the hole, and runs into the cistern ; this completely whitens the sugar, and gives it a brighter and coarser grain. The loaves 'Q^^ > are then taken from the moulds, dried in an oven at a gentle heat, and finally packed in paper for sale. If the pointed ends are discolored or ragged the loaf is put into a lathe (fig. 3) and the end turned to a proper figure or cut oft\ BREAVIXO. Beer is made by pouring boiling water upon ground malt, and after a time drawing it off, which is repeated until all its soluble parts are removed and dissolved in the water ; tlie liquor resulting is called "' sweet wort," which is then boiled with a certain proportion of hops (the dried "stobules" cir dowers of the hop plant), and the liquor allowed to cool. It is then mixed with a small quantity of " yest," which is the scum throA\'n off by a former brewing, and the whole is allowed to ferment till nearly all the sweet sugary matter which was got from the malt is converted into spirit, it is then put into casks and allowed to ferment slowly, in which process it throws off more yest, which is collected, as seen in the cut, for the next brewing. It is then bunged up in the barrels and kept for a time, when it is fit for use. in large FEKilESTING KOOil. breweries machinerv of various kinds is employed, such as ENGINE KOOil. punips for pumping iip water, taps for drawing it off AlAbU ri's. imchinory for stirrinc: up the inasli in the " masli tun." :uul also the hops in tlie boiler, to prevent them ImrninjT at the bottom of it. The '• cooling tloor" is a contrivam-e "174 ARTS XSD TEADE PROCESSES. for coolins: tlie wort, consisting of a series of pipes which pass in a serpentine manner through it, and through whicii cold water is made to flow. The kind of beer, whether ale or porter, chiefly depends upon the kind of milt used ; for COOLING FLOOE. ale. verv pale malt, called " amber," while for porter, burnt malt is employed, and hence the color of these two descriptions of beer. If the fermentation is not carried far enough the beer will be too sweet, and if too far it will be sour. DISTILLATION. The process of distilling consists in converting the fluid to be distilled into vapour, and condensing it into a fluid in another vessel. By this process the more volatile parts of any fluid are separated from the rest ; for example, if brandy be distilled, the spirit or alcohol it contains will be converted into vapour and will condense in the receiver comparatively pui-e (see '■ Alcohol "). leaving behind in the still the water, colorins: matter. &c., so that the spirit is colorless, although the brandy may have been quite brown. Also, if common water be distilled, pure water will pass over, and the earthy matters wliicli the water had contained will be left behind (for all ordinary water contains considerable quantities of earthy matters, dissolved out from the earth over which it flows) . The vessels used for distilling are very various in their forms, to suit the different fluids, both as to quantitv and quality (see " Still "). There is a contrivance latelv used for distilling spirit from the fermented wash con- taining it, by which it is allowed to flow into an apartment full of double floors, a few inches above each other, the upper ones being made of thin copper perforated all over with minute holes, and on which the wash is allowed to flow to the depth of about an inch. Into the space between the upper and lower parts of each floor steam is admitted, which, rising through the little holes, is condensed by the wash, giving out its heat to the spirit contained therein, and causing it to be converted into vapour, which passes oft' from the spaces between the floors to a condensing apparatus with which they all communicate. 176 ARTS AXD TKADE PROCESSES. CrILDIXa. Gilding consists in covering the surfaces of various articles veitli a thin layer of gold, and may be divided into two kinds, quite different processes and practised by difterent artisans. The first is " oil-gilding," which is a mechanical application of gold-leaf to some adhesive surface, the second is " water- gilding," and is a chemical process. In oil-gilding, where frames, &c., are to be covered with gold-leaf, the first thing necessary is to obtain a smooth even surface on which it will lie, but as carved frames are expensive, ornaments of a kind of putty are fixed to the frame, and coated with whiting and size. The gold-leaf is made to adhere easily to this clammy surface, by simply damping it, and pressing the gold on by means of a piece of cotton wool, afterwards gently brushing it into all the markings. Wood and other articles to be gilt are coated A\'ith " gold-size," — a sort of varnish — and when this is nearly dried, so as to be what is called " tackey," it will hold the gold in the same way. AVhen lettering is to be done in gold, the painted or varnished siu'face is first brushed over with whiting, which prevents the gold adhering where it is not wanted, the writing is then execiited in gold-size, and the gold-leaf applied by pressing the book on to the surface, and finishing off with cotton wool, which rubs off all the superfluous gold-leaf and smooths it on the surface. Water-gilding (a process, however, in which no water is used) consists in covering the siu'face of metal with a thin coating of gold ; the best metal for water-gilding is either brass, or a mixture of brass and copper. A mixture of gold and mercury, in the proportion of one part of gold to eight of mercury, is made hot over a fire till they have imited ; it is then put into a bag of chamois-leather, and the superfluous mercury pressed out. What remains is called an " amalgam ; " it is soft, and of a greasy nature, so that it can be smeared over any surface with the fingers. The articles to be gilt are made perfectly clean on the surface, and a liquid made by dissolving mercury in nitric acid ABTS AKD TRADE PROCESSES. 177 fiqiia-fortis) is brushed over tliem by means of a brusli made of fine brass wire, called a " scratch-brush." The mercury inunediately adheres to the surface of the metal, making it look like silver, when this is done, a little of the amalgam is rubbed on, and the article evenly covered with it. It is now heated in a charcoal tire till all the mercury evaporates, and the brass is left with a coating of gold, which is very dull but may be burnished with a steel burnisher and made bright if necessary. In former times articles were inlaid with thin plates of gold, which were placed in hollows made ^vith a graver and melted in, a little borax being applied between. "UTien a solution of "chloride of gold" is mixed with ether, the ether takes the gold away from the solution, and may be poured oft' the top charged with it. This solution, if appbed to polished steel by means of a camel- hair pencil, rapidly evaporates, lea^-ing a film of gold adhering to the steel, which, when burnished with any hard substance, has a very elegant appearance. In this way any ornamental design in gold may be produced, but it is not very diu-able. The gilt ornaments, scrolls, and mottoes on sword-blades, &c., are sometimes done is this way. "Gilding refined gold" would appear a great absurdity, but something very like it is often practised in the process called " coloring," used by jewellers. This is however never applied to " refined gold " but to gold that is not quite so good in color as it should be. It is boiled in a liquid containing chemical substances capable of dissolving the alloy from the surface of the article and depositing a thin coating of pure gold, giving it the appearance of being made of better gold than it really is. This is in truth a species of electro-])lating, but was in use Aery many years before the electro-depositing process had been discovered. SILTERIXG LOOKT>'G-CfLASSES. Although this process is called " silvering," yet no silver is used ; the substance at the back of the glass is a mixture of tin and mercury, called an " amalgam." — indeed, the term " amalgam " applies to all mixtures of mercury with other 178 AETS AXD TRADE PEOCESSES. metals. The process is as follows : — A sheet of '• tin-foil " (tin rolled out to about the thickness of paper) the size of the glass to be silvered is placed on a perfectly level table, covered "vrith cloth ; upon the tin-foil some mercury is poiu'ed, and spread evenly and quickly over the surface with a hare's foot. The plate of glass is in the meauwhile to be made perfectly clean and dry — not the slightest speck or smear must remain. A sheet of tissue paper, also clean and dry, is laid over the surface of the merciuy, the plate of glass is placed on the paper and made to correspond viith the mercurialised tin-foil beneath. "Weights are now placed on the plate of glass to keep it firmly do^^Ti, and the sheet of paper is drawn out steadily and slowly ; as it passes over the surface of the mercury it brings away all film or dust, and the surface being left perfectly bright, adheres so firmly to the dry glass that it is not easily removed. A great difficulty is to prevent air-bubbles from finding their way between the glass and mercury. The table is now raised slightly at one end, and the superfluous mercuiy allowed to drain off". After a few houi's the tin-foil Avill be found to be completely united all through with the mercury, and will be so brittle that it can be scraped off' in powder from the glass. Great care and practice are required to silver large plates, but any one by a few trials may succeed perfectly with a piece of glass a few inches square. Glass globes are silvered inside by shaking in them a mixture of mercuiy and tin filings until it adheres to the surface of the glass, which must first be made perfectly diw and warm. SILVER PLATING. Plated goods consist of metallic articles coated with a thin plate of silver ; the metal is made of a mixture of brass and copper, which is cast into flat slabs or ingots about an inch-and-a-half thick, the surface on one or both sides is filed flat and smooth, and a plate of silver of about the thirtieth part of an inch thick, but a little smaller than the metal, is applied smoothly to it, the edges are covered all round Avith borax ground fine with water and the plates tied tightly together with wii-e. The whole is then put into AETS AND TRADE PROCESSES. 179 a furjiace and closely watched till the silver begius to melt, when it is at once taken ovit and allowed to cool ; by this mode of treatment the silver adheres so firmly to the metal that they become as one piece. It is then passed between steel rollers and rolled out to the required substance, the silver and metal both becoming thinner in about the same proportion, so that on a plate of metal, of whatever thit-kness, the silver is somewhere about a fortieth or forty- fli'th part of its thickness ; these plates of metal coated with silver ai'e worked by stamping, punching, or passing between rollers the edges of which have mouldings, curves, &c., cut on them, and tlie parts of each article when moulded are afterwards soldered together so as to form what is intended. Wires of various forms are plated in the same way and afterwards drawn out by means of draw-plates (see " Wire- drawing"). Electro-plating has to a great extent superseded this process (see '* Electro-plating"). ELECXRO-PLATIXa AXD DEPOSITION OF METALS. This art has for its objects the coating of metallic articles with other metals of more value, beauty, or durability, such as gold, silver, or copper, by means of electricity, and the formation (by the same means) of other articles by the deposition of metals, from Kquids containing them, upon moidds or engraved surfaces capable of modelling them. AV^hen the deposit forms a coating intended to be permanent, and which adheres to the article so as to be incapable of removal, it is called '• electro-plating." but when a fac-simiie of any surface is required, or a cast of a mould which may be removed, forms t!ie object to be produced, it is called " electro typing " or "electro-depositing." By way of experiment, procure two vessels, a and b, fig. 1, in one of them, A, put some dilute sulphuric acid and two j)lates, one of zinc, z, the other of copper, c, these must not touch each other, but may be separated about half an inch by two or three pieces of wood or cork, and bound round with string ; each of these plates must have a piece of wire fastened by soldering to their upper parts. In the \essel 13 put some solution of sulphate of copper and a N 2 small qiiantity of dilute sulphuric acid, and attach another copper plate to the wire which comes from the copper plate in the acid : this second copper plate is to be unmersed in the solution of sulphate of copper, and to the wii-e from the zinc plate is to be fixed the object to be coated with copper. If a medallion or other object in plaster, it should be soaked in very hot wax and then bnished over with blacklead imtil the suiiace is perfectly blackened and ARTS AXD TRADE PROCESSES. 181 brio;ht : the wire should be bound all round the margin and soldered (as it were) with melted wax to the medallion, taking care that this wax also is well coated with blacklead. It" tlie object be now immersed in the sulphate of copper solution and kept at a short distance from the plate (it must not touch it), a coating of copper will soon cover the surface and form a perfect east, which when of sufficient tliickness may be removed by filing the edge all roimd (if instead of the plaster cast a copper coin or other copper object be used, the blackleading is not required, but the GILDING KIXGS. surface must be first made clean and bright). "With the same arrangement, but using instead of the sulphate of copper a solution made by dissoh-ing cyanide of silver in a solution of cyanide of potassium, a coating of silver will be deposited, and the same of gold (if cyanide of gold be used), but these coatings will not adliere. If it be intended that the coatings shall adhere, to plate the article with sdver or gold, it should be first thoroughly cleaned, then brushed over with a solution of nitrate of mercury, washed in clean water, and put into the gold or silver solution; the nitrate of mercury will cover the copper 1S2 AETS AXD TEADE PROCESSES. article Avith a thin coating of mercury, which vnH be taken lip as the gold or silA'er is deposited, and this coating will adhere, the article being thus "electro plated." As in using the solution of sulphate of copper, a copper plate was immersed in the solution and united by the wire to the copper plate in the vessel a, so in using the solution of cyanide of silver, a silver plate must be used, and in the gold solution a gold plate, these plates being dissolved as the metal is deposited, the liquid remaining pretty much the same and serATUg for future operations. The gold and silver thus deposited are dull, but may be bmnished with a steel burnisher, all over or in parts as the design may require. In manufacturing, these processes are much modified, and powerful galvanic batteries or electro-magnets used ; in the latter case the electro-magnetic machine is oiten driven by a steam-engine and the troughs of depositing liquids contain often many dozens of articles, which are all receiving a coating at once. SOIDEEIXG A^D BEAZIXG. Tlie art of imiting metals by another metal or alloy, is called soldering (which includes '" hard and soft soldering," and "brazing"). If any metal be applied in a melted state to the surface of a piece of cold metal, under ordinary circumstances it will not adhere, but runs off" in globides, this is OTs-ing to the surface being covered with '' oxide " or rust, but if the smface be scraped or filed bright and some substance applied which will defend it from the air, and at the same time become fluid at the heat of the melted metal, then it will adliere. For this piu'pose borax is used in hard soldering and brazing, that is in soldering AA^ith metals which require a considerable amoimt of heat to melt them ; and sal ammoniac, rosin, oil, etc., in cases of soldering with '• soft solder," or solder that will readily melt. This soft solder is made of a mixture of lead and tin. and if required to melt very easily (as in soldering pewter), then some "bismuth" is added. Bismuth itself does not melt more readily than lead, but it has the property of causing other metals to melt more readilv. AUTS AXl) TKADE PROCESSES. 183 If the edges of two pieces of tiii, for example, have to be soldered together, an iron with a wooden handle and a piece of copper joined to the other end is used. This is made red-hot. and the pieces of tin being placed smoothly together and tlieir edges sprinkled with rosin or sal ammoniac, the hot iron (fii'st touched on a piece of rosin to clean it) is then applied to the joint, a piece of soft solder being applied at the same time, and as this melts it is drawn in a melted state by means of the hot iron (to which it adheres) down the joint. An excellent substance for soldering all sorts of small work, such as pieces of brass, copper, or tin, is chloride of zinc — this may easily be made by putting pieces of zdne into spirit of salt, (hydrochloric acid), and allo\\-ing them to remain as long as any eifervescence continues; tliis solution may be kept in a bottle and applied to any Oilge to be soldered, by means of a small brush or feather. Wlien iron and copper have to be " brazed," the joints are made bright, and then coated with borax ground into a paste with Avater. A mixture of brass and zinc (called spelter) in small grains is sprinkled on the joint and it is then put into the hollow of a bright fire which is urged by bellows till the spelter melts. Silver is joined by hard or "silver" solder, which is a mixture of silver, zinc, and copper, and the fusion is generally etfected by a blow-pipe, (see " Blow-pipe ") ; gold is soldered by a mixture of gold and copper. Leaden pipes are joined by having the ends to bo united scraped bright and introduced a short way one within the other, some melted solder is then poured from a small iron ladle on the joint at the same time that it is rubbed round with a piece of folded cloth greased on the surface. Joints in cisterns, &c., are generally made by scraping the edges clean with a steel scraper, and applying some Lamp-black and size by means of a brush to the parts beyond, leaving a bright space of an inch or so on each side of the joint, a ladle of melted solder is then gradually poured on the joint and rubbed down with a piece of greased cloth, the lamp-black and size preventing the solder adhering to any part but that left bright, and in this way a straight ue;it joint is produced. 184 ARTS AXD TEADE PEOCESSES. THE SMELTIKG OF METALS. All metals are got from the earth where they exist in the form of " ores" (in reality metals combined with other matters), and " smelting " is the process of getting rid of these other matters, the chief of which are sidphiu- aud oxygen. The ores when dug from the mine are generally stamped into powder, then '"roasted," that is, made hot and kept so for some time to di'ive off water, sidphur, or arsenic, which would prevent the '" fluxes " acting properly. The fluxes are substances wliich "will mix with, melt, and separate the matters to be got rid of, the chief being charcoal, coke, and limestone. The ore is then mixed with the flux and the whole raised to a great heat ; as the metal is separated it melts, runs to the bottom of the " smelting furnace," and is di'aAvn oft' into moulds made of sand ; it is thus cast into short thick bars called " pigs," so we hear of pig-iron, pig-lead, &c. Iron is smelted from '• ii'oustone," Avhich is mixed with coke and limestone. The heat required to smelt iron is so very great, that a steam-engine is now always employed to blow the furnace (before the iuvention of the steam-engine, water-mills were used for the same purpose). The smelting is conducted in Avhat is called a blast furnace. "When the metal has all been " reduced " or melted, aud run dovm to the bottom of the furnace, a hole is made, out of which it runs into the moidds ; this is called "tapping the fiu-nace." Smelting is often confounded ^\iih melting, as the names are somewhat alike, but the processes are entirely diflerent ; in melting, the metal is simply liquified, in smelting the metal has to be produced from ores which often have no appearance of containing any, as in the case of iron-stone, Avhich looks like bro^vn clay. By way of experiment let the reader take a small portion of '' litharge," which is a reddish powder, mix it with a drop of oil into a thick paste and place it on the end of a flat piece of charcoal or wood, and direct the flame of a candle upon it by means of a blow-pipe ; a slight hissing noise will be heard, and in a moment or two a small- bright globule of lead will make its appearance. .ESEUAL FOUXDKy, AVJOLWiCU AKoEXAL. FOUKDIXG. Fouuding is the art of casting metals into various forms by means of moulds. The products of smelting are of a coarse kind, and have to be remelted before the process of casting or founding begins. Before any article can be cast in metal, a pattern must be formed in wood, clay, or other suitable substance. The floor of the foundrV is made up of sand and powdered charcoal to tlie depth of several feet, serN-ing to imbed the moulds which are used, and in several places deep pits full of the same material are formed for large castings ; an iron frame, corresponding to another like it, and capable of being united to it by pins and sockets, is used to contain the moulding sand juid pattern. Let it be supposed, for simplicity', that a camion ball has to be cast, one of the frames is filled -w-ith moulding sand moist enough to bear a good impression, and a ^^s^ Gr>' rorxDKT, TrooLwicn aesexax. cannon ball pressed half-way in ; the surface is now dusted over with red ochre (to keep the upper half from sticking to it), and the other frame applied and united with the lower one, this is now filled "mth the sand and beaten or trodden down firmly. On separatins: the two and remo^Tna: the pattern, there is an impression of half a ball La each half of the mould, and when these are again put together there is a hollow corresponding to the pattern used. There are, however, two things more to be attended to, one is to have an opening for the melted metal to be poiu-ed in, the other an opening for the air to escape, and this is eftected by attaching to the pattern tAvo pieces of wood or iron which project; upwards through the iipper half of the mould, and when this is carefully lifted iip two holes appear which on being united to the lower halt" lead into the round hollow. "When the moulds are ready they are put into a room heated bv means of stoves, and thoroughly dried. They are then biuned in the floor of the foundry, leaving the holes for pouring the ARTS AND TRADE PROCESSES. 187 metal exposed, channels being formed in the sand, so that when the furnace is " tapped " the melted metal may flow down these and fill the moulds. Some forms are so complicated that the moulds have to be made in several pieces, and the ingenuity of the foimder is taxed to the utmost to produce those required. CASIIXG PLATE GLASS. GLASS BLOWING AXD CASTI^'G. Grlass-blowmg requires great practice and manual dex- terity, for the material used being red-hot cannot be touched with the hands, and lias to be ver\- rapidly worked, or it becomes cooled and hard ; to any one unused to work with it, it is the most unmanageable material conceivable, but by practice the glass-blower contrives to produce almost any form required, and of a size quite astonishing — as. for instance, the globular bottles seen in druggists' windows, 188 ABTS AXD TBADE PROCESSES. which often hold twelve gallons, also glass shades, which are of an luiiform thickness, and two or three feet high. This is all done by means of a hollow rod of iron called a " pimtil," on the one end of which a mass of molten glass is collected (fig. 1). and the workman blows into the other, at the same ^A;; time tu rnin g the tube rapidly round in his hands (fig. 2). "\\Tien the kind of glass called " crown-glass " has to be made, the end of the iron tiibe is put into the pot of melted glass, and turned round till a ball of it is collected about the size of one's head, the workman then blows in at the other end, still turning the rod in his hands; it has now the appearance presented at fig. 3. An iron rod is stuck on to the side of the globe opposite to the "puntil," which ARTS AND TllADE PROCESSES. 189 is then pulled suddenly away, leaving a round hole. The globe of glass is again made red-hot, and spun round rapidly, FIG. ». the hole increasing in size until it resembles fig. 4. By con- tinuing the rapid twirling of the rod, the hole opens ^nder and wider till at last one broad sheet is produced ; it is then separated from the rod by putting a drop of cold water at its j miction with the glass, which causes it to crack across at that part. It is now about six feet in diameter, perfectly round and flat, and when cold it is cut into halves and packed ^^dth straw in a " crate " for carriage. The Imot of glass often seen in kitchen or stable windows, is the part in the centre of the glass where the iron rod has joined it, and is called the "punty." Sheet-glass is commenced in the same way as crown, but instead of a hole being made the blowing is continued till a great round ball is formed, the rod and this ball are then 190 ABTS A>'D TBADE PHOCESSES. Sprung roimd at arm's length — a hole being sunk in the ground for the purpose — which causes the globe to become elongated, as in fig. 5. It is then laid upon an iron table, and rapidly slit up, the compressed air escaping from within PLATE trX_S.io CA;II>G. BK1>G1>G OUT THE POT. opening it out into a broad sheet, which is instantly cut square while yet soft. Plate glass is cast by pouring it from a large pot ou to a lat iron table with a ridire all round it, and on which an ARTS AXD TEADE PROCESSES. 191 iron roller is so placed that when the molten glass flows on the table it passes ever and flattens it out to the required thinness, which is regulated by elevating or depressing the ridges at tlie sides of the table, made moveable for that purpose (the process is illustrated by the cut at the head of this article). When cold, the surfoce of the plate is ground perfectly flat and even by means of emery-powder (tig. 6), and then polished with a cloth rubber charged with a fine V?^^~ red oxide ot iron called "crocus" (fig. 7). The grinding and polishing are both performed by steam machinery. B>)ttles, and such like articles are either simply blown into the form required, or into moulds made to close upon the ball of soft glass, and again open when the required form has been given (fig. 8). Many articles of glass are cast, or *' struck-up " by compression in a mould, and are otten made to resemble cut-glass articles, but they are much inferior in appearance. The best articles of glass are first blown, and afterwards cut and polished (see '"Glass-cutting"). Of whatever kind the article of glass mav be, it is so brittle that the slightest blow would break it, a bad quality which is got rid of by a ])rocess called '' anneal- ing." Tliis consists in placing it while ^^^- ^• (piite hot on the floor of an oven, which is allowed to cool 19S AETS AXD TBADE PEOCESSES. very gradually indeed. This slow cooling takes off the brittle- ness ; and aiiicles of glass TveU annealed, will scarcely break with boiling water, and are very much tougher than others. GLASS- CUTTI^fG. The kind of glass generally used for ornamental cutting is flint-slass. Decanters, wine-glasses. &c.. are also made of it ; it is very bright, white, and easily cut. Glass is cut by means of wheels of differeut sizes and materials, turned by a treadle, as in a common lathe ; some , are made of fine sandstone, some of iron, others of tin or copper : the edges of some are square, some roimd, and some are sharp. They are used with sand and water, or emery and water, but stone wheels are used with water only. The ijlass-cutter also uses rods of copper with knobs at their ends, for making roimd indentations ; these turn on their axis, so that the end cuts a round hollow in the glass. The work is at first cut roughly, afterwards smoothed off with the sand- stone or tin wheel (the latter has to be smeared with emery and water) , and finally pohshed by a wooden wheel with finely -powdered piunice-stone applied to its edge, and moistened with water. The glasses for spectacles and optical insti'iunents are cut by concave or convex moulds of brass moistened ^dth emery and water, and polished by means of a mould of pitch Avetted with crocus and water. Great art and accuracy are required to grind the glasses for optical instruments, especially ver^- large or very small ones, as for microscopes, the various " powers " of which constitute their chief expense — one of the sixteenth of an inch in diameter costing about twelve pounds. GLASS-CriTIXG. loji.L.VXi.Si. BRICKLATIXG. Nearly all houses are biiilt of bricks, as they are less expensive thau stone, and more durable than wood, besides being less liable to be burnt. AVaUs of brick may be formed X^X^.. ^\\\\\ \ 1 ''!'l tl ; * 1 — r FIG. 2. of any required thickness, and as tlie length of a brick is twice its breadth, they admit of being so laid that the wall 191 AETS AND TRADE PEOCESSES. sliall not part in pieces, •nliicli would be the case if laid as in fig. 1, as the seams of mortar run continuously through the wall, which in bricklaying is always avoided, by difterent methods. Formerly bricks were laid in what was called "English bond" (fig. 2), but this is not now used, " Flemish bond " (fig. 3) having super- seded it. The mortar with Avhich bricks are laid is made of lime and sand, mixed with water to a convenient con- sistence ; it sets quickly, hardens with age, and resists the action of rain and time. The ordinary mode of laying bricks is to stretch a line from end to end of the course on which they are to be laid : the surface of the under course is _f i 1 I' h TIG. 6. spread for a short distance with mortar, and the bricks intended to form the outer surface of the wall are laid first, in an exact line with the cord, the "pliunb" (fig. 1) being frequently used to ascertain if they are perpeudicidar. The •' plumb " is a piece of board -n-ith a notch at the centre of the top, and a hole, also in the centre, near the bottom ; a AET3 AXB TRADE PROCESSES. 195 piece of cord is passed through the notcli, witli a leaden ball attached, which swings iu the hole as the plumb is placed at tlie side of the wall. The ball of lead just falls in the hole if the wall is upright, and in this way a wall may be built to any height, exactly perpendicular. The corner of brick- work where windows occur, is called the " arris," and has to be made upright both in front and at the side. When very thick walls are to be made (as in railway cuttings), the outer suriace and back of the walls are laid in the usual way, the space between is filled with a layer of bricks, and thin liquid mortar is poiu'ed on and scraped about with a sort of hoe till the spaces between the bricks are all filled up and the siu-face left level, when another course is laid in the same maimer. Fig. 5 is a trowel, or instrument used to take up and spread out the mortar, and fiiif. 6 is the hod, in which the labourer carries supplies of bricks or mortar to the spot where the bricldayer is working. STOXE CUTTING. Some stones, as " Bath stone " can be cut Anth a common toothed saw, and are but little harder than chalk ; others, as FIG. 1. FIG. 2. marble, Portland stone, etc., require to be cut witli a fiat blade of iron stretched in a frame and having a supply of sand and water. A man sits in a shed having this heavy saw suspended from two poles, and balanced by a j)iece of stone swung over a pullev ; he alteruatelv pushes and puUs o 2 sio:.'i;-cLii"i>'G. the frame, allowing the water to trickle into the seam as it forms, the sand being rubbed between the edge of the saw and the stone as the saw is moved backwards and forwards, slowly cutting the stone (see illustration) . Bv this slow and tedious process building stones are cut into squares, slices, slabs, or any other form required. Granite is too hard for even this slow process, and after the pieces are chosen as nearly as can be got of the size and shape required, they are worked with a heavy iron pick (fig. 1), which at each blow strikes oif a Little piece not bigger than a pea, by which method the stone is shaped into the form reqviired. Smaller cuttings of stone for building purposes, such as carvings. &c.. are formed by the mallet and chisel (fig. 2), the work being finished with a rasp or steel scraper. APPARATUS A>'D :\[ACIIIXERY, BEAM OF STEAM ENGINE, WOOLWICH AESEXAI,. STEAM-ENGINES. The great improvements in machinery — whether for looms, locomotive engines, or steam-ships, for forging anchors, boring cannon, rolling out and rivetting iron plates together for tubular bridges and boilers, or any other kind of work — are chiefly owing to the wonderful ease with which these machines can be driven by the power of steam. It matters not whether the object to be wrought is the liead of a pin, or the crank of a steam-ship, it is done with both delicacy of toucli and power of arm, a 1 1 1 H i : ' h i ^ 1 .( Sv S FLT-W Hi EL, WOOLWICH AESEXAL. himdredfold beyond \rliat coiild be effected by hand in the same time. The motive power of steam is derived from the property which water has of being expanded into vapoiu- when heated to a certain degree, and of again resuming the form of water when cooled : this moreover takes place in the most easily manageable manner, and either by degrees or suddenly, according as the heat and pressiu-e balance each other : moreover water, being easily obtained, and in sufficient quantity for the piirpose, in all places where machinery is required, can always be applied. Before the use of steam, Avind, water, horse, aud hand power were APPAHATUS AND MAClIiyEEY. 199 chiefly in use ; water-mills were, of course, only erected in those situations Avhere a good supply of water could be obtained, and this even often failed in dry weather ; wind- mills also depended on that uncertain element. Horse and liaud powers are limited in their extent, and are moreover very expensive. The first attempts at a steam- engine were those in which the steam was only used that bv its condensation a vacuum might be formed in a cylinder imder a piston, so that the weight of the air should cause this to descend ^^^th considerable force — 15 lbs. on the square inch. The piston was balanced by a weight, so that the steam might raise it Adth scarcely any pressure ; the steam beneath the piston being condensed by a stream of cold water, the weight of the aii' again forced do\\Ti the piston into the vacuum. This therefore was not a steam but an air-engine, as aU the power exerted was derived from the weight of the air, and the steam merely used to procure a vacuum. After this came the low-pressure or condensing engine, and then the high-pressure or non-condensing engine, both of which are now used, the former in marine engines and the latter in locomotives. The steam-engine consists essentially of a boiler or steam- generator, with a furnace adapted to it, connected by a steam-pipe to a cylinder having a piston working accurately in it, and valves so contrived that the steam shall enter alternately above and below the piston. In the condensing engine, each compartment, above and below the piston, communicates Avith the condenser — the vessel in which the steam is suddenly condensed by cold water — and the valves are so arranged that when the steam enters above the piston, the space below is opened to the condenser, and is therefore a partial vacuum ; by the time the piston is driven dovra by the force of the steam above it, the space is shut off from the condenser and opened to the steam-pipe, while the space above is shut otf from the steam- pipe and opened to the condenser. In this way one side of the piston is alternately pressed by the steam while there is a vacuum on the other side. In the non-condensing engiae the space above and below the piston is alternately 200 APPAEATUS A>'D MACH1>'EET. pressed by steam at a gi'eat degree of tension ; while at the opposite side of the piston, the space is opened to the air by a valve. These valves are what are called " sliding valves," being both in connection with the same action, which shuts one while it opens the other ; that is, when the piston has nearly descended, it slides the valve which shuts off the steam from the space above and opens it to the air, the same action opening the steam-valve below the piston and shutting it from the air. In this kind of engine the piston is moved simply by the power of the steam, which first presses it do\\ni and then presses it up again, and as FIG. 1. BOILEES, WOOLWICH AESEXAL. the steam escapes at each stroke of the piston, and has to be at a great tension or pressure, a large and rapidly-formed supply of steam is required. In the locomotive and other high-pressure engines this is effected by having a great number of tubes passing through the boiler leading trom the fire-place to the flue, so that the fire and heated air shall pass through them before reaching the flue, and consequently, as these all pass through the water in the boiler, producing a very rapid generation of steam. Of the various forms of PIG. -. iiOil-iiiii, WOOLWICH AKtifiXAI.. lioilers, the most simple was that in wliieh the heat was merely applied to the lower part (fig. 1) ; next may be uamed the wagon-head boiler, iu which tlie Hue passed all roimd ; some were made with a cylindrical flue passing though the whole length, and some with two (fig. 2). Of whatever form the boiler may be, it should be strong enough to well resist the pressure of the steam, but to make this sm*e, a contrivance called a safety-valve is always used; this consists of a valve held down by a weight, which would be raised bv the steam if it should press so hard as to endanger the boiler in the least degree ; when the safety-valve is forced up, the steam escapes and the pressure is taken otf. Most steam engines require the up-and-do\vn motion of the piston to be conterted into a circidar motion, and this is efieeted by means of a " crank," (see " Cranks ") ; but this circidar motion needs in most cases to be regidated bv a tly-wheel which is so heavy, that upon being set in motion it coutiuues to revolve for a time by its own weight, so that 202 APPARATUS AXD MACHINERY. the intermitting pidls exerted by tlie piston-rod on the crank are blended into one continuous action (see cut) ; but in steam-ships, and locomotive engines, fly-Avheels cannot be used. In these cases there are two cylinders and pistons, each fixed to a crank formed in one axle united to the two wheels, and these cranks are so arranged that the greatest power is exei-ted on one when the least is exerted on the other, and for this purpose they are placed so that when one crank is upright the other is horizontal. The stroke of the piston-rod is not alwa_ys made to act directly on the crank, but has a "beam" interposed working on bearings in its centre, hence the term beam-engine (see cut). This beam moves the crank at the opposite end to that which is moved by the piston and at the same time Avorks the air-pump, feed-pump, and cold-water-pump, by means of jointed rods. In those engines Avhich have to perform luiequal work, and in which sometimes a great di*ag is suddenly removed from the engine, some contrivance is necessary to prevent the too rapid motion which would ensue, to the great risk of damaging the engine ; this is effected by what is called the "governor;" a contrivance by which a part of the steam is struck ofl" when the action is too rapid, and again let on when it has diminished. This arrangement is shown in fig. 3 ; the two hea^y iron baUs swing roimd as the engine works, and the faster they revolve the more they tend to separate, from the natm'al tendency to fly off called " centrifugal force," and in separating they bring the other ends of the rods to which they are attached nearer together, and so push up a collar, a, attached FIG. 3. to the levers which tui'n oft" the steam-tap ; and as the action subsides the balls sink do-«ii together and the collar also, the steam being thus turned on again. In order that the pressure of the steam in the boiler may be knoAMi, a " gauge " ArPAUATUS AXD MAClITXERr. 203 is used, which acts on the principle of the barometer, con- sisting of a column of mercury which is pressed up by the force of the steam, the height to whicli it rises indicating the pressure. With respect to the details of the steam- engine, they are too various and complicated to be enumerated or described here ; but the motion — being regular, continuous, and powerful — can be applied to almost any sort of work by being adapted to the machine suitable for such work, and which receives its motion from the steam-engine, the same as though it were Avorked by water or by hand. BOILEllS. Boilers are vessels in which fluids are boiled or heated, and are ahnost of every form and size. Some boilers, such as those attached to steam-engines, are more strictly called " steam generators," as they are constructed solely for the production of steam at the lowest possible expense of time aud fuel, and also to resist the pressure which the steam exerts at high temperatures ; these boilers are not only used to produce the steam for the motion of engines, but are extensively used in its production for heating evaporating- pans and boilers (in the strict sense of the Avord), and also for warming and ventilating buildings. They are more particularly noticed under the liead " Steam Engines." ]3t)ilers for all purposes were formerly made of metal (usually copper or iron), aud Avere exposed directly to the fire intended to heat their contents, but since the properties of steam have been more fully recognised, it is now very frecpiently employed for heating boilers — especially where a heat at or beloAV the boiling point of water is required. There are great advantages arising from this plan, one of which consists in doing away with the risk of the materials in the boiler being burnt. Some boilers are now made of Avood, having steam-pipes running through them, and in those cases in Avhich the admixture of Avater is no detriment steam — in the form of jets — is throAvn directly into the fluid to be heated, Avhich very quickly raises it to tlie boiling point. Boilejs of cast-iron, lined Avith platinum or enamel, 20i APPAEAXrS A>'D MACHIXERT. are also used for various purposes, as the condensation of acid substances, &c., which would act on most metals. Glass and glazed pans, too, can be used with a steam apparatus, without any danger arising from breiUvage, which would frequently occur if they were directly applied to the fire. FUE>'ACES. Furnaces are fire-places constructed to serve particiolar purposes, and are chiefly of two kinds, " Wind furnaces " and " Blast furnaces." Of the first kind the common house grate is an instance, of the second the blacksmith's forge. The fire in a wind furnace is more or less shut up, so that the draught of air entering it shall pass from the ash-pit right up into the fire, and thi'ough it into the flue or chimney — the latter being tall, and of certain proportions, so as to ensure the requisite draught. These furnaces are used where heat of the very highest degree is not requii'ed, as in glass-houses, pottery-kilns, &c. The " Eeverberatory PIG. 1. FIG. 2. furnace " is a modification of the wind fiu-nace, and is iised to throw heat on to the surface of substances, as in roasting ores of metals, to drive ofl" the sidphur. arsenic, &c., or in the making of soda, litharge, and other processes where the admission of hot air with the flame is either beneficial, or at least not detrimental ; fig. 1 shows the construction of this kind of furnace. Blast furnaces are for the .production of ArPAHATIS AND MACniXERY. 205 the very highest degrees of temperature, and in tliese the air is forced into the fire by blowing machines or bellows, often worked by steam-engines ; such furnaces are used for the smelting and casting of iron, &c. (fig. 2). A good blast furnace for small purposes may be made by two crucibles — those made of coarse blacklead and clay, and called " Blue pots," are the best — one placed inside the other, the outer one having a hole at the lower part for the nose of the bellows, FIG. 3. the mner one having the bottom cut off and a grating of iron put in to lodge just above the lowest part ; the space between the two should be filled with powdered fire-brick or broken-up crucibles (fig. 3). BELLOWS AXD BLOWING MACHINES. Tlie common bellows is the most fimiiliar form of blowing machine. It consists of two boards bound together with leather, hadng folds so arranged that the upper board may be raised or depressed, and the whole is made air-tight ; in the lower board is a hole with a leather flap-valve opening inwards. "When the upper board is raised, the air rushes in at the hole, pushing up the valve, and when the board is lowered the air presses the valve down, and so shuts it close, it has therefore no exit but at the nose of the bellows, from which it passes out. Blacksmiths' bellows (fig. 1) are made double, for the purpose of keeping up ii 206 APPABAirS A>'D MACni>T:BT. continuous stream of air, iustead of the separate puffs pro- duced by the common single bellows. The arrangement of the double bellows is as follows: — There are tliree boards bound together with leather folded as in the common house bellows ; the board in the middle is fixed, and to this the nose is fastened, but it opens only into the space above ; the upper and lower boards are imited to the middle FIG. i. one by a hinge, and are capable of being moved np and down ; the middle and lower ones have each holes and valves opening upwards as in the common bellows, and when the lower board is raised it presses the aii- in the space between it and the middle board through the hole iii the APPARATUS A>'D MACniXZEY. 207 latter, into the space between it and the upper one, and so raises it ; this has a heavy iron weight phiced on it which makes it sink do%\'n and force the air out through the nose. While this weight is sinking the lower board is pushed do^\Ti, and is ready t-o force a fresh quantity of air into the upper space, so that one continuous stream of air issues at the nose of the bellows. The handle is iixed to the lower board, and generally has a cord uniting it to a wooden handle, which is worked like a punip-handle (fig. 2). For large furnaces, blowing machines of various kinds are used, generally con- sisting of a pair of large cy- linders ha\-ing pistons worked in them by steam power, and pumping air into a large air-chamber, ii-om which it proceeds in three or four pipes to the furnace, or sometimes to nume- rous furna<;e3, eacli having a tube and stop-cock by which 208 APPAEAXrS AXD MACHIXEET. the "blast " may be turned on, similarly to gas or water, the air-chamber being always kept filled at a great pressure by the cylinders, and furnished with a safety-valve to pre- vent the pressure bursting it. There is another kind of blowing-machine, consisting of a fan wheel turning very rapidly in a round box (figs. 3 and 4), from which a tube proceeds, and having holes in the sides to admit the air, which is thrown forwards by the lans of the wheel. SCilEVy SIEAil-VEiSEL. SCREW PEOPELLEES. These are instruments placed at the back part of steam- vessels for the purpose of propelling them through the water. Fig. 1 will show the position they occupy, and fig. 2 the shape of the propeller. When first used, they had one or two entire turns round the axis, but are now made with two blades, each forming about one-sixth part only of one turn, and this is found to give more power with less friction. The propeller is turned rapidly round in the water, from FIG. 1. SCUEW STEAM-VESSEI,, SnO\VI>G THE FAX. which it meets with resistance in a direction perpendicular to the surface of its blades, but as this is oblique to the direction of rotation the force is exerted in two directions, one directly opposes this rotation, and is over- come by the power of the steam-engine, the other is in a direction towards the ship, overcoming the inertia of the vessel and the friction and resistance of the water, so that the ship is moved along, and the propeller M"inds its way through the water in a spiral direction as an ordinary Screw does through the hollow screw made to fit it, the vessel travelling at a speed proportionate to the screw's revolutions. 210 APPAR.VTIJS a:s'd MACIII>'ERY. AXCIIOES. These ponderous instruments are used for the purpose of securing ships and other vessels, that they niay not be driven onwards by the wind or tide. They are attached to a strong rope or chain, calle 1 the " cable," and when not in use are kept swung at the fore-part or bow of a sliip, the cable being FIG. 1. FIG. 2. wound round an apparatus called the capstan, which serves to let it out or draw it in. Anchors are made of ii'on, and are of the form delineated in fig. 1. The straight part from the ring to the bend is called the " shank," the curved part is made up of the two " arms," and the centre where it joins the shank is called the " crown." At the end of each arm is a plate of iron of triangular form, called a " fluke," and crossing the shank close to the ring is the " stock," which is made of two pieces of oak bound to- gether with iron bands ; some- times it is made wholly of iron, as in fig. 2, in which case it runs through a hole in the shank, and has one of its ends curved for the purpose of FIG. 3. APPARATUS AND ilACllINEEV. 211 packing more closely and saving space (fig. 3). The anchor, when let fall from the ship, carries the cable with it, and generally tails on the crown, then tilts over so that the stock lies Hat on the bottom and one of the flukes sinks in to a considerable depth by its great weight ; when the ship FIG. 4. drags at the cable it lifts up the stock and throws the whole weight of the anchor on the fluke, and makes it sink com- pletely ; any further pull must bring up a large piece of the earth before it can be moved. In " weighing " anchor, that is in pulling it up from the bottom to bring it on board again, the cable is slowly wound up by the capstan, and as the cable is shortened the ship is dra^vn along to a point nearly over where the anchor rests, when — the pull at the cable continuing — the shank is raised into an upright position, and tlie fluke and arm, instead of dragging up a great piece of eartli, remove but a small portion, as may be seen by the dotted lines in figs. 4 and 5, which show' the earth to be removed before the anchor can be drawn from its hold. p 2 212 APPAHATUS AXD MACHIXERY. Large vessels carry four auchors. the " best bower," the "small bower," the "sheet," aud the "spare" anchors, their size depending on the size of the ship, the rule in the Eoyal Xavv being a hundi-ed- weight for each gun ; so that an eighty-gun ship carries auchors of foiir tons each, or eighty hundredweight. Anchors are made of the best aud toughest wrought ii"ou, and tlie greatest care is necessary in forging them in order that there may be no flaw in the welding, for a ship may be lost by an anchor breaking. CHAEs'S. Chains are made up of separate links of rigid metal which having no flexibility in themselves are yet so united that each shall move freely on the next links to it, and thus produce a flexible whole. For ornamental purposes there is almost an endless variety of patterns, as mav be seen in jewellery- work — but for the purposes of business and machinery there are chiefly but two, the ordinary, as fig. 1, and that which will only bend in one plane, as in fig- 2 — this is chiefly made use of in passing round wheels, as in clocks. Chains are used where rough wear is required, in which case rope would be rapidly worn through. Cables of chain are now much more generally APl'AltATUS AND MACHINERY. 213 used than hempen ones, as they arc more to be depended on, take up less room, and are not so liable to be cut or worn by rough rocks at the bottom. In chain cables a "stay" is placed in every link (fig. 3), FICJ. 3. wiiich greatly increases its strength, but the best form of chain cable is shown at fig. 4 ; in this the links are somewhat angular, and the stays longer. Chains are chielly made by machinery ; the rods are first drawn out of the proper size, pieces of the required length are then cut off" and bent to the right form, and the stay and this link are then both made white hot, placed in their right position, and welded together by pressure. CRAXE3. These machines are used for raising heavy bodies in a perpendicular direction. They are of various forms suitable for almost every purpose, and to most of them are adapted two or more wheels with teeth, one small and one large, for the purpose of ob- taining power at the expense of time (fig. 1) ; the small wheel is turned by a windlass, and turns the larger one very slowly but with great power. The *'"• '■ common warehouse or cellar crane is generally an ircn i vr-j>J7 /> J^~ frame with two pullevs, and the arrangement shown at fig. 1, which is usually inside the '' warehouse, while the crane is outside to raise goods from carts, &c., into the floors ahove (fig. 2). Cranes at the sides of canals or rivers for landing goods are sometimes made as figs. 3 APPAEATVS A>'D MACH1>ERY. 215 and 4 ; in the last there is a heavy stone placed to balance the " " What is called the "jib weight at the end of the crane crane" is often '"rigged" up on shipboard for shipping and unshipping goods (fig. 5). Cranes for very lieavy purposes have been made upon the tubu- lar principle and consist of iron plates rivetted together so as to form a hollow curved crane, similar to the hollow girders used in bridges. AV'here goods have to be brought from one particular spot to another, as in fig. 6. the swing crane is used. Amongst cranes may be named the hvdraulic lift : this is exactlv FIG. 6. similar to the hydraulic press, only applied in a difiereut manner, and is used to lift very heavy weights but short distances, as for raismg heavy goods on to railway trucks, &c. C BANKS. Cranks are bends in the axle of any part of a machine by which an up-and-down motion is converted into a circular or rotatory one, as in the com- mon knife grinder's machine ; in this arrangement a fly-wheel is necessary to continue by its momentum (tendency to go on) the motion begun by the up- ward and downward action of the treadle, piston-rod, 'D MACHIXEEr. holes made to correspond, when the powder falls through into the percussion caps, each one of which thus receives a definite charge. The next process is to press it dcwn into the cap, so as to prevent it falling out. For this purpose the plate full of caps is removed to a machine (fig. 5), having a row of little stoppers, which are moved rapidly up and down, the pressure being exactly regvdated by flat 232 APPARATUS AXD ilACHIXEEY. leaden weights, suspended so as to give only so much pressure as \v\R consolidate the powder, without exploding it. They are next removed to a thiixl machine called the •• varnishing macliiue " (fig. 6). This has a trough of varnish, made by dissohing shellac in spirits of wine, into which a row of wires dip, and by a turn of the hand convey the minute portion of varnish on their points into the caps, row after row. This varnish dries in a few minites, and causes the fulminating powder to adhere ; the caps are now complete. The old form of caps was a simple short cylinder, but it is fotind better to allow the four little flaps to remain on, that the right end may be distinguished and instantly placed on the nipple the proper side downwards, which cannot otherwise so readily be done in the dark, and when the hands are benumbed with cold. PUMPS AJfD FIEE EXGI>'ES. Pumps are used for lifting fluids above their level into some higher situation, such as from the hold of a ship or FIG. 1. riG. 2. from a well. Fig. 1 shows the different parts of a common "lifting pump;" a a is a cylinder, b a piston rod or " plunge," c tlie sucker made of leather to fit nicely the cyliutler, d a valve in the sucker to open upwards, e a valve fixed to the cylinder, also to open upwards, f a box with a spout. The piston being raised by lowering the handle of the pump, a partial vacuum is formed below the upper valve, which shuts down directly the piston is raised by the pressure of the air ; this vacuum causes the external air to force the water some way up the tube g. On the piston descending, the lower valve is forced down and the upper one opened, this keeps the water where it is and allows the piston to descend without forcing the water down again, and on its being raised a second time the upper valve shuts and the lower one opens, the water being drawn up still higher, and this takes place till the box at the top is full to the spout, when it runs out. The air- pump is on the same principle, and is generally made Avitli two cylinders worked by means of a " rack " and Avheel (fig. 2) ; this is only to save time, instead of pumping water it pumps out air from any vessel called a " receiver," because it receives any object to be placed in a " vacuum," that is to say a partial vacuum, for the air-pump cannot produce a vacuum, as the air is only partly removed by 234 APPAEAXrS AND MACHINEET. each stroke of the piston, leaving the air more rarefied inside ; and although each stroke of the piston increases the rare- faction, yet it cannot get all, as it merely takes part, and always leaves part. Fire and garden engines are only applications of the pump to dilferent purposes. The fire-engine has generally two cylinders and pistons, and has moreover an air-chamber for the purpose of making the stream of water continuous. It acts in this way : — The water is forced by the power of those who are pumping the engine into a vessel air-tight and full of air, having an opening which joins the " hose " at its lower part ; the result is, that as the water is forced in faster than it can well escape, the air above it — becoming greatly compressed, and by its expansion between each stroke of the pistons — forces the water out, and so continues the stream or jet. Fig. 3 shows this air-chamber ; a joins to the hose c, and & is in imion with the forcing-pumps of the engine. The air is represented as it would be compressed to about half its bulli, for it at first filled all the air-chamber down to the openings. TALTES. Yalves are contrivances to admit the passage of fluids or gases by their own pressure in one direction, and in such a manner that the same pressiu-e shall of itself prevent their return or passage in the opposite direction, as in fig. 1, which is the piston of a common pump. There are almost imnimerable varieties of valves, one consists of a ball of metal fitting into a cup which has a hole at the bottom (fig. 2) . Another (fig. 3), is a plug of a conical shape fitting in the APPARATUS AND MAClIiyERY. 235 same way, and having a rod affixed to the top which passes through a hole iu a piece of metal so as to guide it iu its FIG. 3. ascent and descent ; this is the kind of valve used as a "safety-valve" in steam boilers, but having the pressure regulated by a spring or weights. Figs. 4 and 5 are representations of a kind of valve which forms the piston itself, and is very iiseful as a piston for a square wooden tube for temporary purposes, as on board ship, where any number may be fitted up at little trouble, time, or expense. There are many other valves besides these, as the sliding valves of steam-engines, &c. 236 APPAEATUS AXD 3J:ACHI^'EET. WHEELS. Scarcely any kind of machinery can be constructed without wheels of some kind — they serve almost numberless purposes. The fly-wheel (fig. 1) serves to produce a con- tinuous motion, from its size and weight gi^'iIlg it a tendency to go on, and in this way causing it to till up the intervals of unequal action, as in the ascent and descent of the piston in a steam-eugine. The toothed-wheel serves to PIG. 1. FIG. 2. give motion to other wheels, and this at a certain rate either greater or less than its own, according to its size, and consequently the nimiber of its teeth ; thus a wheel with a hundred "cogs" or teeth united to one \\-ith but fift^^, causes this to go round tndce while the larger one passes round but once ; but a large wheel turned round by a small APPARATUS AXD MACHINERY. 237 one, although it moves more slowly yet does so with increased power just in proportion to its slowness (fig. 2). The bevel-wheel (fig. 3) is used to change the direction of a shaft, and for all the other purposes of a toothed-wheel, from which it dift'ers only in the position of the teeth or cogs. Wheels are sometimes made to answer the purposes of bevel wheels, by having the cogs on the surface of the one wheel, and the other as an ordinary toothed-wheel (tig. 4). The ratchet-wheel (fig. 5) is a wheel with it? teeth pointing in one direction like the teeth of a saw, and into Avhich a tongue of iron is made to fall, so that the wheel can only be turned in one direction. Tliese wheels are used where the machinery is liable to rim back if left, as in the "crane," &c. The capstan (fig. 6) is a kind of ratchet wheel, and is so made that long spokes may be placed in the holes, to be moved round by men, and taken away when out of use ; it is a very powerful piece of machinery, and is used for "weighing anchor" (see "Anchors"). The pidley (fig. 7) is a series of wheels used to increase power by diminishing the rate of movement ; they are much used in the rigging of ships, and are then called " blocks." There are different ways of connecting wheels so as to communicate the motion of one to another ; they may be toothed as before described, or a "lathe-band" mav be passed over them. This may be either round or cord-like, and made of cat-gut, or flat and made of leather or gutta- percha. This mode of producing motion is very uaefid 238 APPAEATrS AXD MACHIXEET. where evenness and smootlmess of action are required, or where the wheels are at a considerable distance apart ; they have their ends united so as to form a ring, or endless band, and are sometimes used to communicate motion to a great many wheels, as seen in fig. 8. The ri eccentric- wheel has its axis out of the centre ; it is used for the same purpose as a crank, but the action is more continuous and even. While the crank is most frequently used to produce a circular or rotatorj- motion from an up- and-do-s^-n motion, the eccentric-wheel is more commonly used to produce an up-and-do'ftTi motion from a rotatory one (fig. 9). Wheels take almost every variety of form, FIG. 9. FIG. 10. and are not, in some cases, even round ; in winding yarn on to bobbins, where a motion is required of a constantly varying rate, two elliptical wheels are made to act on each other, the end of one being approximated to the centre of the long axis of the other, (fig. 10). APPAR.VTUS VXD MACHINERY. 239 Wlieels for carriages are used to diminish friction, by causing the "tire" or smooth outer edge to roll upon the surface instead of being rubbed ; all the friction in wheels is in the centre or axle, which being turned smooth, and greased or oiled, works very easily. Carriage wheels are made to revolve upon a fixed axle, and each wheel revolves independently of the other, but in railway-carriages and engines, the wheels are united in pairs, and the axle revolves with them, the weight being boi'ue outside of the wheel on a small part of the axle which projects. The various parts of a wheel are the box or " nave " which is the centre part, the " spokes " or those bars which connect it witli the centre edge or felloes, and the " tire," an iron band binding the whole together. Wheels for gun-carriages are made at Woolwich Arsenal by machinery. The following is a description of them, taken from the " Times " newspaper : — " Here a few imskilled labourers supei-intending the machines produce forty complete gun-carriage wheels a day, though all their component parts are made of the hardest woods — viz., elm for the naves, oak for the spokes, and ash for the felloes. The novelty here was the new mode in which a wheel is fitted together. Instead of by hand, as formerly, the pieces are all laid together on the ground, and of course in a circle, around the outside of wliich are six small hydraidic rams, with the head of the piston of each curved so as to form a segment of a circle touching the outside portion of the wheel. One small steam-engine pumps the water into all these ynth an equal pressure, which, as it increases, forces the felloes into the spokes and the spokes into the nave of the wheel, with such force as to compress the whole, by a strain of 250 tons, into the solidity of one piece." Paddle-wheels are made to revolve with their lower part in water, and are furnished with a series of short boards fixed to the tii-e of the wheel, which is generally double, that they may be better held on; these boards or paddles take a great hold on the water and cause the resistance which is necessary to move the vessel. The wheel of a water- mill is constructed in the same way. WATEEMILLS. Watermills are those kind of mills, the motion of which is derived from the flow of a stream of water against the lower part of a large wheel, provided with paddle-boards similarly to the paddle-wheels of steam-vessels ; or else by the weight of a stream of water falling against the upper part of the Avheel from a spout or troiigh ; the former of these is called the imder-shot, and the latter the over-shot mill. The former is used where there is a large body of water flowing at a snfliciently rapid rate, and the latter kind where there is but a small supply, the whole of which is often used for drivdng the mill; but other circumstances, of position, &c., may determine which shall be used. The large wheel being thus cbiven round, any kind of machinery may of course be attached, according to the nature of the work to be done. Like windmills these watermills are for the greater part superseded by steam power ; the locality, &c., must determine which can be used with most advantage. WINDMILLS. These picturesque objects are buildings containing machinery, to be driven by the wind, for grinding corn, sawing wood, and any other purpose that may be required. They consist of a basement, generally of stone or brick, and a superstructure surmoimted by a sort of dome capable of being tiuned round. From this dome projects the shaft of a wheel, and on this is fastened four fans or sails made of long bars of wood crossed by shorter ones ; these being covered with canvass, form a surface to catch the wind. These sails are placed obliquely to the front of the cross, so that when the wind blows upon them right in front, they are at an angle with it, they are therefore turned round ; for the wind which pushes them from the front, as they are u 242 APPAHATrS A>'D ATACHiyERT. oblique, tends also to push them on one side : when once in motion, being heavy, thev form a sort of fly-wheel to the machinery. The dome has several small wheels attached to its lower border, to act as friction rollers and cause it to be easily tui'ned round (which is often required), that the sails may be made to face the A\-ind in whatever direction it may blow ; this is sometimes done by ropes attached to the dome, but is more frequently effected by means of a small set of sails, shown in the cut, wliich are placed at riofht ancrles to the large set, so that when the wind acts on the large sails the small ones are not alfected ; but should the wind shift, these small ones begin to move, and they are connected with a toothed wheel acting upon a band which surromids the dome ; this is therefore caused to turn round whenever the small sails are turned, and as the dome turns, it brings with it the large sails until they are in the right position. These sails are generally fixed not quite upright, but inclined with their fronts looking a Httle upwards, which is foimd to be the best position to catch the wind. STPHOXS. Syphons are bent tubes for di'a'n-ing off liquids from cisterns, butts, &c., where there is no tap, and where it would be inconvenient to make any second opening. Fig. 1 gives the outline of the most usual form of syphon ; these are only used for liquids that may be drawn into the mouth APPAEATUS A>'D MACHiyEEY, 213 without injury, such as spirits from casks. Tlie mode of using the syphon is this — the bottom of the longest leg a is stopped with the palm of the hand, the tap is then turned on and the mouth applied to the small tube c, the air is then drawn out by sucking; the liquid rises and fills both legs of the instrimient, the tap is turned ofl", and the syphon is full. Now as the leg a is longer than the leg b, the fluid in it weighs more than that in h, and sinking down draws the fluid in b up, and so on till all is dra\\Ti from the cask. S\-phons are generally made of copper, but gutta-percha would answer exceedingly well. Fig. 2 represents a contrivance for dra\ving oft" acids, &c., which would injure the mouth; the ball prevents the acid rising into it, as the mouth is removed directly it begins to fill, which as the instrument is of glass, can easily be seen. STOP-COCKS OE TAPS. Taps are used for the purpose of letting oflT or stopping at pleasure the flow of liquids from vessels or through pipes. The forms of stop-cocks are very various, but the form shown at fig. 1 is by far the most general ; it consists of a short cur\ed tube, ha\'ing an upright cylinder in the centre in which a plug with a handle turns ; tliis plug is perforated in the direction of the length of the handle, so that when this is turned crosswise the communication is E 2 244 APPAEATUS AND MACHINERY. shut off (figs. 2, 3, and 4). The " nose " or end of the tap is sometimes prolonged into a spout, for filling bottles, &c., as in fig. 5. FIG. 7. The safety tap difters somewhat from the ordinary tap, a FIG. 9. section is seen in figs. G and 7 ; the plug is hollow and forms APPARATUS AND MACIIINEKT. 245 the nose or spout itself, this plug is only perforated on one side, so that it has to be turned round half-way instead of quarter-way as in the common tap. The upper part of the cylinder has an opening (of different shapes) leadinm- to the top of tlie plug, &c., a key being made to fit it (fig. 9). The American Avooden taps (fig. 8), are just like it, but have the handle united instead of a key. FIG. 10 FIG. 11. The four-Avay tap is a clever contrivance for uniting four passages in alternate pairs ; figs. 10 and 11 indicate the ditt'erent positions of the plug. This kind of tap was formerly an important part of the steam-engine, and allowed the steam alternately to enter above and below the piston. FILTEES. Filters are contrivances for separating substances from liquids which are not dissolved in them ; but in the most common acceptation of the t^'rm, filters are vessels used for separating the impurities from water. Filters on the ver}- large scale required by the water companies consist of sand or gravel so contrived that the water shall drain through them. This, indeed, is the natural way in which w(>ll or spring water is filtered; for the rain falling on the surfiice of the earth sinks do\\-n through such substances as gravel and sand, and lies in beds at the bottom, when it meets with stone or clay, through which it cannot sink (see 246 APPAEATrS A>'D MACni>'EET. " Artesian "Wells "). This water when drawn up is in most cases very bright, as it has been strained through the sand or gravel in passing downwards. The best substance through which to filter water for household use is sponge pressed together with some force, and this is the usual plan adopted in all the earthenware filtering vessels sold ; but there is usually a layer of sand or some other substance placed below, which is useless or worse, as it often becomes foul and taints the water. K the water has a bad odour, a few pieces of newly-burned charcoal placed in it above the sponge will purify it (see " Charcoal "). Filters for other purposes, and for any small quantity of liquid, may be made by cutting a piece of white blotting paper round, and then folding it into quarters and partially opening it (fig. 1) ; this if put into a fiuinel forms a convenient filter for any ^ J^ ii _y-''jv^ ,,'-'' '•-■-—■ V^ substance to be brightened, as water, vinegar, or wine. A particular kind of porous sandstone used to be hollowed out and used as a filter, but these filtering-stones are now but seldom used, except in the case of self-filtering cisterns, which are made by enclosing the inner opening for the tap in slabs of porous stone, so as to form a box within the cistern (fig. 2) ; by this contrivance, when the tap is turned, only that water escapes which has been filtered. It is necessary to have an air-tube to let the air in. as the filtered water runs out, and to let the air out as the water filters in from the cistern. Even in these cisterns a box of slate or other substance having several holes with sponges pressed into them would answer much better, as these coxild be APPARATUS AXD MACHIXEKY. 217 removed from time to time, -waslied, and returned. Filters, of course, cau only separate mechanical impurities, such as dust, insects, &c., for if sugar or salt were put into the Avater, all the filtering that could be used would not separate them when dissolved, and thus it is that well and spring water, although perfectly bright, are still very impure, con- taining much lime and carbonic acid dissolved in them, together with other matters, as iron, &c., which are not separable by filtration ; if it be desirable to separate them, distillation must be had recourse to (see "Distillation"). Some of these, however, as lime, may be separated by boiling the water for some time, which causes the Lime to fall down in the form of chalk, and adhere to the bottom of the vessel — hence the " fur," as it is called, in kettles. "Water con- taining lime, although quite "hard" and unfit for washing purposes, is made sufficiently " soft " for use by bodiug. Presses are contrivances for compressing or squeezing together substances that may require to be so treated, as in the case of extractmg the oil from seeds, &c. The earliest presses were simply heavy stones or pieces of metal, put on one after the other; but the gi'eat inconvenience and loss of time incurred in putting on and taking off these, soon led to the screw and lever, which form the usual screw press. The screw is fixed at one end in a socket and is turned romul by a long bar of iron or wood, and as the " worm " works in a corresponding hollow screw which is fLxed, it ascends or descends slowly but with gi'eat power. But by far the most powerful contrivance of this kind is the " hydraulic " press ; this machine is not only used as a press, but also to raise great weights, aud for many othej' purposes. The hydraulic press consists of a strong iron cylinder having a solid piston exactly fitting to it, this piston is raised by forcing water under it by means of a pump ; the principle depends upon the peculiar property which water and every other fluid has, of exerting, when confined in a given space, an equal pressure upon every part of that space ; thus if one pound pressure be 248 APPABATrS AXD MACIIIXEET. made upon one square inch, the water will press with one pound power upon every square inch of siu'face that it comes into contact with ; for example, suppose a cylinder, the piston of which is one foot measurement on the face — this foot contains Hi square inches — and from the bottom of the cylinder a tube should be made to rise a few feet above the piston, and that this tube should have an area of one inch ; then one pound weight of water poured in at the top of this tube woidd raise 144 poimds weight placed on the piston, for these 144 pounds would press but one pound on each inch, and the pound of water would have the whole of its weight on the one inch of the tube, they woidd therefore balance each other. But instead of pouring in the water, let a piston be fitted to the tube : a man with his hand can easily exert 100 pounds pressiu-e on this, and the result would be that he would raise 14.400 pounds or nearly six-and-a-half tons, and if to this small piston a handle and valves be fixed so as to make a pump of it he can easily pump in water at a pressure of two or three hundred pounds to the square inch ; and if instead of the large piston containing one foot area it has three or four feet, then the weight raised woidd be very great ; indeed there is no limit to the power of this instrument but the strength of the material used. It must however be observed that when the piston descends, say six inches, it does not raise the six-and-a-half tons six inches, but only a hundred-and-forty-foiu'th part of that distance, so that the piston would have to be raised and depressed six inches 144 times in order to raise the six-and-a-half tons six inches. But this is such a saving and concen- tration of labour that the application of the hydraulic press is becoming more in demand every day. STILLS. These are vessels of difltrent kinds used in distilling, that is, when any volatile product has to be converted into vapour and afterwards condensed, for the purpose of separating it from various matters not otherwise separable. One of the oldest forms of still is that even vet used in APPARATUS A>'D MACHIXEET. 249 most chemical operatious. called the "retort " (fig. 1). It is l)lo\\Ti out of glass iu one piece, is easily made of all sizes, not exceeding a few gallons ; it is chiefly used for dist illin g small quantities of fluids, and those which act on metals, as the acids. For some purposes, chiefly those requiring a very high temperature, earthenware retorts are used, and in other cases retorts made of platinum; the retort is often "tubulated," a name given to those with an orifice in the upper part ha\-ing a stopper fitted to it, this opening is useful to introduce any substance while the body of the PIG. 2. retort is already partly filled with its contents, or to add more of anything from time to time as it distils over. An indispensable adjunct to the retort is a "receiver" for condensing the liquid distilled; this is generally of a 2o0 APPAEATL'S XSD MACHI>'EET. globular form, with an opening to receive the spout of the retort, which is also frequently " tubulated " that it may be attached by a bent tube to a second or thii'd receiver. The receiver is to be kept cool, and this is generally done by a stream of cold water being poured on it, or a cloth dipped in cold water being spread over it, &c. The stills properly so called, such as are used in the manufacture of large quantities of liquids, as, for example, in the distillation of spirit, are generally made of copper tinned inside to prevent the formation of verdigris, and consist of a body, a head, and a condenser, the common form of which is seen at fig. 2. The condenser consists of a long tube coiled up into a spiral and placed in a large tub of water, ha\'ing a supply tube to let in cold water at the bottom, and one for the exit of the hot water at the top, for hot water being lighter than cold, rises up to the top of the tub. A very APPARATUS AXD 3IACHl>'EfiV. 251 good fot-m for a small portable condenser may be seen at fig. 3, in whicb a constant current of cold water is made to pass through the outer tube, and so keep the inner one cold. A distilling apparatus for experiments in chemistry can easily be made with flasks and bent glass tubes, fig. -i, or even by means of pieces of tube alone as in fig. 5, one being bent and the other straight ; the tubes and flasks can be united by means of corks perforated by a round or key- hole file. Empty oil-flasks serve well for this purpose, they can readily be cleansed by putting a little oil of vitriol into them, shaking it well about, and then washing them out with clean water. BLOWPIPES. Blowpipes may be considered as miniature blast-furnaces. They are little instruments used to force — by means of air blown from the mouth — the flame of a lamp or candle into a jet of flame so fierce that the very highest heat can be produced by it. Various forms of blowpipes are shown in the figures ; the common blowpipe, used by gas-fitters, r tinmen, &c., is shown at a ; better blowpipes have generally some reservoir to contain the condensed breath and so prevent it issuing into the jet ; the bulb sho-mi at b is for this purpose and also the conical part of c. Very good and cheap blowpipes may be made by bending a piece of glass 252 APPABATrS AND MACHiyEET. tube into the form sho-mi at d, adding a perforated cork and a small piece of bent glass tube fixed as in the figure. The end of the small tube, intended to produce the jet, should be held in the flame of a lamp or gas till it is red hot and turned roiuid all the while : in this way the hole will gradually become smaller as the melted sides collapse, forming a neat round hole about the size to admit a fine needle ; -vs-ith this blo^^-pipe a very great heat can be produced, and it can be easily repaired. The oxy-hydrogen blowpipe is a contrivance for forcing a jet of oxygen and hydrogen gases — mixed together in the proportions in which they form water — through a small orifice and setting fire to it ; this produces the very highest heat. Almost any svibstance can be fused by it, but the experiment shoidd not be made imless with a proper apparatus, as the flame will be sure to run do\vn the tube and explode the mixed gases with dangerous violence. A common flame is merely a cone of vapour burning on the surface where it comes into contact with the air. and therefore gives out but little heat, but when air is forced into it, a small blue cone of solid flame is projected, which gives off more heat than the hollow cone. THEEMOMETEES. Tlie thermometer is an instrument for determining the temperature of the air or any other fluid into which it may be introduced. The thermometers in general use contain mercury, but some contain colored spirit ; yet, as mercury is most generally used, it will be only necessary to say of spirit thermometers, that they act on the same principle. A thermometer consists of a glass ball having a long thin hollow tube rising out of it and attached to a graduated scale — the bore or hollow of the tube is very small, scarcely sufficient to admit a piece of sewing cotton. The ball or bulb and part of the stalk are filled with mercury by holding a lamp to the ball till the air is nearly all expelled by its expansion — for heat expands air very greatly — and putting the end of the stalk into a vessel of the fluid. ^Iien the lamp is removed the air in the bulb cools and therefore con- APPABATUS A>*D MACIITXEKY. 2.33 * tracts, by which means the mercnrj is forced up the fine tube, very nearly filling the bulb. The bulb is then held downwards and the mercury so heated that it expands, as did the air. till it fills the whole of the bulb and stalk up to the very top ; the top is then melted with the blow-pipe (see '' Blowpipes "), and the glass, running together, closes up the bore at the end. As the mercury cools it contracts, and consequently, occup\-ing less space, falls dowTi in the stalk pretty close to the bulb, the space above it is therefore empty, and forms a " vacuum." Xow, therefore, we have an instrument, consisting of a bulb and stalk half-filled with mercury (fig. 1). Upon any amount of heat being applied to the bulb, the mercury in it expands, and rises in the stalk in proportion to the amount of heat applied, or shrinks and sinks down again as it cools. The next thing to be done is to form a " scale " by which the height of the mercury in the stalk may indicate some known or recognised temperature. There are three scales in use, '' Fahrenheit's," " Eeaumur's," and the "centigrade." The scale universally used in England is Fahrenheit's, although both this and Eeaumur's are sometimes marked on the same thermometer (fig. 2). Fahrenheit's scale is formed thus : — The bulb of the thermometer is placed in j,j^ ,, boiling water, and the height to which the mercury rises is marked by a scratch on the stalk ; it is then put into snow or ice in the act of melting, and another scratch is made where the mercury has descended to. The space between these two marks is divided into ISO equal parts called degrees, and these divisions are carried upwards to nearly the end of the 254 APPAEATUS AXD MACHINEET. stalk and do^vniwards to near the bulb ; tbe upper scratcb, indicating the heat of boiling water, is marked 212, and the lower one, which marks the freezing point of water, being 180 divisions lower, will be 32 ; and of course, 32 degrees lower will be 0, and is called " zero." On the ?cale of Eeaumui''s thermometer the zero or point marked 0, is at the freezing point of water, and the boiling point is marked 80 (fig. 2). The centigrade diflers from Eeaumur's only in having the space between the boiling and freezing point of water divided into 100 parts instead of 80. AVhat are called " register thermometers " have two bulbs, stalks, and scales, on the same instrument (fig. 3) ; one bulb is FIG. 3. filled with mercury, and the other with colored spirit. In each stalk a piece of enamel, about half-an-inch long and fitting the cavity, is introduced ; the one in the mercury is to register the highest, and that in the spirit to register the lowest degree of heat. They act in the following manner : — The spirit, being very liquid or thin m its nature, wets the enamel and passes by it when it rises in the stalk, so that the elevation of temperature does not afiect its position, but when the spirit sinks do-wu it drags the enamel with it, thus registering the lowest temperature, so that the distance the enamel is found doAMi the stalk indicates how low the spirit may have descended in any particular time, say a night. With respect to the mercury, it is not of a nature to adhere to the enamel, and therefore instead of passing it pushes it up in the stalk as it rises, but on descending leaves it behind, the height at which the enamel is found up the stalk indicating the highest point to Avhich the mercmy had risen, and consequently the highest temperature. To adjust the instrument, a slight tap or shake will make the index APPARATUS A^'D MACIIINEKT. 255 in the spirit tube fall to the surface of the spirit, where it is held by the adhesive quality of the liquid, and by the same process that in the mercurial stalk will fall to the surface of the mercury, but will not penetrate it, owing to its great density. BAROMETERS. The barometer is designed to indicate the weight or pressure of the air on any surface, at any particular time or place ; for the air, although invisible, is still of considerable weight, as there are many miles of it pressing from above do^vnwards on all parts of e\'erything upon the earth, and the barometer is for the purpose of ascertaining how much this pressure amounts to. It is formed as FIG. 3. follows : a piece of glass tubing, about three feet long, is tirst closed at one end, then turned up at the other and expanded (fig. 1); when this tube is filled with mercury and held with the bidb downwards, the mercui'y sinks in 256 APPAEAXrS A>'D MACni>TET. the stalk to a certain height (say twenty-nine inches), and that height shows the weight or pressure of the air. The reason of this will be understood by supposing a piece of straight glass tubing, three feet long, to be closed at one end and then filled with mercury ; if the finger be placed on the end not closed, and that end tiirned downwards and put into a basin of mercury (fig. 2) before the finger is withdrawn, the fluid, if the air exerted no pressure, would all sink down from the inside of the tube into that in the basin, leaving a " vacuum " or empty space in the hollow of the tube, but it is evident if the air exerted any pressure on the surface of the merciu-y in the basin, this pressure woidd force the mercury up the tube (for there is no opposing pressure in an empty space), and that the mercury would rise higher and higher the greater the the pressure. "Well, then, the air really exerts this pressiu-e, and to such an extent as to raise the mercury somewhere about thirty' inches in height, and the pressure necessary to do this is found by calculation to be about fifteen pounds upon every square inch of surface. The barometer tube is divided into a scale of inches and fractions of inches. "What are called weather glasses, are barometers having the lower part brought up by a curve, and a small weight resting on the mercury in it, which being attached to a corresponding weight by means of a cord rimning over a little wheel or pulley fijsed to hands moving round a sort of dial, turns them as the mercury rises or sinks (fig. 3), for as the mercury falls in the stalk it must of course rise in the short stalk of the curve ; the hands by these means are turned round, and the rise or fall of the fluid vriil cause them to point to "fair," "rain," &c., as the case maybe, for these names are marked where a corresponding change of the weather may so influence the weight of the air, as to raise or depress the mercury', and so bring the hands in a position to point to them. pzynrLUMS. Any weight attached to a rod or wire so that it can swing freely may be called a "pendulum." But for the APPARATUS AXD MACHIXEEY, 257 purpose of time-keeping, a much more accurate instrument is required; the rate of vibration or oscillation of the pendulum, does not de- pend upon the weight of the ball or " bob " at the lower end, but upon the distance of this from the point at which the upper end turns, nor does the rate of oscillation depend upon the distance through which the weight traverses, for ever}' pendulum will vibrate at tlie exact rate (with certain restrictions) at which it is set otf, imtil it ceases, although the distance through which it traverses, decreases at every vibration ; these facts are taken advantage of ia adapting the pendulum to the purposes of regu- lating the time a clock shall keep — the longer thef pendulum the slower the vibrations. Now, as everything in natxxre is expanded by heat and contracted by cold, so a pendulum is constantly var\-ing ia length by ever}- change of tempera- tiu-e, and, as a consequence, the rate of the clock to which it is attached vriR also vary. Pen- dulums which have an arrangement to ob\iate this variation, are called "compensating" pen- dulums ; the best in use are of two kinds, one called (from its appearance) the " gridiron," the other the " mercurial," this last is the most accurate, and is used in nearly all good astro- nomical clocks. The gridiron pendulum is made of iron and brass, or zinc, and is con- structed as shown in tig. 1 ; the rod and outer frame, a, is made of iron, the two rods inside this of zinc or brass, B B. The principle of the instrument is this — brass or zinc contract and expand much more than iron does, and the short bars of these metals will expand or contract as much as the long bar of iron forming the rod of the penduliun, so that as this expands and lets the ■■' bob " down, the short bars expand and draw it upwards FIG. 1. FIG. 2. 258 APPABATrS A>TD MACHrSTBT. SO that it keeps its place at any temperature ; tliis requires very accurate adjustment. The mercurial pendulum is shown at fig. 2 ; it is on the same principle, but is easier to regulate, and more manageable, the vessel in the centre being partly filled with mercury, and forming the weight itself, and "thus as the mercury expands upwards it com- pensates for the elongation of the rod, the same as ia the gridiron pendulum. The nearer any pendulum is to the centre of the earth the more quickly does it Wbrate ; this has been used by scientific men, to determine by the difference of rate in one placed on a hill, and another at the bottom of a deep mine, the amount of matter which constitutes our globe ; indeed by these trials the world may fairly be said to have been weighed ! PLOrGHS. Ploughs are instruments used to perform more rapidly what may be effected by the spade, namely, the cutting-up and tiu*nuig-oyer the surface of the ground so as to destroy all grass and weeds growing in it, loosen, so as to expose it to the influence of the air, and render it fit to receive the seed. The plough has been in use from the very earliest ages, and has been but little altered for many centuries : it is drawn by horses attached to the chaia a at the end of the "beam," and guided by a man holding the '"stilts" or handles b b, the coulter, c, cuts a perpendicular slice in the APPAEATUS AXD MACHI^TET. 259 ground, and the "share" or "slade," n, following, cuts horizontally, so as to separate a long piece of eaith which the breast or mould-board e, placed obliquely, turns over on one side ; the plough retiu*ning at regular distances, successive cuttings are thus laid side by side, forming narrow ridges ; f is an additional coulter called the " skim- coulter," for removing the surface of the earth, and is onlv occasionally used. Tliere are a great many kinds of ploughs, each suitable to the kind of soil to be ploughed, whether light and dry or heavy and moist. HAEEOWS. Tliese instrvmients are used to stir up, pulverise, and mix together the earth, also to tear up any roots that may be left after ploughing, and to cover up the seed after so\nng. The cut represents the usual form of harrow, having a number of iron spikes or teeth attached to frames of wliich two or more are united together by chains and attached t(> a bar, that the horses may drag them over the surface of the soil. Bush-harrows consist of a bundle of brush-wood held together by a pair of frames, and drawn over the soil when it is ver}- dry and light ; they are used chiefly to cover up the seed after ** drilling." s 2 260 APPAEATrS AXD MACHINEBT. EOLLERS. In clay and otlier lieavy soils, it is necessarj^ after ploughing to break up the large pieces by means of rollers, and in light soils to press it together ; for these ptu-poses rollers are used, either with smooth or undulated surfaces, as in the figure ; these last form furrows into which the seed falls, causing it to come up in rows. Eollers of a lighter kind are used after mowing to level the surface. MOWING MACHIKES. Mowing is an operation gene- rally performed by manual labour, by means of that well-kno-«-n in- strument, the scythe (fig. 1), which is a long, flat, curved blade of steel attached to a handle ha^nng a peculiar bend, and with two short pieces of wood attached, by which the mower swings it roimd with a measui'ed sweep, cutting off" the grass almost close to the ground, walking gradually forward as he mows ; but of late years machines of various kinds have been invented and used for this pui*- pose. Fig. 2 represents one Avhich not only mows, but at the same time rolls the grass, so as to make it smooth and level. It consists of a heavy iron roller turnuig a large wheel, which, being united to a small one, cavises it to revolve very rapidly. In connection with the small wheel is a series of four spiral knives wound round a APPAEATUS AND MACIIIXERT. 2G1 cylinder, which cut oft" the grass close to tlie ground, throwing it up into a box placed to receive it. There are several varieties, hut this is the kind made by Drav & Co., London, for mowing short grass, as in gardens and lawns. Those used for cutting long grass for hav, are exactly similar to the reaping machines. THRASHING- MACHINES. Tlie operation of thrashing, performed for ages by means of the •' flail " — two sticks tied together and -ft-ielded by the hands, inflicting heavy blows on the bundle of corn spread on the thrashing-floor, so as to separate the grains from the ear — is now being rapidly superseded by the thrashing-machine. It is a sort of box liaving a cylinder inside with an iron wheel at each end united by bars of iron ; this wheel revolves by steam, causing the bars to lall upon the corn with a gliding motion, thrashing out the grain, which falls through and is received below. EEAPIXG ilACHlXE. EEAPiya irACHI>'ES. Macliines have lately been produced to effect more rapidly, what has hitherto been done by hand, "vs-ith the sickle, namely, the reaping of corn. These machines are of various kinds, but the one that seems most perfect has been patented by Messrs. Dray & Co. ; it consists of a heavy ■wooden frame dra^vn by a horse, and having wheels attached, which on turning round set in motion a line of spear-headed knives; these knives are made sharp at each side, to cut both ways. The motion communicated to them is very rapid, and from side to side, so as to cause the knives to pass through long narrow openings made to fit them in a series of iron points which are placed one between each knife. This action causes the APPARATUS AXD MACHIXERT. 2G3 point and knife to act like the blades of a pair of scissors, only that the points are fixed and the blades move through them, cutting off the corn at any distance from the ground that may be required ; at the side furthest from the horse is a point of iron, having two diverging pieces prolonged from it, and which pierces the corn and separates the portion to be cut ii'om what is to be cut at the next return of the machine ; for it is drawn up and do\^-n, cutting at each time a belt about four or five feet -n-ide ; when cut, the corn falls on a platform balanced on its centre, and capable of being turned so as to incline forwards or backwards. A man sits on the machine with a rake, and as the platform fills ^\•ith cut corn, he pushes it with the rake, tilting the platform back and delivering the com behind, where women attend to bind it up. These machines ciui reap ten or eleven acres in a day. DHILLS. The drill is used when it is desirable to sow seed in rows at intervals from each other, so as to give room for the plants to grow, to free them from weeds and admit air, light, and moisture ; it is a machine which contains the seed for sowing, and at the same time makes a series of furrows to receive it. There are a great many varieties 2Gi APPAEAXrS AXD MACHINERY. of drills, but they act upon the same principle, namely, that of a cyliuder, taking up and pouring small portions of the seed into funnels so arranged that they shall follow a set of small coulters forming furrows in the ground, into which the seed falls ; the drill is generally foUoAved by a bush-harrow which covers up the seed. Some drills have two compartments, one for containing manure, the other for seed ; the manure must be dry and pulverised, such as ground bones, ashes, &c., which arrangement allows the seed and manure to be both drilled together, so that the manure shall only be applied where it is wanted. The cut represents this machine ; A A are portions of the cylinders which are turned round by toothed wheels attached to the ordinary wheels of the machine, and which can be put in or out of gear at any time, so as to stop the action of the drill ; B B represent the funnels into which the seed is poured, and c c the coulters which cut the furrows for the seed. These coulters are pressed into the ground by means of iron weights attached to the ends of levers joined to them, and which can be regulated by small chains. EXGI^^EERING WORKS. KAILWAYS. Tlie fjreat aclvantac;e of railways over ordinary roads is the diminished friction, which is produced by the wheels passin'gi>t:eei>-g woees. As it i5 necessary that trains should at certain places be "shunted" or shitted from one line of rails to another, particuki'ly at stations where a great many tracks run side by side, and cross each other to branch off to different l^arts, there ai'e arrangements called " points," shifted bv a lever or " switch," so that they shall direct the course of the train, and cause it to leave the former track and enter upon a new one ; this arrangement may be seen at fig. 5, where the points are in the position to direct tlie engine coming in the direction of the arrow on to the ciu-ved line a, and the dotted lines indicate the position iuto which they would be shifted, if necessaiy for the train to go straight on to the line b ; this action is effected by moving a lever which shifts the two bars a few inches either way. "Wlien an engine ^i&- ^- or carriage has to be ttmied on to a track at right angles to the one on which it rests, or where there is not room for "shunting," an apparatus called a '• turn-table " is used, which is shown at figs. 6 and 7 ; it is a round platform of iron tiu^ning on its centime, and sup- ported by friction rollers at the edge, ha^^Jlg on its surface raised rails in two or more directions, bo that it may be turned round half or quarter distance, according to the ZNGIJrKEnLN'G AVOEKS. 269 position required. The engines and carriages used to run on railways are of various constructions, but to a certain extent agree in their chief particulars; the wheels are fixed to their axles, so that each pair and the axle which joins them may be considered as one piece. The axle projects a little way beyond the wheel, and on this part pari; it supports the engine or carriage, which is wider than the distance from one wheel to its feDow. They are therefore entirely underneath. They are of iron, made by machinery and have a projecting edge on the inside of the '"tire" of each, which is called the "flange" (see fig. &) ; this flange does not run on the rail but within it. to prevent the wheels from slipping off". These flanges, wlieu the pair of wheels and axle are united, exactly fit in ^is- *■ between the rails, so as to touch the inside of each and form a sort of guide. Each carriage has Irwo pairs (except in a few cases, where three pairs are used), the engines have usually three, and some- times four pairs. The carriages rest upon powertul springs, and are moreover furnished with springs to diminish the concussion of one carriage against another ; these last are acted on by a sort of piston-rod. one of which is placed at each comer of the carriage, and are called "biiffers" 270 ENGINEEBING WOEKS. (figs. 9 and 10) ; tliey all coincide with each other, and form a set of springs all along the train, which greatly reduces the shock which would otherwise be felt when it is stopped. Another set of springs is connected with the binding screws which unite each carriage, and these prevent the sudden jerk which would residt from the starting off of a train quite inelastic in its length. riG. 9. PIG. 10. Tlie engines used are of that class called high-pressure or non-condensing, and there are two cylinders and pistons, which have a stroke of about eighteen inches. The boiler is so contrived that a large quantity of steam shall be rapidly produced ; for this purpose tubes of brass ai'e made to pass side by side from the fireplace through the boiler, and through these tubes the flame and hot air must go before reaching the fimnel, gi'V'ing out in its course a great amount of heat to the water and converting it rapidly into steam. The steam from each cylinder passes at each stroke of the piston into the funnel, assisting to forai a draught Avhich draws the flame from the fire through the tiibes and increases the fierceness of the combustion. The necessity for two cylinders and pistons is owing to the impossibility of having a fly-wheel, and as the driving wheels of the engine have to be turned at an equal rate, the axle has two cranks so placed that the greatest power of one piston is exerted where the other exerts the least (see " Steam-engine). As the trains when ,c;oing at a considerable speed cannot be suddenly stopped, it is necessary to have signals placed in certain conspicuous positions, that the engine driver FIG. 1:;. may begin to stop the train (when necessary) in time ; tliis he effect by what is called a "break," a contrivance br Tivliicli tvro pieces of wood are made (by tnmins: a screw) to grasp firmly each of a pair of wheels, and so prevent them turning round, this produces so much friction against the trams that (after the steam is turned ofi') the onward motion of the train is soon stopped. The signals are of three kinds generally, a red flag to indicate danger, a green one to caution, and a white one to show that the way is clear ; these are (on most occasions) held by a man and waved to and fro to attract attention, but there are however a great many occasions for fijsed signals, as at stations and bends in the line where the engine driver can only see a short distance ahead; these fixed signals consist of tall posts placed where they can be seen at a considerable distance. These posts have an arrangement at the top con- sisting of a lamp with a '■ bull's-eye " or lens at each side pointing up and down the line, and a pair of arms capable of being let dowTi into the post, raised at right angles A^-ith it, or into a position midway between the post and a right angle (as shown in figs. 11 and 12). One side of each arm is painted red, the other whit€, one arm sending for a signal up the line and the other down ; attached to the joint of each arm, close to the post, are two iron frames each EN'CaXEERIXG WORKS. 273 holding a piece of colored glass, one red the other green, and so arranged that when the arm is at right angles to the post, the red glass is before the lamp and when the arm is let half way down the green glass comes in front of the lamp (fig 13), thus the same action senes both for day and night signals. AVhen the arm showing the red side projects in a horizontal direction, it indicates (in the day) " danger," and so does the red light at night ; when the arm is let down half way, it shows that caution is required, and the green glass then before the lamp shows the same signal at night ; when the arm is let quite do'wn out of sight, it shows safety, and so does the white light of the lamp thvis freed from both screens of colored glass. Each engine is proWded vrith a whistle (fig. 14) blown by steam turned on from the boiler, which is used as a signal at any particular time, especially in tunnels or when there is a fog ; there is also an arrangement by which each engine presses on a lever at the side of the tram as it passes, and causes a bell to ring at the station, to announce its approach, when about a quarter of a mile ort". In some cases, as in foggy weather, when the usual signals cannot be seen, a packet of fulminating powder is placed on the rail, and this being exploded by the wheel of the engine as it passes over it, gives notice of its approach, Ac. There are other signals, but these are the chief. ELECTBIC TELEGE.VPUS. The power of transmitting messages to any distance or place to which a wire can be carried, and in a space of time too small to be reckoned, is without doubt one of the most wonderful inventions ever carried out by men's hands. Although the signals are carried from place to place with a rapidity almost incredible, yet the electric fluid travels at a certain, although marsellously rapid rate. It is thought that light and the electric fluid both travel at the same rate. 'ij*A^\*\i^ namely, 192,000 miles in a second, and if so, a message might be sent round tlie world (were it possible to carry on a wire) thrice in that small space of time. The construction of the electric telegraph is pretty much the same everywhere, only that modifications of the same agent are used in different countries, and different signals formed ; but whether this agent or influence is obtained from magnetic or galvanic sources, the result is exactly the same. Wlien a pair of metallic plates are immersed in a fluid which acts chemically more rapidly on the one than the other, and a vdre connects the upper parts of these plates, this wonderful agency is set in motion, and circulates from the one plate to the other (fig. 1). This arrangement may be best shown by using one plate of zinc and the other of copper, and a dilute solution of sulphuric acid for the liquid; this, however, produces by ENGIXEERIXG WOBKS. i'or too little of the agent to be used on a telegraphic line, there are therefore combinations of such pairs of plates so arranged that the power of one pair shall be added to the next in such a ■way that at the end of the series (called a "battery") there shall be a great increase of the power accumulated — this arrangement is sho\vn in fig. 2. Xow (if the power be sufficient) it does not signitV what length of ^^■ire there may be between the two ends of this arrangement or " batters." whether the ends be connected by a few feet of wire, or as many hundred miles — the electricity passes instantaneously from one end to the other ; and furthermore, it has been found in practice, that this electrical inilueuce can be transmitted through the earth in one direction if sent bv a wire in the other ; for / --mMf^?^ instance, if a wire from one end of the battery- be carried on from London to Liverpool ; instead of haviug another from Liverpool to London, to connect the two ends of the battery, it is found to answer the same purpose if the end Flu. 3. of the w ire at Liverpool be fastened to a plate of metal buried beneath the surface of the earth and the other cud T 2 276 EyGI>TEBI>'G WORKS. of the battery at London, fumislied -with a similar plate also buried. In this arrangement, the electricity' will pass beneath the surface of the earth from Liverpool to London, and through the wire from London to Liverpool, thus completing the circuit. The end from which the electricity passes is called the " positive electrode," that to which it returns the '•neo:ative electrode." Fig. 3 vriR show this arrangement. K a bar-magnet be suspended on a pivot so that it may turn freely, it will (as is well known) tiun with one end to the north, which is owing to a ciu'rent of natural electricity passing round the earth in the direction of east and west, the magnet crossing the current at a right angle ; and if a coil of wire coated with silk (to keep one part of the coil from another) be placed round, above and below the long axis of a bar of steel as shown at fig. 4, and a current of electricity passed through this wire, the steel becomes a magnet and will take a direction similar to the natviral magnet, more or less at right angles to this coil, as in fig. 5, according to the intensity of the current ; and the instant this electrical current is" stopped it will resume its former direction. This fact has been made use of to form the principal feature of all English telegraphs ; in the telegraph such a needle is mounted in an upright position, and instead of its tendency to turn to the north, a tendency to maintain ENGINEERIKG WORKS. 2t I the upright position is given to it by having one of the anus of the magnet a little heavier than the other ; such a magnet ha\'ing a coil of \\\vq surrounding it. "When the electric current passes through the coil, it will tiu-n out of the upright position to either one side or the other, according to the direction of the current, from its tendency to assume a position at an angle to the current (fig. 6) ; if the current be stopped even for an instant, then the needle or magnet will again assume its upright position. The pivot of this magnet is brought forward and has on its front part another needle, which being on the same pivot turns with it ; this is visible on the outside of the apparatus, and is looked at to ascertain the movement of the one within. There is also an arrangement called a "commutator," so contrived, that by moving a 'handle to the right or left, a connection shall be made with either end of the battery, and thereby cause the direction of the current and needle to be changed at pleasure ; also by monng the handle into an upright position the current shall be stopped ; and finally, by a third movement, a bell shall be rung. Xow, as has alreadv been explained, when the ciu-rent goes in one direction, the magnetic needle is deflected in tliat direction ; and when the current is reversed the position of the needle is also reversed, and when the current is cut off the needle Avill resume its perpendicular position. If two such needles and two such handles be at each station, when the handles at one station are moved, the needles at the other station will take on a similar movement ; and when the handles at that station are moved, the needles at the first station ■s\-ill be moved to correspond. This constitutes the svstem of communication kept up by the electric telegraphs in England ; but it remains to be shown how all the letters of the alphabet, the numerals, etc., can be represented by the movements of the two handles. These handles can be placed in eight positions (besides the upright one) by a single movement of each hand, as may be seen in fig. 7 ; and these eight signals if repeated, or made twice in rapid succession will make eight more, and by being repeated three times will constitute a third eight, making twenty-four ; finally, by 278 ENGINEERING WOEKS. a rapid motion right and left, they may be caused to signify a fourth eight, or thirty-two signals, which are found to be sufficient for every purpose, and by practice may be both produced and read off Avith facility. Before a message is about to be delivered the commutator is so placed as to ring a bell, which is done by the same arrangement as in a common alarm-clock, but the action is set in motion by a peculiar contrivance, which depends upon the property a bar of soft iron has of becoming magnetic when a ^3 \/ f\ wire is wound round it and a current of electricity passed through this wire ; this magnetic property exists only as long as the current passes, and stops the instant it is cut off. The catch of the alarm is disengaged by the movement of a bar of iron being drawn to the magnet while the current passes, and forced back again by a spring when it is stopped, thus setting in action the mechanism of the alarm, or in some cases there is a simple contrivance for causing a rapid flow and stoppage of the electricity, so that the bar is alternately attracted by the magnet and released by the spring, and this motion of the bar rings the bell as long as it is continued. The bell is always rung to give notice that a message is about to be sent, and at the station where the bell rings, the bell at the former station is rung in return, to show that they are prepared to receive the message ; the message is then spelt letter by letter, by moving the handles into the proper positions, and as the message is being sent, the eye is kept on the dials having EKGINEEEING -WORKS. 279 the needles whieli will eommuuicate any message in return from the station to which the message is being sent, such as "repeat," "not understood," &c., &c., for which certain single signs are made and recognised. The wires which convey the electricity from station to station, are made of galvanized iron (iron coated with zinc), and must be kept from all commniucation with the earth by some substance incapable of conducting it ; they are therefore stretched between wooden poles (fig. 8), and rest npon sockets or supports of glass or glazed earthenware, which are both substances incapable of conducting the electricity to the earth (fig. 9). In certain localities, as in towns, the wires are coated with gutta percha (another non-conductor), and laid side by side in a tube under ground ; this is also done in the longer tunnels. In the cables wliich conduct the electric power along the bottom of the sea as from Dover to Calais ; the wires are first coated with gutta percha, then bound with yarn soaked in tar, and finally coated with galvanized iron wires wound round spirally like the strands of a rope (fig. 10), the whole forming a cable which is coiled up in the hold of a vessel, and let out as the vessel crosses from one side to the other ; in this way the cable is deposited on the bed of the sea or channel, forming an electrical con- nection from country to country. These cables are made in one piece by machinery. That from Dover to Calais is 280 ENGINEEEING WOEKS. twenty-five miles long, contains four copper conducting wires, and weighs about 175 tons ; that from Dover to Ostenid contains six conducting wires, is seventy miles long, weighs nearly 500 tons, and cost about £30,000 ; its structure (the real size) is shown at fig. 10. The electric cable now constructed to be laid do-RTi between Ireland and America, is composed of seven small copper wires t\dsted into one, and surrounded by gutta percha ; this is then siirrounded by eighteen small wire- ropes, each composed of seven small wires twisted together, the whole being in its section not larger than a four- penny-piece : 2000 miles of this cable are now ready to be laid doA^oi. A plan was some time ago put in practice by which the correct time could be kept at various places by electric communication with the time at Greenwich ; a clock thus regulated, is situated at Charing Cross, and a ball placed at the top of the electric telegraph station there, is caused by the same means to fall exactly at one o'clock. A contrivance has of late been patented to work the electric telegraph by steam, and the following account of it is extracted from the " Times :" — " A series of gutta percha bands, about six inches wide and a quarter of an inch thick, are coiled on wheels on drums arranged for the purpose. These bands are studded down both sides with a single row of holes at short intervals apart. AVhen a message is to be sent the clerks wind off ELECTRIC TIME BALL, CUAKING CROSS. lliese bands, inserting in the holes small brass pins, which, ai'cording to their combinations in twos or threes (with bhink holes between), represent certain words or letters. In this manner the message is, as it were, "set up" in the bands with great rapidity, and if the number of bands employed is sufliciently large — say as numerous as the conijiositors employed in a large print iiig-ollice — messages equal in lengtli to five or six columns of this journal could be set up and ready for transmission in the course of a single hour. Of course this ojieration in no respect interferes with the telegraph wire itself, which contiiuii'S free for use until the bands of messages are actually beini^j despatched. The gutta percha bands when full are removed to the 282 EyGiyEEEI>"G -SVOEEiS. instrument-room, a most simple appliance preventing any derangement or falling out of the pins while being moved about. In the instrument-room the bands are connected with ordinary steam machinery, by which they are drawn in regular order Avith the utmost rapidity between the charged poles of an electrical machine in such a manner that, during the moment of each piu's passing, it forms electrical commimication between the instnmient and the telegraph, and a signal is transmitted to the other end of the -wire, where the spark perforates a paper and records the message. The only limit to the rapidity of the operation is the rate at which the bands can be drawn, since the electrical contact of each pin, even for the 200th part of a second, is more than sufficient to transmit a word or signal from London and register it in America. Of course, as the message is recorded (we will say in America) -sA-ith the same rapidity as that with which it is transmitted from London, a number of reading clerks ^ill be requisite in order to translate it. by dividing it into small portions, with almost as much facilitv as it has been sent." EOADS. Uoads. which were formerly of the utmost importance as the only means of communication between distant places, and on which an enormous amount of labour and capital have been expended, are now becoming rapidly subordinate to railways ; however this may be, it is quite clear that roads EXOrSEEBIXO ■WORKS. 2S3 can never be superseded by the latter. The numerous streets of great towns are so many short roads, and on some of them the amount of traffic is so very great, that the utmost skill of the engineer is required to resist the consequent wear and tear. The Eoman roads, which have been the means of civili- sation to the greater part of Europe, were constructed in a ver}- solid and durable manner, by lirst laying down a layer of rough stone set in cement, and upon this, stones eitlier squared or nicely fitted together and also cemented ; the whole formed a solid mass of masonry-, not unlike the wall of an old castle laid horizontally. Basalt (a volcanic product) was the stone used for this purpose, where it could be procured. These roads were generally raised above the surrounding ground, but excavations, bridges, and tunnels were made where these were found necessary to continue the road in a direct course. Eoads ore now generally made in a less careful manner, and the same observations as to course and levelling will apply to them, that are made on these subjects in the article " Eailways." only that less cutting and filling up are required, as the gradients on common roads are aDowable of much greater steepness than on railways ; one in twenty- five is however about the greatest declivity that should be made, although old roads exist with slopes much greater. The surface of a road should be slightly arched and a drain made on each side, that pools of water may not collect on its surface and soften it so that it will work into holes. Ordinary- roads are made by laving down a stratum of broken granite or other hard stone a few inches deep, each piece being of about half a pound weight, when this first layer is worked in by traflic. a second is laid, and so on till the surface has become quite firm and level, but in the streets of towns more care is required. In the suburbs of London, the usual plan is, to lay a deep stratum of rubbish, consisting of broken bricks, potterA' and oyster-shells (obtained from the dust-bins of London) nearly a foot in thickness, and on this, broken stone or shingle (consisting of pebble stones) is laid in repeated layers as it consolidates, 2si EyGI>T:ERIXG "WOBKS. but in the streets having more traffic the roadway is made by a foimdation of " concrete," consisting of coarse gravel and lime made iato a sort of paste, which sets into a hard cement ia a day or two ; on this foundation (which is care- fully smoothed on the surface) is laid a paving of squared granite blocks, placed carefully side by side either in lines at right angles to the road or else dia2:onaUy. When these are all laid do\vn and rammed to a perfectly even surface, a mixture of quick lime and sand is made into a thin paste with water, poiu-ed on and swept all over the surface with brooms, so as to fill up the inter- stices and cement the blocks of granite firmly together. In London the road- ways are always made arched, so that the centre is a few inches higher than the sides, and a gutter or drain is placed on either side between it and the pavements which run on each side, but in many to\vns in the country, and on the continent, the gutter is placed in the middle of the road and each side made to slope slightly towards it. BEIDGES. The earliest efforts of the civil engineer were in all probability directed to the construction of roads, but it would be evident that vmless they could be made to cross rivers and water-courses, they could continue but a short distance in any required direction. Bridges of some sort must therefore be constructed ; small brooks were doubtless bridged over with timber laid across them, and '"fords" or shallow parts of rivers taken advantage of when the stream was too A^dde to be spanned in this way. That these fords were once very numerous in England, is shown by the constant recui'rence of such names as Stratford, Brentford, &c., and indeed fords are now in use in many places where the stream is shallow, and the traffic too little to pay for constructiag a bridge. The next improvement in all pro- EN'OINEEBING AVORKS. 285 bability consisted in placing stones in the fords to enable passengers to step from one to the next, and cross the stream dry-footed, •which were called " stepping stones ;" but the earliest bridges properly so called, were pi'obably stones piled upon each other and united by beams of timber. The Chinese, Eomans, and several other nations were acquainted with the use and proper mode of constructing bridges, many centuries ago, when no such works had been attempted in England. The materials chiefly now in use for bridges are stone, brick, iron, and wood, and by far the greatest number, till Anthin the last half century, were constructed of stone, but iron seems to be rapidly taking its place, especially since the mode of constructing suspension bridcjes has been more perfected. There are several wavs of forming the foundation for the piers, or those parts on which the bridge rests. Old London bridge and many others of considerable size were based upon "piles," these piles consist of great pieces of timber pointed at one end and driven deep down into the bed of the river close together, so as to form a solid mass on the top of which the stones for the piers were laid ; these piles have been found scarcely altered after several centuries of immersion in the mud, but at the parts exposed to the action of the water they soon become decayed and eaten away by its inhabitants. For many bridges, when there is good foundation, the stone- work is laid at once on the bed of the river, but in order that this may be got at, a double ring of piles is driven close together aroimd the part where the pier is to be built ; these piles are of a Hat form, and the two rows inclose a space of about a foot between them, which space is filled with clay, well rammed in, and the water within the barrier pumped out, this forms what is called a " cofler-dam," and is an expensive proceeding. The bottom of the river thus exposed can be built upon in the usual way. Another way of forming a foundation lor piers consists in lowering lar<,'e wooden frames or boxes filled with concrete which hardens and forms a solid basis, these are called " cassons." Wooden bridges are now seldom made of any great size, but are very numerous in country places for crossing narrow streams, on 2S6 EXGIXEERING WORKS. account of their cheapness and the facility with which they can be constructed. Bridges of brick are not much used, but ''viaducts" of this material often occur in the lines of railways, and very handsome arches of brick-work are used to span streets in towns where railways pass. Iron girder bridges also, are frequently employed for this purpose ; they are made with girders of wrought or cast ii'on which generally pass in a straight line over the roadway from pier to pier. (Some of them are made of iron-plate rivetted together, while others are strong gii-ders of cast iron having small arches of brick-work built on them, running the length of the girders and restmg upon ridges in them, so as to iill up the space between each girder. THE BEiTAXXIA TCBULAE BfilDGE. Iron bridges are of almost every form and construction conceivable ; some are tubes of iron-plate, as the Britannia Bridge, rivetted together ; some of solid cast iron work as Southwark Bridge, others called suspension bridges are hung by rods of WTOught iron, from large chains suspended from pier to pier, as Hungerford Bridge. In many places bridges of boats are used ; the boats are moored' to the EKGINEEKING ■WOBKS. 2S7 river's-bed and have timber- work connecting them. Another kind, which can hardly lay claim to the name of bridge, called the " floating-bridge," is used for the conveyance of carts, horses, passengers, or merchandise, from one side of a river to the other. It consists of a sort of platform guided by chains laid do^^"n for the purpose, which pass over wheels or drums on the side of the bridge. The motive power necessary for turning these wheels, is supplied bv a steam-engine within the structure itself. TUXXELS. Tunnels are undergroimd passages made for the purpose of continuing roads, railways, or canals through hills or ele- vated parts of the ground. ' In slight elevations " cuttings " are generally made, and it becomes a question of expediency for the engineer as to which of the two shaU be chosen, as there \vi\\ be a much greater q\iantity of earth to remove from a deep cutting than from a tunnef ; in fact, the question is often at once determined by the demand for this material, for if it should so happen that the level of the road is such, that many or large embankments are required, the earth taken from the cuttings will be wanted to construct them. As a general rule, tunnels arc only made where a hill has to 2S8 EXGINEEEIXG ^OEES. be penetrated which, is too high to be cut through ; another object sought by tunnelling is to cause the road to pass beneath a canal, river, buildings, or roads, where the level of the road or railway is far below them. The Thames Tiumel is the most remarkable example of this kiad of work. Tunnels were constructed by the ancient Greeks and Eomans, chiefly for the purpose of forming aqueducts, and for draining lakes. A few years back, tunnels were not very frequently undertaken, those that were made being chiefly on the lines of canals, but they are now far more numerous, on accoimt of the great number of railways, on which they frequently occur. Before a tionnel is undertaken, the nature of the soil should be thoroughly examined by means of "borings," sunk down to the intended level, some soils being much less favourable than others for this purpose. Quick- sand, or sand percolated by water, is one of the greatest impediments to tuainelling, while rock (contrary to what would at first be thought) is one of the least, as in this case there is no occasion to line the tunnel with brickwork, which more than saves the extra expense of excavation, as that can be rapidly done by blasting, where it is too hard to dig, while in the former case the difficulty of draining ofl" the water, and the cost of brickwork of sufficient solidity to support such loose earth, often prevent the imdertaking. Tunnels of great length are sometimes begun at several diff'erent part§ by means of shafts sunk down to the required level, and each made to unite into one, but this depends upon where the earth is to be deposited ; on railways it is conmion that the " level " is so chosen that the earth from tiumels and cuttings is always wanted to fill up hollows in their immediate vicinity (see " Railways "), and when this is the case a series of " trucks " drawn by an engine on temporary tramways remove the earth from the tunnel as it progresses, to the next embankment, both works proceeding at the same time. AYhen a small portion of the timnel is excavated, the casing of brickwork is begun from the mouth of it, and continued a small piece at a time, following closely the excavation. The brickwork is generally begun at each side, EKGINEERIXG WORKS. 289 and carried up to the height at which the arch springs ;• an inverted arch is tlien constructed from one side to the other to form the floor, and " centreings "■ resting upon uprights are phiced, to '* turn " the arch upon. These centreings are only ahout two feet deep, and span the arch from side to side ; the men work with their backs to the part being excavated, and are able to reach across the narrow centreing to lay the bricks. AVhen completed all round, and the spaces between the brickwork of the arch and the surface of the excavation tilled up with earth, the centreing is shifted further in and a fresh ring of brickwork commenced, the excavation going on at the same time. In many tunnels, large perpendicular shafts are sunk doA\Ti for the purposes of ventilation and lighting. DRAI>'S. Drains are constructed for the purpose of carrying off from the surface of the groimd all superfluous fluid, whether it may arise from want of a proper exit for the rain, from springs rising in the ground to be drained, or from water coming from some higher level. Drains are made in towns to carry ofl" the rain from the surface, and all liquid refuse from the houses. When the surface of any portion of land has to be drained of its accumulated water, where the soil is of an impervious nature, like clay, it is usual to cut deep furrows from the higher to the DRAIX-PIPES AND TILE3. lower parts and fill these up with gravel stones or brush- wood ; the moisture which collects in these is made to flow 290 EXGIXEEEiyG "SV0EK3. into the lo'n-est part, and there form a pond, from ■which, it evaporates as fast as tlie drains supply it ; or if the quantity- be too great, a main drain or ditch carries it onwards to some stream or river. The furrows before being iilled up with any porous substance are often laid down with "drain-tiles;" tiles bent into the form of half a cylinder, and placed with two edges on a flat tile at the bottom of the drain, or pieces of tubing made of tile. The water finds its way readily into these through the crevices. In some cases, water can be kept from flowing over lands and forming marshes, by embankments. These are more especially useful in land lying below the level of rivers and lakes ; immense tracts are thus preserved in Holland. "^^Iien these embankments are very extensive, there is a constant filtration of the water through them ; drains are therefore constructed to collect it into certain spots, and mills erected to pump it over the banks. These are usually small wind- mills, working a large wooden screw in a cylindrical barrel, causing the water to rise up the cylinder into a trough, from which it is poured over the embankment ; these mills require little or no attention, and work at all times when the wind blows. AVhen water accumulates in valleys lying above the sea, deep cuttings or even tunnels may be necessary to carry oft' the water ; at Xeufchatel in Switzerland, very extensive tracts of land have been reclaimed, by boring a tunnel through the surrounding hills, and thus letting oft' the water from the lakes formed by the rain. Sometimes land may be drained by boring through the clay or other imper\-ious soil, dovm. to a porous stratum, such as sand or gravel. A knowledge of the structure of the whole district is necessary to determine whether this is likely to be of ser"\"ice or not. By boring deep pits in the drains cut in peat mosses, the weight of the mosses will cause the water to be squeezed out, which rising in these holes flows off by the drain, producing the same eftect as if it were cut to the depth of the pits. Drains are frequently made by means of narrow curved spades, but the draining plough eftects the purpose more rapidly, and is very generally used. ZyGIXEERIXO WORKS. 291 The drainage of London and other large towns consists of small drains from each house, made of earthenware tubes leading to a sewer of brickwork, running along each street and uniting with larger ones. The question of effectually drainins: London is a ver^' difficult one, schemes of various kinds being at this time propounded, which would cost several millions of pounds to put into practice ; at present all the sewage nins into the river Thames, and it is a matter of serious importance to obviate this, by carrying it off to some other place. AETESI.VX WELLS. The construction of artesian wells depends upon the fact that water, being at liberty to flow, will always sink to a level ; by which it is meant that the parts which are highest press upon those that are lower, and tend to raise them, the higher parts sinking in the same proportion that the lower parts are elevated; this continues until both are upon a level. Suppose a bent glass tube of the form of fig. 1, be partly tilled with water, the surfaces of FIG. 1. FIG. 2. the water in both arms of the tube will each be upon a level with the other; suppose now another such tube to have a small hole at a, the water sinking in each arm will force out a jet of water, and if a tube be inserted into this hole it will represent an artesian well, and the water will rise in it till all three are on a level (fig. 2). Instead of these tubes there is a layer of some porous material, as oravel, at some distance beneath the surtace of the earth, rising at each end and forming a sort of basin (fi?. 3), which u 2 292 EX&TXEEEiyG TiVOEKS. is bounded above and below by some impervious substance as clav or stone : the well being sunk at any part (as at a, h, or c) below the level of the gravel, where it forms the surface of the earth, must cut through the upper stratum of clay or stone, and thus form a tube into the porous gravel which holds FIfi. 3. the water : this water is obtained from the rain, which, falling on the surface of the earth, drains tlirough the gravel and fills its lower part. The water will rise in the bore at a height according to circumstances, if the gravel at each side of the bore rises to higher ground, a jet of water will be forced out, if not so high, the well will only partly fill, and so on. Artisian wells are sunk or bored by means of insti'uments screwing on to the end of a set of iron rods each scre^\Tng into the end of the other as shown in fig. 4. The first piece is generally a sort of gouge (r/) two or three inches wide, and so made as to bring up a cylindrical piece of earth when forced in and screwed round, the weight of the rods after a few pieces are added is sufficient to force the gouge iato the earth, except iu stony places, when a sort of " pick " is used. The official report of G-eneral Desvaux on the artesian borings executed in the Desert of Zahara of the p^o^^nce of ConstantiDe, iii 1856-7, states, " that a spring afford i rig 4010 quarts of water per minute, was the result of one of the borings, and that others aftbrding 35, 120, and ENOi:?fEEIlING WORKS. 293 4,300 quarts respectively were successively completed." And he goes on to say : " When the shouts of the soldiers announced the gush, tlie Arabs sprang in crowds to the spot, lanng themselves in the welcome abundance, into which mothers dipped their children ; while the old Sheik fell upon his knees and wept, returning thanks to Allah and the French. At Gum Thioiir a well sunk to the depth of 170 metres and yielding ISO quarts a minute was at once taken as the centre of a settlement by a portion of a previously nomadic tribe. . . As soon as the water appeared they began the construction of a village, the plantation of 1,200 date trees, and entirely renounced their wandering existence." According to General Desvaux's report, these artesian wells are likely to have a most important influence on Arab life, and greatly to subdue the roving propensities of many of the tribes. MIXES. !Mines are excavations made in the earth for the purpose of raising the various minerals which exist below its surface, such as coal, rock-salt, and the various ores from which metals are extracted (see " Smelting"). Klines consist of those which contain minerals that lie in strata ^;ff;v///f/ (or nearly so) to the surface of the earth, as coal, rock-salt, or iron-stone, and those containing the ores and minerals which are imbedded in seams or fissures of the primitive rocks, and are nearly perpendicular to the surface. Of the former kind, coal-mines form the chief examples. AVHien indications of coal are discovered, a '• boring " is commenced to ascertain its existence, and the depth at which it is placed below the surface. Each piece of earth raised by the boring-tools is placed one beside the other, in the exact order in which thev are raised, so as to show the kind of earth being bored through, and the thickness of each strata between the surface of the earth and the seam of coal ; and it sometimes happens that the boring is stopped on arriving at certain kinds of rock — the old red sandstone, for example — for it would be useless to continue boring beyond this, no coal ever existing below it. 29i E>'GTXEEIlINa WOEKS. "WHien coal is found, and its quality and the thickness of the seam ascertained to be such as to warrant further expense, a shaft is dug down of some eight or ten feet diameter, cased with brickwork or wood to prevent the falling-in of its sides, and in some cases powerful machinery has to be erected to pump out the water which flows in. On reaching the coal, galleries — called " gates," or "bords " — are dug in it in opposite directions, forming one long straight passage, and from this other smaller ones, called "headways," are dug, at right angles, to the depth of about twenty-four feet, and from these other "gates" are carried parallel with the first, forming a series of roadways joined by short passages, and having squares of coal between them ; the height of all these passages is determined by the thickness of the seam of coal, usually from three to ten feet. The great masses of coal forming the squares between tliese passages are gradually dug away (as far as can be done with safety) and the gates continued onwards, but before long the ventilation becomes impeded, and the air foul and dangerous from " fire-damp " (carburetted hydrogen) or "choke-damp" (carbonic acid), gases which are given ofi* from the fissures in the coal. It is therefore ncessary to produce a continuous current of fresh air in every part of the mine, which is done by sinking another shaft at the furthest part of the mine and keeping a large fire burning at its mouth, over which a tall shaft is generally erected, from which a column of light air ascends, di'awing fresh air down the other shaft and throi;gh every part of the mine, to supply this " up-cast " shaft, as it is called. This supply of fresh air is economised and regulated by doors or valves, so placed that any part requiring extra ventilation can obtain it at any moment by shutting these doors and letting the whole current go through that par- ticular part. The removal of coal is efiected partly by digging with the " pick," and partly by blasting with gunpowder ; a large square mass is cut all round, and a charge of powder fired behind it, so as to bring down at once sixty or eighty tons of coal, which is brought along the gates on " trams " EXGnrEEBlKG WORKS. 295 to the bottom of the shaft, where " corves " or baskets filled with it are dra^Ti up to the " pit's-mouth " by steam maehinerv, one cone ascending full while another is descending empty. The mines from which most minerals, such as sulphuret of lead (galena) or of copper, are dra\m, belong to the second class, or those whose shafts " cut " the vein of mineral at a very acute angle. AVhen the existence of the required mineral and its '' dip " or inclination is ascertained, a shaft is sunk so as to cut its upper surface, and then carried through it, cross-cuts being formed on to the vein, and " levels " or galleries right and left in the direction of the vein. From these levels '"winzes" or small shafts are cut at intervals from one level to that below it, thus leaving square portions of the mineral vein to be explored, which is done by digging away the roof or upper part, so that the rubbish and ore falls down, when it is sorted and carried away. SHIPS. The first part of a ship '• laid down " is the '• keel ; " this is the projection which rims along the whole length and forms the lowest part of the ship. The ship is built in what is called the '" building slip," which slopes towards the water ; in this " slip " a row of oaken blocks are placed at x-^--K'l^^ s r-H . H>>^X ^- a few feet apart, and about three feet high, on which the keel is laid ; these blocks are for the purpose of allowing the workmen to cross from side to side below the keel and to form a foundation for the ship to rest on. In fig. 1, A is this arrangement of blocks, c the BUILDING BLIPS. keel, at the hinder part of vrhich is the "dead wood," or the timbers filling up the space between the keel and the ciirved bottom of the ship, which is more curved than the keel, and very much so towards the " stem " or hindermost part. Across the keel are laid the " floor- timbers " or " ribs," b, which are curved timbers laid at right angles to the keel and passing outwards and upwards in the exact curve which the sides of the ship are to assume ; these are too ciu"ved and too long to be of one piece, others, therefore, are added, and joined end to end with the first by wooden bolts or " dowels ; " these curved timbers are cut to a pattern, chalked on the floor of the "mould-loft." The ribs as they cross the keel are bound to it by a piece of strong timber running along inside of or above them, but parallel to, and exactly over it, which is called the " keelson," and is bolted to the keel through the centre of each lower piece of the ribs or floor-timbers ; it is sho\vn at D, fig. 1. In large ships there are three of these keelsons, running side by side, and forming a strong support to the masts, which rest upon them. At each end of the keel a bar of timber rises, the hindermost being called the " stern- post," and that in front the " stem-post " (marked e and f in fig. 1). Across the ribs on the outside and parallel to the keel, are laid the "planks," which are boards of oak of from two to six inches thick, laid close together and touching at their edges ; these are fastened to the ribs by plugs of EXGiyEERIXG WORKS. 29: oak, called " treenails," going right through the planks and ribs, and wedged at each end (tig. 2). In large ships, similar plauks line the inner side of the ribs, and oblique or diagonal braces are also sometimes used, to strengthen the ship and keep it from curving or " arching " when in the water. The masts of a " ship " are three in number, a " schooner " has two, and a *" sloop " but one. These masts pass right down through the decks, and rest upon the keelson. In small vessels each division is made of one piece, but in larger ships they are made up of a central piece, with others fastened round it so as to enlarge and strengthen it. The first or lower division of the central mast is called the " main " mast, and that above it the " maintop " mast ; the fore mast is divided into '' fore " mast and " foretop " mast, and the at\er mast is called the '* mizen " and " mizen- top " mast, and the pieces above these the " foretop gallant " mast, " maintop gallant " mast, and '• mizentop gallant " iU-ST HOUSE. mast. These masts are made, and raised by craues in a building called a mast-bouse, and placed in the right position in the ship floating beneath. The outside of ships, as high as the " water-line," is covered with a sheathing of copper to defend it from the action of the " worm " {Teredo navalis), which bores into and destroys the wood exposed to its ravages ; the copper also presents a smooth surface to the water, and facilitates the motion of the vessel. At the stern of the ship is placed the " rudder," a wooden construction turning like a door on fastenings, and which, by being moved on one side, presents a greater amount of resistance to the water, and consequently tends to tiu-n the stern of the ship away from that side, thus altering its coiu-se. The decks of a ship are like the floors of a house, running across from side to side, and supported on strong beams bolted into the sides ; they are Kiil'AlKl.Mi UOCK. sliijhtlv arched, to increase their strength, as they have in ships of war to support the weii^lit of the guns, &c. A section of the decks and other parts of a ship is shown at fig. 3. where the general figure and the ditfereut parts described may be seen ; the section is through the middle, from side to side. ^lost ships of any considerable size carry several boats with them, either on deck or suspended between the masts, to serve as a means of escape in case of fire, or any other accident requiring the crew to leave the ship, also as a means of keeping up communication with the shore. Ships of war are named according to the number of guns they carry, as a seventy-four, a huiidred-aud-twenty- gun sliip, &c. AV'hen sliips have to be repaired they are brought into the repairing dock, which has a pair of gates shutting it ort" from the river; when they are closed (at low water) the water is pumped out from the dock, and the repairs done ; when finished the water is let in, and the ship floats out. In small vessels it is sometimes sulUcieut to PADDJ^E AXD SAILIXG SHIP. liaiil tlieni on shore at lii.2;li tide, so that -when the tide is doAvn they may be left hia^h and dry and repaii'ed, and when the tide is at the highest, hauled otf again. Steam ships are constructed to be propelled either by paddle wheels having flat boards fixed to their circumferences, which on being tui'ned roimd, take a great hold in the water, and so cause the motion of the ship ; or by the screw-propeller, which has been described. The ii'on ships, which of late have almost superseded those of Avood, are made of plates of "wi'ought iron, rolled, while red hot, between rollers to the thickness reqmred, which is generally half-an-inch ; these plates have holes punched all round them by machinery, and are united by rivets placed in the holes red-hot and rivetted by heavy hammers. The most magnificent specimen of iron ship- building ever attempted is the Leviathan. This ship is 6sO feet long, and is not made of one thickness or case of ii'on plates, but is upon a new principle called the " cellular," consisting of an outer and inner casing of iron plates held together by partitions of iron so as to separate them into square compartments or " cells." The objects gained by this arrangement are greater strength, and greater safety, for in case of injury to the outer portion, the water woidd EXGiyEEBI>'G AVORKS. 301 outer only between the tAvo in that compartment where the injury happened to be, and so fill only that small portion w ith water. The whole ship is also divided into compart- ments by means of double screens of iron, making it like a fire-proof box, and even if a fire should occur in one of these, the others would be preserved from its eftects. The masts and yards of this great ship are also of hollow wrought iron plates rivetted together, and are both stronger and lighter than tliey would be of wood. A machine is placed at the lower part of each mast which by compressing, can crush it up, and cause it to break ofi" and fall over the side of the vessel in case such a thing should be required, as in a very violent storm ; and the standing rigging, which is of wire-Fope, can be let loose in a few minutes so as to completely free the ship of the mast. This great ship is constructed to be pro- pelled both by screw and paddles ; the screw engines are four in number, and are each of 1.600 horse power, the paddle engines are also four, of 1000 horse power each, l^eing 10,800 altogether. They ■svill require about ISO tons of coal a day to work them ; 12,000 tons of which are capable of being carried. The Leviathan will have six masts, and be able to spread 6,500 yards of sail, -n-ill accommodate 4000 passengers, and when ready to sail, with all on board. Anil weis:h about 25.000 tons. DOUBLE XOCE. CAXALS AXD LOCKS. Canals are artificial water-courses, either for the purpose of connecting rivers, or for forming water communication for the conveyance of goods. There are about 2200 miles of canal- way in England, which is still in complete requi- sition, and but little aftected by the enormous goods traiiic of the railways. Canals atford a means of slow but cheap conveyance for heavy or bulky goods, not requiring a rapid transit, for the more rapid the pace the greater the resist- ance of the water. The usual rate of transit is somewhere about tv\'o-and-a-half miles an hour, at which pace a horse can draw about four times as much on water as he can on a railway, and about thirty times as much as on a level tiirn- pike road ; but if a greater speed were to be obtained, it ia found that the resistance of the water would impede it so much, that at the rate of five miles an hour a horse could EXGiyEEKLN'G WORKS. 303 draw no more than he could on a railway, and at ten miles only a quarter as much. In constructing canals, it is important to have a good supply of water, and this is generally secured by turning all the springs and streams in its course into it. or deriving its source at its highest level from a large river. Tlie same works have often to be constructed on the line of canals that are required on railways, such as bridges, cuttings, embankments, tunnels, &c., and besides these, contrivances peculiar to canals, called "locks," which are now to be described. Locks are barriers or doors constructed so that these artificial rivers may be carried over rising ground and through valleys, without the labour and expense of cutting through the hUls and filling up the hollows as would be required without them. Railways can be constructed on ground which is not quite level without any embankment or cutting, as it is not absolutely required that railwavs shall be perfectly level. But water always -nnll be level, unless it is constantly flowing, as is the case with streams, and these only sink a few inches in a mile, or else thev become so rapid, that if attempted to be imitated in canals, they would be useless ; for it would require too much power to draw any vessel up the canal against such a stream, and would moreover require more water to supplv them than can commonly be obtained. The means therefore adopted to overcome this difficulty are gates, or in other words, a pair of "locks." The canal is constructed in such a manner that it shall be perfectly level for a certain distance, then sink down some t?n or twelve feet at once, and again flow on a level and sink down. These sudden lowerings are effected as foUows : tAvo pairs of thick solid doors of wood are fitted to shut in the water, and another pair a short distance further on ; behind these the bed of the canal is lowered the required distance. AVhen a barge or other vessel has to pass down the canal the first pair of gates are opened, and the barge floated in between them and the second pair, the first i)air are now closed, and the water beyond the second pair being lower, that between the 301 ENGrSfEERlXG •WOEES. gates in "^liieli the barge floats is let out by means of a valve worked by a rack and wheel ; when this valve is raised the water flows out and sinks down to the level of the water beyond, carryiug the barge with it ; in a few minutes it is so low that, the second gates being opened, the barge is drawn out and continues on its Avay. But suppose the barge had to be brought up the canal, then it is floated into the space between the gates (as before), and the one behind the barge closed, the water beyond the gate ia front being higher, is let into the space Avhere the barge is by a valve, and this filling, lifts up the barge to the level of that in front, the front gates are then opened and the barge proceeds onwards. These gates are never made to shut level, but meet at an angle with the point towards the highest water, which is done that they may resist the great pressure which the water exerts, and for turning this to advantage, for this ven' pressure shuts the gates and keeps them close together. The canals which have much traflic on them have double locks, as ia the engraA"ing, that barges may go up and down at the same time Avithout haA^ing to wait for each other. The barges and boats are generally "towed" or drawn by a horse attached to a rope, and walking on a "to-ttTng path" or road at the side of the canal. THE END.