BUREAU OF ORDNANCE & HYDBOGRAPHY, U. S. NAVY. PRAC'i ICE i EXT^EKI..iENTAL B.VTYERY. QJattteU Iniueraitg ffiibratg Strata, Nem ^atk BERNARD ALBERT SINN COLLECTION NAVAL HISTORY AND BIOGRAPHY THE GIFT OF BERNARD A. SINN, 97 1919 olin The original of tliis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924030896983 '■» I'l I IITl'liV' REPORT THIRTY-TWO POUNDER THIRTY-TWO CWT COMMODORE WARRINGTON, CHIEF OF BUREAU OF OSDNAH'CE & HYDROGRAPHY j BY 1,IEUT. JNO. A. DAHLGKEN, V. S. BT. ASSISTANT INSFECTOK OF ORDNANCE. 18 4 8. WASHINGTON: u. ALEXANDER, PRINTER, 1850. )LL -^^ — ■ PRIKfTED BY OKDEE OF THE CHIEF OF BUREAU OF ORD. & HYDROG. saassK Ordnance Office, U. S. Natt Yard, Wttshmgton, Mvemher 1st, 1848. Commodore L. Warrington, Chief Iff Bureau of Ordnance and Hydrography: Sir: — Herewith I submit the record of the progress made to this time in the practice at the Experimental i Battery : chiefly with a view of giving the ranges and re-' coils of the 32 pdr, of 32 cwt,, when chambered and un chambered, whiph it is understood are desired by the ^ Bureau for pomparigon. It will be seen that in range the unchambered piece J excels the chambered in every case. By no cogsidSraN ble quantity it is true, and differing so little from the variations occurring in the individual results as to admit of no final deduction from a single comparison, But being uniformly constant in every case, does justify the conclusion that the chambered gun is slightly inferior to i the unchambered in range. The recoil is very considerable in both guns, but greater in the unchambered, the ratio being 4 to 5. With the chambered gun is- to be had a diminished re- coil, and greater thickness of metal around the charge. With the unchambered, a straight borg that requires no complipation of rammers aqd sponges, and which in the heavier ships removes the necessity of cylinders of dif- ferent diameters. The unchambered gun is in all probability strong enough for any service that it can be put to. The practice shows that the breeching and bolts were capable' of withstanding at least two hundred rounds on a horizon- tal platform. The strain, however, was very great, and ' *when increased by the rolling motion of the ship, and the in'clination of the deck in firing to windward, it may perhaps be deemed necessary to use some means to di- minish it. The tables furnish the distance at whifh each shot fell from the gun on the water, thereby affording the means of estimating the intrinsic value of all parts of the work. The manner of doing this is by the Plane Table as stated in the report made to the Bureau on this subject in November, 1847. It happens to be the only means that can be resorted to at this place for the determina- tion of ranges; there being no part of the shore of the Eastern Branch that can be used for the purpose, and it is believed to furnish the simplest and most ready method, while it is not inferior to any other in the re- quisite accuracy. To test its capability in this respect, two Plane Tables were placed on either side of the line of fire, each entirely independent of the other, and from the results given on page 50, it will be seen how they coincide in estima- ting the position of the shot. In comparing them, it must be borne in mind that the jet of water does not always present the same well defined object. When calm, it rises in a thin and distinct column ; but when the wind is strong, it presents a confused mass, and hence thedifficulty then in estimating it with precision, The variations in range are moderate when the atr mosphere is undisturbed ; but whenever the wind pre- vailed from any quarter they were increased very much. And it was under these circumstances that the practice was often prosecuted, in order to meet the wishes of the Bureau by accelerating the w^ork. It rarely occurred that more or less of the woollen cylinder was not left in the gun after its discharge. The importance of removing these fragments entirely will be readily appreciated, as life or limb -may be peril- led by omitting to do so ; accidents from this cause are not common in the U, S. Navy, but still they do happen sometimes, and must exercise an unfortunate influence on the gun's crew when this is the case. Other Navies do not seem to have attained greater security in this respect than ourselves. Col. Charpen- tier* in his essay on ordnance, says: "The deplorable accidents that have occurred from premature discharges on board the gunnery frigate Iphigenie, the steam frigate Asrnodee, the Diadem line of battle ship, and the cor- vette Boussole at Acapuico in Mexico, cannot fail to attract attention to the causes of these disasters, by which many men have lost their lives, &c." In the practice at this Battery it is observed that the fragments of cylinder left in the gun, consist always of a portion of the bottom seam, and occasionally parts of the single stuff that is connected with it. It is probable that if the material were manufactured into cylinders, the absence of seam would reducethechances of any residuary fragments, and consequently the liability to casualty. I am strongly impressed with the belief, however, that premature explosions may generally be traced to the inexperience or carelessness of the sponger, and that the best remedy is in training him carefully to his duty in real practice. To complete the details of this gun, there are required the higher degrees of elevation, the extreme distance at which its shot or shells penetrate sufficiently to be availa- ble, and the adjustment of sights to the several ranges': * Of the French Marine Artillery. this work will be prosecuted as rapidly as may be con- sistent with accuracy. Lieut. Blunt having been detached at the commence- ment of the practice, his place was supplied by Passed Midshipman A. N. Smith. The detail at the Battery was assigned to gunner Clapham, and the Plane Table work was executed by the ordnance mechanics. DETERMINATION OF STATIONS FOR THE PLANE TABLE. The Eastern branch of the Potomac presents some advantages for obtaining the ranges of guns, in connec- tion with the proposed plan of applying the Plane Table to determine the grazes from the jets of water made by the impact of the shot. The entire distance to the Virginia shore, from the Battery, is about four miles, affording range for guns of any calibre. In front of the wharf is the narrow chan- nel, and beyond it an extensive flat, which nothing can cross but boats. Vessels passing in the channel beyond, are never long in the line of fire selected, and the little water on the flat admits of stakes and screens being readily planted for the adjustment of the sights. On both sides of the stream, points for Plane Table stations are at hand, and these were to be determined as a necessary preliminary to the proposed use of the Plane Tables. The delineations of the shores which could be had, furnished nothing but the outline and the positions of a few prominent objects ; they were, thierefore, not availa- ble for the present purpose, and it became indispensable to measure a base, and to determine the points by a series of triangles. After a hasty reconnaissance, the longest line conve- nient to the river was selected by Lieut. Blunt on the southern shore, and a suitable base of verification sub- sequently obtained in the Navy Yard. The site of the. principal base was not of the best description, lying partly across a low marshy piece of soil which gave much trouble ; the remainder was on cultivated ground, and along a smooth beach overflowed at high water. On the 25th of April, the ineasurement of this principal base was begun and continued on parts of the 26th, 27th, and 28th, as the weather and state of tide admitted. The remeasurement took place on April 29th, and May 1st. 1 Many unfavorable circumstances interposed, but never- theless the difference between the two measurements did not quite equal one foot. In one instance a bar was knocked over, and in the remeasurement, fractions of bars were allowed, which should have been avoided, as so many sources of error. ' First Measurement, - - - - 2567,474 feet; JRemeasurement, - ... - 2568,466 " Difference, -'--.--- .992 " Mean, .--.---- 2567.970 " 10 The base of verification was measured on the 22d of April ; this lay in the Navy Yard, and nearly East and West ; the East end but a few feet from the ship house ; the West end near an old gun on the wharf, and both ends in line with station D. The ground nearly level, firm and unobstructed. The first measurement gave 1010.227 feet ; the remeasurement 1010.197— the dif- ference about one-third of an inch. The main series consisted of five triangles well con- ditioned. The angular measurements were made with a Theodolite (Gambey,) belonging to the coast survey, for the loan of which I am indebted to the politeness of Professor Baches This operatiota resulted sufficiently well for the pur- pose in view. Inasmuch as the base of verification proves to be, feet. By calculation from principal base, - 1010^325 By two measurements, 1010.212 Leaving a difference of one inch and thirty-six hun- dredths. The Gambey Theodolite being required in the coast survey, the angles of the secondary points connecting with the main series were measured by a small Theodolite of the old English construction, reading no less than 30". 11 As might be ' expected it gave but indifferent angles, though by frequent repetitions the errors in them were reduced sufficiently for the object in view. The measurements of the bases were made by a sim- ple and speedy process. Two wrought iron tubes, pur- chased for rocket cases, were put on a lathe, and the ends turned with accuracy to certain lengths, intended to be ten feet and fourteen feet, respectively, though on close examination they proved to be slightly in excess. The tubes were of the best metal, two inches exterior diameter, and one-tenth of an inch thick, without any perceptible flexure. Each tube was supported by two stands that permitted it to have a vertical movement, and was thus made hori- zontal by means of the level placed on the surface planed for that purpose. The alignment was preserved by sighting through the tubes in both directions upon the pegs that marked the base. The whole arrangement was of the simplest character. 12 MAIN SERIES. Base 2567.970 feet 3.4095899 O ' " 11 Buzzard Point 53 18 14.0 Base North 60 48 17.75 Base South 65 53 47.0 + 18.75 Buzzard Point— Base North 2923.5 Buzzard Point — Base South 2795.8 7.8 11.5 40.7 o ' " " D 54 18 29. 27.6 Buzzard Point 46 04 57. 55.6 // Base North 79 36 38.25 + 4.25 36.8 D— Buzzard Point 3540 . 6 —Base North 2592.9 Ver'n Base West 62 44 11.25 04.3 D 63 17 47.5 40.5 // Base North 53 58 22.25 +21.0 15.2 Verification Base West — D 2359.1 —Base N. 2605.9 0.0959349 9.9409890 9.9603738 3.4658986 3.4465138 3.4658986 0.0903575 9.8575343 9.9928201 3.5490762 3.4137904 3.4137904 0.0511503 9.9510114 9.9077973 3.3727380 3.4159521 13 A 65 23 09. Base North 70 24 41.75 Ver'n Base "West 44 12 13.75 + // 07.6 40.2 4.50 12.2 1998.4 2700.4 3.4159521 0.0413739 9.9741075 9.8433620 A— Base North —Verification Base West 3.3006880 3.4314335 3.4314335 0.0016176 9.5714101 9.9807285 O ' " Ver'n Base East 85 03 35.62 A 21 53 12.75 Ver'n Base West 73 03 32.75 + 28.6 05.7 21.12 25.7 2592.9 St 1010.325 Ver'n Base East— A —Ver'n Base We 3.4137796 3.0044612 1010.325 feet. 1010.212 " 1.36 in. Verification Base deduced by triangulation from Base, By two measurements, (mean) Diflference 14 SECONDARY POINTS. O ' 1' 3.4658986 B 94 15 32 0.0012009 Buzzard Point 43 55 01 9.8411184 North Base 41 49 27 B— Buzzard Point 1954.9 9.8240261 3.2911256 —Base North 2033.4 3.3082179 / // 3.4137904 B 90 34 26 0.0000217 D 51 38 23 9.8943847 Base North 37 47 11 B— D 1588.8 9.7872616 3.2010737 —Base North 2033.3 3.3081968 O 1 II / // 3.4137904 Bat'y Port No 4 56 35 45 35 54 0.0784010 Base North 60 58 55 59 04 9.9417539 D 62 24 52 —28" Battery— Base North 2752 . 9 25 01 9.9476006 3.4397920 — D 2716.1 3.4339453 15 o ' " II 3.4339453 A 41 00 16.5 21 0:1830063 Battbry 100 28 20 25 9.9927031 D 38 31 09 —14.5 -A— Battery 2578.1 14 9.7943454 3.4112970 — D 4070.6 3.6096547 ' // 11 3.4397920 B 47 57 54 56 0.1291618 Battery 33 15 54 56 9.7391927 Base North 98 46 06 —6" B— Battery 3663.1 08 9.9948938 3.5638476 —Base North 2033.0 3.3081465 O ' 't fi 3.4397920 F 58 24 30 26 0.0696658 Battery 46 58 12 08 9.8639074 Base North 74 37 30 +12" F— Battery 3116.2 26 9.9841699 3.4936277 —Base North 2362.5 3.3733652 16 o ' " II 3.4397920 G 31 44 30 40 0.2789058 Battery 29 04 44 53 9.6866823 Base North 119 10 18 —28" G— Battery 4568.6 27 9.9410850 3.6597828 — BaseNoith 2543.2 3.4053801 6 ' II t II 3.4397920 H 24 31 24 30 0.3818575 Battery 24 00 57 01 03 9.6096111 Base North 131 27 21 —18 H— Battery 4970.4 27 9.8747410 3.6963905 —Base North 2699.4 3.4312606 O ' " It 3.4397920 I ,37 42 35 34 0.2134918 Base North 109 52 48 48 9.9733158 Battery 32 24 39 +02" J— Base North 2412.3 38 9.7291504 3.3824342 —Battery -4232.5 3.6265996 17 3.6265996 ' " II Buzzard 36 19 12 08 0.2274738 I 131 35 42 38 9.8738254 Battery 12 05 18 +12" Buzzard— I 1496.4 14 9.3209776 3.1750510 —Battery 5344.4 3.7278988 3.5490762 ' II II 31 43 36 28 0.2791508 Buzzard 121 38 18 10 9.9301319 D 26 38 30 +24" 0— Buzzard 3019.0 22 9.6516409 3.4798679 — D 5732.7 3.7583589 3.4798679 O 1 II II P 32 05 30 34 0.2746669 133 41 48 52 9.8591347 Buzzard 14 12 30 —12" P— 1394.9 34 9.3899931 3.1445279 —Buzzard 4108.4 3.6136695 18 O ' 11 II 3.4798679 R 34 56 12 07 0.2421102 112 36 39 34 9.9652707 Buzzard 32 27 24 +15" R— 2829.2 19 9.7296839 3.4516620 — Buzzard 4866.9 3.6872488 O 1 II II 3.6136695 R 53 06 42 38 0.0970212 P 108 38 36 32 9.9765944 Buzzard 18 14 54 +12" R— P 1608.4 50 9.4957078 3.2063985 ' — Buzzard 4867.3 3.6872851 19 BATTEHY. The Battery is placed near the edge of the wharf; it represents the deck and side of a ship, excepting that one half of the former is adjusted as nearly as possible to a level, upon which the recoils are measured that are given in the record. Finding that the least motion, even of the man who attended the coin, was sufficient to disturb the elevation of the gun, it became necessary to adopt some means of avoiding the inconvenience ; for this purpose the plat- « form nearest the port was cut away so as to make place for a bed of solid timber, placed on the ground, and high enough for its upper surface to coincide with the plane of the platform ; the separation was coinplete but not so great as to present the least hindrance to the carriage- trucks during recoil. It is very evident on considering the appliances con- nected with the reaction of the gun, that no inconsidera- ble variation must be expected in the extent of the re- coil. The axles, trucks and platform, are of wood, con- sequently liable to be influenced by every change of atmosphere, and to be worn by the violence of the action. When the platform was new, the material of which it 20 is composed warped sometimes, and being laid at right angles to the line of recoil, each plank formed a. kind of gutter ; this, when removed by the adze, presented smooth surfaces over which the gun moved more easily than before, if fired soon afterwards. This cause operated occasionally in a slight degree during the practice with both guns ; but once only to such an extent as to vitiate the results entirely. This occurred with the chambered piece, (June 1st, 1848,) and necessarily caused the rejection of the recoils on that day. The height of the axis of bore above the water is always given. According to the draft of a section of the sloop of war St. Louis, obtained from the Bureau of Construction, it appears that the height of her guns is less than seven feet above the load line. A height somewhat greater has been assumed, be- cause the ship would never be depressed to this point, except when leaving port with a full supply of provis- ions and water. Seven feet and a half have been pre- ferred as the probable distance of the battery from the water under the ordinary circumstances of cruising. The motion of the ship will preclude the possibility of this being an essential point within certain limits, and in any case, the difference of range due to height decrea- 21 ses with the range itself, in a very large ratio. At a thousand yards a single foot will not make a diiference of 10 yards in the range. The tide rises and falls about 5 feet, and the time of firing is chosen, so as to have the difference between the water and the axis of bore conform as nearly as pos- sible to 7^ feet. The wind always exercised a disturbing influence on the direction and ranges of the shot, and every effort was exerted therefore to make use of a calm atmosphere. The Battery was protected by a roofing over its whole extent, and at one end was a stout upright pole with two arms, the positions of which, variously combined, served to telegraph to the observer any directions that might be necessary. ♦ 23 GUNS. One of them has an 18 lb. chamber, it is marked No. 41, and is from the West Point Foundry. The details according to the draught are : Inches. Diameter; of Bore - - - - . . . . 6.40 " ofCharnber 5.29 Length of " 7.00 " of Slope (or junction) - - - 2.50 " total of Bore (including chamber) 75.10 Diameter, of Vent - - 0.20 Distance of " from bottom of Chamber 1.54 Inclination of Vent - - - - 8° from vertical. The external orifice of the vent, after 405 rounds, vsras enlarged to 0.25 in., and the surface of the metal immediately around it, was indented as much as five hundredths of an inch, by the action of the hammer. In Bouching, a half inch drill was first passed through, and impressions of the vent taken at every inch. The en- largement of the vent appeared to be very gradual"; about one inch from the bore its diameter was three-tenths of an * inch, and here it increased suddenly, so that the orifice at the bore required at least a circle of three-fourths of an o 23 inch in diameter, to include the irregular channellings which, at this part, were very deep ; they extended the whole length of the vent, diminishing in depth with the enlargement itself. As the removal of metal weakens the gun, something would have been gained hy bouching after 300 rounds. The length of the bore in this gun, was 74.95 in. ; its weight 3764 lbs., and preponderance 312 lbs. The greatest wear in the bore was between the 63d and 65th inch from the face of the muzzle, and just about the vertical axis of the projectile when in its place ; this was apparent to the eye, as well as one or two slight scores in the middle of the bore; otherwise it offers a smooth surface to the view. MEASUREMENTS BY STAR GAUGE. From fape of Muzzle. m. 65.45 .25 .00 64.75 .50 After Proof. After firing 249 Shot. €.418 After firing 405 Shot. 6.40 .419 .428 .429 .433 Wear of bore. 24 MEASUREMENTS BY STAR GAUGE— Continued. Prom face of Muzzle. After Proof. After firing 249 Shot. After firing 405 Shot. Wear of bore. in. 64.25 6.432 .00 6.412 6.418 .430 .018 63.75 .430 .50 .429 .25 .423 .00 6.416 .423 62.75 .421 .50 .491 .25 .418 .00 . 6.412 6.415 .416 .004 THE UNCHAMBERED GON, Resembles the former, except that it has no chamber. It comes from the Richmond Foundry, weighs 3783 lbs., and is marked No. 4. The vent shows externally but little enlargement.' The inner orifice, however, is considerably worn. On the surface of the bore a circle of 0.75 in. diameter would include all the grooves, decreasing thence so suddenly that at 0.30 in. from the bore, the diameter of the vent is not more than 0.33 in., and nefarly circular — the groovings of little depth. measurements by the star gauge show the wear of the bore. Prom face of After firing Muzzle. 400 shot. 73.00 6.40 71.00 .410 69.00 .418 68.00 .420 66.00 .422 65.50 .424 65.00 .422 64.75 .425 64.00 .425 63.25 .426 63.00 .428 . 62.50 .428 62.25 .426 « 62.00 .424 61.25 .423 60.50 .422 60.00 .421 59.50 .419 58.00 .417 54.00 .416 48.00 .417 42.00 .414 30.00 .412 7.00 .414 .-.- ' ..' 1 36 Specimens were taken from the muzzle of each gun, and gave the following results : Tensile strength Density- per square inch. No. 41, West Point, - - - 7212 32900 No. 4, Tredegar Foun'y, Rich. 7155 25600 '27 GUN CAHEIAGES. That which served through nearly the whole prac- tice was of the class ordinarily used afloat for the 32 pdr. of 42 cwt., there heing none in this yard for the 32 pdr. of 32 cwt. The dimensions are : Height of cheek ----- - . Length " Axle-arms (diam.) Weight -------- -- Width between cheeks, front. - - - - " " " rear - - Fore Truck, (diam.) Rear " - - ■■ The chambered and unchambered guns were mounted on it in turn. It had never been previously put to any service, and when laid aside, had withstood about 700 shotted rounds, without requiring the least repair in any part, nor was it then incapable of farther service. The recoil had been unchecked in some 500 cases, and a breeching used for the remaining 200. On the 20th of September, a carriage for guns of this 2H m. 57 U 54 K 1040 lbs. 20i in. 22 ii 20 c< 18 u 28 class was completed from the designs furnished for that purpose. After 60 rounds, the cap-squares proved to be too light, having been forced upwards, so that in one, the iron was opened at the joint ; they were | of an inch thick, those of the first carriage were jV in. The common ship coin was found to be entirely un- suitable for elevating the gun with the exactness re- quired. It was replaced by one of Lieut. J. H. Ward's construction, which proved to be well adapted to communicate the most delicate motion that could be desired, and strong enough to endure the whole of this practice uninjured. The only liberty I have taken with his design, was the substitution in one coin of a counterpoise on the handle, and in the other, of a circle in Heu of the handle ; as the tendency of the breech in firing the gun, was to force the coin out, and in certain positions of the handle, its weight assisted this in some degree. In service the circle will probably be found to interfere with the block of the training tackle. •29 POWDER. The powder was made by the Messrs. Dupont, express- ly for this practice ; it was directed to be of uniform strength, and not to exceed the average standard pre- scribed by Regulation. From barrel No. One, 500 grains Troy, were taken and weighed into samples of 10 grs. Five of these were found to contain 66, 64, 57, 63 and 50 ker- nels. The least number in the fifty* samples was 39 kernels and the greatest 93. The mean of all, 60 kernels in the 10 grains Troy. From No. fourty-four, 100 grains weighed into sam- ples of 10 grs. each, gave 86, 93, 97, 99, 101, 101, 111, 112, 120, 129. Mean 105 grs., in 10 Troy grs., and varying from 86 to 129 grs. From this it would seem that the average size of grain in the latter barrel was considerably smaller than in the first barrel. The number of grains assigned by the Ordnance Manual to cannon powder, is 150 in 10 grs. Troy. The proof by Eprouvette, made at Norfolk by Com- mander Dornin,inthe ordinary manner, gave 293 yards 30 as the mean of forty trials. The minimum being 256 and the maximum 321 yards. The residuum left near the muzzle of the piece, con- sists almost invariably of large blotches of a crimson or dark red color, spread thickly on the lower side of the bore, and extending 12' to 15 inches within, the smoke obscuring farther view of the bore. This deposite (sulphuret of potash) is noted by good authority, as a most favorable indication of the quality of powder. 31 CYLINDERS. These are of the Regulation flannel, a stout twill- ed fabric, and according to contract should be en- tirely of wool. The diameters correspond to those recommended by Major Mordecai,* as best adapted to permit the maximum effect to the charge, viz : 4.6 in. for the 18 lb. chamber, and 5.5 in. for the 32 lb. un- chambered. The body of the cylinder is made straight with a single seam, and the bottom sewed to it. The length of those for the chambered gun, when filled, was about ,7^ in., the neck increased this to 8 in., which was the length of the bore generally occupied by the charge. The filled cylinders for the unchambered 32, were 5.8 in. long ; their greater diameter produced less com- pactness than that of the charges for the chambered 32, and the least compression in ramming, forced the neck in on the powder, causing it- to require no additional space in the bore. Owing to the stoutness of the material, and the man- ner of making the cylinders, they retain their shape. •Experiments on Gunpowder. 32 and never assume that of a mere bag, as those made of common flannel in the usual form are apt to do. It is observed that remnants of the cylinder, equal to 1 or 2 square inches, are invariably left behind, and in- clude some portion of the bottom seam. The sponge crushed and removed much of the frag^ ments, but the small scraper usually brought out mor6, and seemed perfectly reliable in this important particular. Excentric 32 pdr. StielL. Concentric 5? pdr. Shell. 33 PROJECTILES. The mean windage allowed by the Navy Regulations to shot and shells is >15 in., and the founder is required not to depart from this more than .03, more or less. The Gauges, therefore, by which the 32 pdr. shot are inspected, are 6.22 and 6.28. In this practice the shot and the excentric shells were not allowed to differ from the mean windage more than one hundredth of an inch, and their greatest and least diameters were accordingly, 6.24 and 6.26. The con^ centric shells being cast expressly for the purpose, the number could not be conveniently increased so as to ad- mit of gauging to the above limits, and therefore, the Regulation Gauges 6.22 — 6.28, were used. By these, a number was selected from the stock on hand, weighed, and like weights classed in sets of ten. It rarely happens that the metal in shot is homoge- neous. In many hundreds that have been examined, I have not seen more than two or three in which the evidence of unequal density was not decided, and this varies very considerably in amount. The densest part of the shot was ascertained by float- ing them in mercury, and. strapping them to sabots. having the heavy points of a set in similar position, so as to avoid, as far as practicable, any effect on the range and direction, that might arise from variation in this particular. It vfas found difl&cult to choose shells of like weight, even from a large number, and hence it will be noticed that some irregularity in this respect was unavoidable ; the extent is. probably unimportant. They were strapped and fitted like those used in ser- vice, excepting the charge of powder, which it would not have been safe to use, in firing from this Battery, as there is no certainty of the direction nor range of the fragments, and persons passing ashore or on the water, might have been injured. The shell was charged with a few ounces of powder, to blow the fuze, and the remainder of the cavity filled with rice, the bulk of which differs in weight but little from that of powder. Fuzed shell filled with powder, - - 26.44 lbs, " " " " rice, - - - 26,34 " The sabots were of the dimensions prescribed by Regulation. It would probably be found very useful on shipboard to use sabots with shot ; they could be stowed around the hatches and in racks, as conveniently as if without 35 sabots, and in case of getting adrift would not be apt to roll about the decks. In firing, the process of loading is more convenient and rapid than with any kind of wad, and in cases of emergency the charge and shot can be sent home with one motion. In the usual practice of keeping the guns loaded for sea, a hard wad will be put over the shot, the sabot being between it and the charge. There is little doubt that the variations of shot, in range, are less when fired with sabots than with wads. LOADING. After the gun has been fired, a line coinciding verti- cally with the hind part of the cheek, is marked on the platform and the recoil measured. The piece is run out, by the side tackles, and a moist sponge entered, one dry sponge, and then another follow, in order to remove the dampened crust and to dry the bore ; lastly, a small scraper which draws out any frag- ments that may yet remain on the lower side of the bore, for it is observed that they generally lodge there. A swab is used to wipe the muzzle and as far as the arm can reach within, so as to present a clean surface to the edges of the quadrant bar. The cylinder is pushed home gently, neck out and seam clear of the vent: followed by the projectile. If shells are used the fuze hole is kept up and in the verti- cal plane ; they seldom go from the muzzle to their place without some inclination of the fuze hole to the right or left, but are readily restored to position by the ladle. The gun is brought into line by the sights. The bar in the rear of the base ring has a small perforation about 37 three hundredths of an inch in diameter, the middle sight is notched and a wire stretched across it. The quadrant is adjusted, the required elevation given, and if no vessel be in the Avay, the signal is made to the plane table and the piece discharged. Neither shot nor shells have beckets ; when it be- comes necessary to withdraw them from the gun, no difficulty has ever been experienced in doing so with the ordinary ladle. 38 THE ELEVATION Is obtained by a quadrant made especially for this service. Its principle of construction is simple. It consists of a steel bar about four feet in length ; at the end of it is an arc, (12 in. radius) the index of which bears a spirit level. Outside of this is a smaller level, and in- side, a bar of 12 inches length, both at right angles' to the main bar. The bar is placed on the lower side of the bore, and entered into, the gun until the cross bar coincides with the muzzle face. The cross level is adjusted to the inferior surface of the main bar, the principal level to zero on the arc. The exactness with which the new Navy ordnance are manufactured, ensures the desired means so far as the gun is concerned, and no pains were spared to have the elevating instrument executed in the best possiblie manner. The first which was made, failed to answer the pur- pose. The principal bar was of brass, and unable to support the arc and its appliances ; a flexure in it was soon indicated by the standard bar. The divisions of 39 the arc being on silver, were quickly rendered undis- tinguishable by the fumes of the powder during practice, so that it became impossible to verify the position of the index after a few rounds. The motion of the tangent screw was imperfect, &c. Another one, therefore, became indispensable, and was iiaade by Mr. Wiirdemann. As might be expected from the attainments of this artist, its character is in all respects of the highest order; the arc is divided (on platina) into 5' and subdivided by the vernier to 5". The centering, clamping, tangent movement, interior surface of level, and adjustment of level, graduation, &c., &c., are in all respects equal to those of the best instruments for angular measurements of like radius. Previous to the commencement of the practice on any one day, the quadrant is laid on a standard bar, the cross level adjusted to the inferior surface of the main bar, and the index level to zero. In practice the main bar rests on the lower side of the bore, the cross bar coinciding with the muzzle- face. The bubble of the cross level is brought to its place by gently turning the bar around in the gun, ■which is then raised or depressed until the index level indicates the proper elevation. 40 THE PllIMER In its form and principle resembles the French, but differs in the details of fabrication. It consists of a quill gauged a little smaller than the vent and filled with fine grained powder. It is surmounted by a cap of thin pasteboard, containing fulminate of mercury combined with a small portion of mealed powder. Finding that the rim of the pasteboard cap broke the force of the blow and caused occasional failures, I sub- stituted different material for it, and reduced the charge of fulminate also.* ' *After enduring a year's trial very satisfactorily, this primer was adopted for the service by order of the Chief of Bureau. 41 The cap of pasteboard -was generally coated with shellac colored black. The new h#ad with uncolored shellac, and the barrel of the quill also, by which the primer was so well preserved as tp remain several hours in water and yet explode. This t«sst the old primer would not withstand, and was also objectionable on ac- count of the fragments of the }iea4 being thrown oflP violently by the explosiaa. In one instance, the eye- lid of a man was cut severely, so pauch so, that had the eye itself received the wound, it would probably have been injured irremediably. When primers are used, the cylinder is niever pierced, they have been found powerful enoijgh to penetrate more than one thickn^s,^ of Regulation flannel. 42 LOCK, &c. The guns were discharged by the common Watch and tube during the shell practice, and with the lock (except on one occasion) when shot were fired. The interval occurring before the transmission of the flame' to the chargie from thftube was very evident, while the action of the percussion lock seemed instan-' tane'ous. The Bureau is already apprised that the distinctive principle' of the hammer fitted to these guns is in no re- spect similar to that of the sliding lock prescribed by Regulation. It performs its function with certainty^ perfectly unmoved by the gaz that escapes through the vent. Another form of lock piece already submitted to the Bureau may be very advantageously substituted for that which has been in vogue so' long. This will receive any of the caimon percussion locks hitherto used, and their action remains as complete and efficacious as at present, while they are far better protected from acci- dental injury that may disable them. The strap now made to attach the hammer to the lock piece will thus be dispensed with, and as its cost 43 is perhaps more than one-half that of the whole lock, the e^penjditure in that proportion is avoided ; an object truly never to be considered in ordnance at the expense of efficiency^ but which may be very properly taiceninto account when this is fully attained. 44 DETERMINATION OF THE MNGES. It has already been stated that the locaUty ofiered no means of projecting the shot on the land : it became necessary, therefore, to prosecute the work on the water, and the plane table was selected as likely to furnish the greatest facilities for this purpose. It was obvious, however, that the usual appliances for sighting objects in field work would not answer. The variations in distance, of shot projected with like elevation and equal charges, were believed to be too considerable to be included within the circumscribed field of the telescope, and hence many of them might escape the observer. The ordinary alidade was also incapable of being aligned with rapidity and certainty on the column of water thrown up by the shot, and at the same time preserved on the point representing the station of the observer. Arrangements were made, supposed to be suitable to the peculiar requirements of the case, and preliminary practice instituted to test their fitness. The results were sufficiently favorable to warraiit the belief that the plane table thus altered was susceptive in practised hands of all the exactness that was desjra]3le, and it has ^mm«mmmmmm^^mmF Pla-uc Taliip. k .Vlidadp,. 45 been used ever since at the experimental battery with the addition of some improvement in the method of no- tation. The new Alidade may be described as a flat metallic ruler supporting a column, at the head of which is another ruler having a vertical movement only *, its ex- treme points are fitted wili raised sights (a notch and a point), which collin^ate with the beveUed edge of the lower ruler. An extension of metal occurs about mid- way and (abreast of this column) at tJie side of the lower ruler, which is perforated to receive the head of a pin, so that tiie bevelled edge coincides with the centre of iiiis perforatioiL, Near one Cf the corners of the plane table a small brass pMe is countersunk in the wood and tapped so as to receive a pin about half an inch long and screw-cut, hav- ing a milled head, above which is a continuation of the pin tWD-teiths of an inch in length, turned perfectly smocrth, so as 1» pewnit the lower Tvler to pivot about it as a centre. While prepapation is being «iade at the battery for pifaiCtice, the observer is sent witk a plane table to a station, the direction to which, from the point on the line of fire where tJie first grazes are eKpected to tjccur, is at jright angles or raiearly so, to the line of fire. tmmmtmi^^^ 46 The table is adjusted with the small metal plate over the stake that marks the station, levelled, and the screws made to bear as firmly as possible. The observer places his alidade on the pivot pin, sights carefully on a given poinrat the battery, and marks on the paper affixed to the table, the direction assigned by the bevelled edge of the ruler; each of the stakes planted in the line are noted in the same way, and the observer then makes known that he is ready. On the nearest end of the ruler is screwed a pin with a suitable head for the fingers of one hand, for the purpose of giving the direction. On the farthest end is a thin slide carrying a small lever with a keen cutting point, which is depressed by the action of a spring for- cibly enough to make an incision, on the paper ; the slide is moved to a convenient distance on the ruler, and clamped there by screws. The preparatory signal is made at the battery by hoisting a large white ball displayed against a black ground ; seeing this, the observer brings round the ali- dade to the expected direction of the first graze, extends his unemployed hand and presses the lever, so as to raise the cuttingedge abovethe paper. When the ballislower- ed, the piece is fired. The instant the jet takes place, the sights of the alidade are aligned upon it, and the 47 Gutting point of the lever suffered to make aft incision in the paper. A plane table is placed rearward of the gun on a pro- longation of the line of fire, and by it the deviation of tte ball from the line of fire is determined. Very little elementary information is required to per- ceive that the line connecting the battery and the station is a base from which is determined the position of a given point, in the present case a column of water, and that the projection of this base on any scale will enable one to ascertain in terms of that scale the distances of the jet from either end of the base ; that from the bat- tery being the one in question. The efforts of the person at the plane table in the rear, to ascertain the deviations at the first graze, were frequent- ly rendered unavailingby the intervening smoke. But as the line of sight from the table for range, intersects the line of fire nearly at right angles, the deviation of the [projectiles from the line is not sufficient to cause any I appreciable error in estimating the distance from the i battery on the assumed line of fire. The failure, therefore, in this respect, only involved the loss of the lateral deviations, which was remedied sub- sequently so far as regarded the more important distan- 48 ces, by the practice at screens through which the shot were fired. As these deviations were small proportionally to the variations in range, I attempted to measure them by means of a micrometer fitted to a telescope ; the fixed wire being adjusted to the line of fire, and the move- ment of another wire made to depart from it, right or left as might be necessary. The faintest smoke, however, even when not entirely impervious to the naked eye, ob- scured the lenses completely. If it had been possible to place a table in the line of fire beyond the range of shot, the deviations could have been noted without fail, but the locality put this out of the question. When the work has been completed, the table js re- turned to the office, and a projection made of the line of fire from the base formed by the station and battery, in doing which the pin used for the alidade is unscrewed and another .subs.tituted which has jio head, and screws with the upper surface to a level with the paper; on this 49 the centre is shown by a point ; the various stakes are laid down on the line by means of the directions as-i signed them from the station occupied, and the distan ces from the battery thus determined, serve to verify the accuracy of the observer ; they having been previously ascertained by the Theodolite. The grazes are then transferred to the line, and their respective distances read off by a scale, the bevelled edge of which is divi- ded into yards. The scale found to be most convenient on a table oil ordinary dimensions is ^^jJ^^. Hence oneinch=: 200 feet, \ and 1.5 in.i= 100 yards; the lowest subdivision ^ two yards, but the eye readily estimates to half a yard. The beam compass used for projecting, reads by the vernier to the hundredth of an inch, and may be estimated to one-fourth of this quantity. The accuracy which the plane table thus arranged, is capable of, may be exemplified by the following deter- minations of grazes from different bases, one being on each side of the stream. 50 Chambered 32 pdr. f 32 cwt.) JUNE FIRST. JULY SIXTH. D. A. B. ' G. Yards. Yards. Yards. Yards. 535 532 1082 1083 539 538 1073 1074 555 556 1076 1074 570 573 1097 1097 516 517 1159 1157 519 517 1098 1097 545 546 1093 1091 519 519 1058 1057 584 585 1069 1069 563 564 1176 1178 544.5 544.7 1098.1 1097.7 The difference between the means is altogether ina- mate'rialj and that occurring in individual cases may be properly attributable to the character of the object, which is not always very clearly defined. The employment of more complex instruments with a view to closer determinations would involve the ne- cessity of a more highly instructed order of observers, and the results would probably afford no compensation for the trouble. 51 The arrangement of the plane table as described, places its adjustment and use within the scope of any person of intelligence and precise habits. The obser- vations recorded in this report were made by persons employed in the mecheinical department of the ordnance | workshops, and initiated by me with a slight prepara- tory training. As a knowledge of the plane table was not within the line of their vocation, it could not be ex- pected that they should have been conversant with the rationale by which results wete to be obtained from its application ; but it is certain that in its employment, they manifested a degree of dexterity which it would be dif- ficult to excel. In one case, seventeen grazes in rico- chet were taken in succession at one table. The results are deduced so readily, that it has rarely happened that the operations in any practice were not recorded on the same day on which they were made ; and this with slight exception was the work of one person. Many other methods will suggest themselves by which the jet of water may be determined, and more closely than by that now described ; but it will also be found that they are inferior in convenience and ca- pacity. The measurement of an angle will require an observer skilled in the various adjustments and uses of instruments, and necessitates subsequent calcuk- 52 tion. The reading of divisions on the arc, limits the observation to the first graze, and produces the liability to error in noting quantities, that is so apt to occur to the most experienced, and when this happens, the ano- malous character of the observations leaves no data for the correction that is admissible in the uses to -which angular measurements are applied, either for terrestrial or astronomical purposes. 53 MEANS OF RESULTS. With all the exactness that it was possible to use, so that the practice in every instance might be made under I circumstances, as nearly alike as possible, it -will be seen that the variations of the shot are considerable, and that there are often in a series one or more cases of extraordinary departure from the average of the dif- ferences between the other rounds. When this arose from any unusual incident that might be considered as the cause, such as a disturbance of the elevation, the round was rejected; but these anomalies took place oftener when they could not be traced to anything connected with the manipulation at the battery, and would, of course, improperly affect the mean result more or less. When excessive there could be no hesitation in rejecting them, but there were cir- cumstances wherein some method seemed necessary, in order to prevent a merely arbitrary disposition of the cases in question which might seem objectionable. For present purposes I have been content to exclude the greatest or least round, which differed from the next more than twice the amount of the average varia- 54 tion. If by this process the series was reduced too much in number, another series was fired. It often happened that the practice was interrupted by the springing up of a strong breeze which impaired the regularity of. the ranges in a considerable degree. When this was the case, the series was repeated, EANGES OF SHOT FROM THIKTY-TTTO Pdrs. OP THIRTY-TTTO Cwt. CHAMBERED AND UNCHAMBERED ; Charges 4^ lbs. (Dupont's Powder.) Gauges gf Shot 6.24—6.26. 1848. The deviations are only noted at the first graze. 56 UNCHAMBEEED 32 of 32 cwt. No. 4. Bore Level. Weight of shot 32 . 63 lbs. Heavy spot up. Clear; wind S.W. light ; afterwards shifted to N.W., blowing strongi June \5th, 1848. °1 ll DEVIATION. GRAZES. Recoil on Level • Platform, Right. Left. First. Second. Third. Feet. Feet. Yards. Yards. Yards. Feet. : 1 7.2 Lost. 263 Lost. Lost. 22 31.1 , 2 .3 Lost. 308 Lost. Lost. 25 28.8 3 .4 4 275 631 Lost. 22 30.0 4 .5 4 323 719 1282 22 30.7 5 .6 1 275 669 999 12 30.7 6 .7 1 259 814 1219 19 30.2 7 .8 4 271 870* 1111 13 29.5 8 .8 4 309 1002* 1413 10 30.4 : 9 .9 4 305 1195* 1562 5 31.4 10 .9 4 281 Lost. 1209 5; 31.8 7.6 287 708 1256 30.5 Gun fired with Lock. A chet shif high t thS comi regular ,- ed and fr after the Tiencement, the water was slightly rippledj and the rico- , -the shot moving in line. At the 6th round the wind eshened, causing them to deviate to leeward and to bound , first graze, making but few ricochets. ♦Rejected. 57 CHAMBERED 32 of 32 cwt. No. 41. BoRB Level. Weight of shot, 32.69 lbs. Heavy spot up Weather cloudy; light breeze from S'd. and E'd.; water smooth. 1 July 12th, 1848. J" V . 1. DETIATION. GRAZES. it 1^ Recoil on Level Platform. Right. Left. First. Second, Third. Feet. Feet. Yfirds. Yards. ■Yards. Feet. 1 7.2 Lost. 279 603 21 22.4 2 .3 (c 274 703 15 24.0 3 .4 (.( 287 763 12 24.2 -.4 .5 3.9 260 677 18 22.3 *5 .6 1.2 268 653 i 23 22.6 6 .7 Lost. 274 629 ■t 17 24.0 7 ,8 1.2 257 837 s 12 24.8 8 .9 1.2 281 Lost. ^ 14 24.1 9 8.0 Lost. 261 ti 14 22.9 10 .1 1.8 263 609 16 23.8 7.7 ,270 684 23.5 Gun firec with Lock. * In bounding from 1st Graze, this shot cut off the head of a pole (574 yards from the battery,) 14 inches above the water. 58 UNCHAMBBRED 32 of 32 owt. No. 4. Elevation of Bore 1°. Weight of shot, 32 .56 lbs. Heavy spot up Weather overcast ; light breeze from N'd. and W'd. ; water slightly rippled. October 19JA, 1848. (U H DEVIATION. GRAZES. ■° 9 2; Recoil on Level Platform, Right. Left. First. Second. Third. Feet. Feet. Yards. Yards. Yards. Feet. 1 8.0 0.67 561 970 14 28.9 2 .0 5.5 531 1011 13 27.3 3 7.9 6.0 584 10^0 14 28.9 4 .8 2.0 602 986 § 16 28.6 5 .8 '0.1 608 979 3 12 29.2 6 .7 5.1 600 1015 ^ 14 29.8 7 .6 *701 *1273 12 30.6 8 .6 3.3 629 907 13 29.3 9 .6 1.7 569 915 17 29.4 • 10 •5 ' 548 978 12 28.8 7.8 581 977 29.1 Gun fired nrith Match. . * Irregular : rejected. » CHAMBEEED 3S of 32 cwt. No. 41. • Elevation of Bore 1°. Weight of shot, 32.63 lbs. Heavy spot up. Weather clear wind moderate . from N'd. and W'd. ; water slightly June 1st, 1848. <^ ^ "1 II u r DEVIATION. GRAZES. S'2 1"' Recoil on Level Platform Right. Left. First. Second. Third. JieJ. Feet. Yards. Yards. Yards. ■ Feet. 1 7.3 Line. 533 30.9 2 .3 7 538 29.2 3 .3 9 556 29.1 4 5. .4 .4 Line. 572 516 1 g 1 30.8 31.0 6 .4 6 518 1 f^ 31.6 7 .5 2 545 32.0 8 .6 3 519 31.9 9 .7 3 585 30.7 10 .8 Line. 563 31.7 7.5 545 30.9 Grun fired with Lock. prevj e platforn ous to thi a having been i s firing : hence jvarped by the weat the greater recoil ; her, had been smoothed it is rejected. 60 UNCHAMBBEED 32 of 32 cwt. No. 4. Eletatioh op Bore 2°. » Weight of shot, 32 . 63 lbs. Heavy spot up. Wind Kioderate from S. W. ; water slightly rippled. June 3d, 1848. * = g > DEVIATION. GRAZES. 1" Recoil on Level Platform, Right. Left. First. Second. Third. feei. Feet. Yards. Yards. Yards. Feet. 1 •6.8 Lost. 875 30.8 2 .9 *914 31.4 3 7.0 Lost. 841 31.0 4 .3 Lost. 836 g 31.5 5 .4 10 880 •1 31.4 6 .5 Lost. 839 -^ 32.7 7 .7 5. 831 33.8 8 .8 5 84S 31.2 9 .8 5 878 33.0 10 8.0 5 883 32.3 7.4 857 ■ 31.9 Gun fired with Lock. »Irre gular : rejected. ,=.-.• , .,., _„,_ . . , 61 1 • CHAMBERED 32 of 32 cwt. No. 41. Elevation of Boke 2°. Weight of shot, 32.69 lbs. Heavy spot up . eioudy ; -wind light from N'd. and WM. ; water smooth. Juhf 13th, 1848. zips CO DEVIATION. •" ' GRAZES. Recoil On Level Platform Right. Left. First. Second. Third. Feet. Feet. Yards. Yards. Fords. Feet. 1 6.8 Lost. 816 1183 11 22.1 2 .9 4 859 1490 1890 8 25.3 3 7.0 Lost. *911 1337 1645 12 25.2 4 .1 9 875 1510 1875 10 24.8 5 .2 Lost. 830 1428 1804 12 24.6 6 .3 4 819 1331 1664 12 23.8 7 .4 9 851 1253 1451 11 23.3 ' 8 .5 3 830 1350 1643 10 25.1 9 .6 Line. 865 1353 1675 10 24.8 10 .7 5 851 - 1305 • 1577 11 22.6 ; 7.3 844 1354 1692 24.2 : Gun fired wit! I Lock. •Irr 3gular : rejected. 62 UNCHAMBJLEEU 32 of 32 cwt. No. 4. Elevation of Bore 3°. Weight of shot, 32.63 lbs. Heavy spot in. Weather clear and calm : water smooth. Jme 16th, 1848. 2;« S 6 DEVIATION. CRAZES. e4H S o Recoil on Level Platform. Right. Left. First. . Second. Third. fee*. Feet. yards. ■ Yards. Yards. Feet. 1 6.8 Line. 1118 1557 1794 5 30.0 2 .8 14 1128 1531 1703 4 29.7 3 .9 Lost. 1141 1559 1738 6 30.1 4 .9 Line. 1133 • 1579 1803 8 30.3 5 7.0 Lost. 1108 • 1545 1743 5 29.0 6 .1 it 1187 1597 1781 6 31.3 7 .2 ti 1118 1555 1747 5 30.8 8 .3 (( 1182 1602 1818 5 31.8 9 .4 (( 1113 1571 1797 5 31.0 10 .5 5 * 1170 1541 1667 3 32.3 7.1 1140 1564 1759 30.6 Gun fired with Lock. 63 CHAMBERED 32 of 32 cwt. No. 41. Elevation op Bore 3°. Weight of shot, 32 . 63 lbs. Heayy spot in Weather calm and cloudy at commencement. Water smooth. | July 6th, 1848. = § "' g DEVIATION. GRAZES. 14 Recoil on Level Platform, Right. Left. First. Second. Third. * Feet. Feet. Yards. Yards. Yards. Feet. ■1 8.2 27 1082 Lost. 1708 4 22.8 2 .1 Lost. 1073 . 1450 1668 5 24.2 3 .0 cc 1076 1483 1702 10 25.0 4 7.8 8 1097 1513 1688 6 23.1 5 .6 Lost.' 1159 1633 1851 7 22.9 6 .5 t 1098 1508 1710 9 24.9 7 .4 (( i 1093 1500. 1705 5 22.8 8 .2 (C ■ '. 1058 1542 1789 8 23.8 9 .1 (( 1069 1513 1727 6 22.3 10 .0 17 1176 1610* 1827 9 24.0 7.6 1098 1528 1738 23.6 Gun fired with Lock. 64 UNCHAMBERED 32 of 32 cwt. No. 4. Elevation op Bore 4°. Weight of shot, 32 . 63 lbs. Heavy spot in. Weather clear. Wind from S. W. strong. JwM nth, 1848. lU n-O o , DEVIATION. GRAZES. Recoil on og Level Platform. Right. Left. First. Second. Third. Feet. Feet. Yards. Yards. Folds. Fee^ 1 6.8 Line. Index started. 31.1 2 .9 14 1387 1428 1 31.6 3 7.0 Lost. 1387 1502 1 32.8 4 .3 ti 1420 Lost. 2 30.8 5 .5 (i 1375 1480 2 30.3 1 6 .6 t( 1349 1397 1 30.0 7 .7 it 1383 1391 1 30.9 8 .8 14 1371 1398 1 30.2 9 .8 Lost. 1443 Lost. 2 31.0 I 10 .9 cc 1465 1524 1 Lost. ^ 7.4 1398 1446 31.0 Gun £red with Lock. 65 CHAMBERED 32 of 32 cwt. No. 41. Elevation op Bore 4°. Weight of shot, 32.56 lbs. Heavy spot in. July 10th, weather pleasant ; light airs ; water smooth. 11th, weather cloudy; light flaws from N. E. ; water perfectly smooth. 1848. ■1 DEVIATION. GRAZES. Recoil on Level Platform. Right. Left. First. Second. Third. 1 2 3 . 4 5 6 7 8 9 10 Feet. 8.5 .4 .3 .3 .2 .0 .1 .2 .3 .3 Feet. Lost. 6 Lost. 63 32. Yards. 1377 1321 1320 1324 1316 1373 1357 *1236 1351 1397 Yards. 1521 1491 1527 1450 1574 1695 1427 1617 Yards. 1544 1513 1592 1653 2 2 2 1 2 3 2 3 3 3 Feet. Breech, on. 22.5 23.3 24.2 22.9 23.6 24.1 23.0 23.6 23.8 8.3 1348 1538 1576 23.4 Gun fired with Lock. •Irregular. Rejected. "^"^ 9 66 UNCHAMBEEED 32 of 32 cwt. No. 4. Elevation of Bore 5°. Weight of shot, 32 . 63 lbs. Heavy spot in Weather' quite calm ; water perfectly smooth ■ Jme 22(J, 1848. > .2-B, h3 Distance at which fuzes took effect 1597 & burst. 1369 Ft. 21.5 21.3 21.8 Chocks 9.9 Free. 23.8 23.8 23.3 8| ' 23.0 12 24.8 vsi.^ Yds. 1241 1597 1333 1687 1412 WEIGHT OF SHELL. (SOUCHEDi) Us. 24.94 25.13 .00 24.88 25.06 .13 .25 .31 .28 .34 Additional. 1454 25.13 Us. Powder. 0.19; Rice . . 0.66, Fuze . . 0.30 Sabot,&c. 0.55 1.70 Powder. 0.13 Rice . . 0.72 Fuze . . 0.30 Sabot,&c. 0.55 1.70 This set was fired alternately with the Excentric Shells at the same elevation One shell burst too soon on the 14th. 75 EXCENTRIC SHELLS. Gauges 6.24 — 6.26. Five second Fuzes. Elevation 2°. August 3d. Weather cloudy and perfectly calm. August 14th. Weather cloudy and damp ; light airs from N. E. 1848. DEVIA- a WEIGHT OF SHELL. -a M o TION. o if MS Distance (boughed.) h (3 H o d at which fuzes took effisot. 1 « E ■a g i & ■ P. S Additional. a < M h^ '£ m Eh ^; v; w Ft. Ft. Fife. Yds. Ft. Yds. Lbs. Lbs. i' 8.3 Lost. 948 1434 & burst. 2 21^ 25.13 Powder . 0.19 2 7.5 IC 1047 20.7 1333 EC Rice . . 0.63 3 .3 ct 940 1 21.5 Chocks 1379 « Fuze . . 0.30 4 .2 it 965 10.1 1465 K Sabotj&c. 0,55 5 .0 " 994 4 9.8 Free 1412 (( 1.67 6 .0 it 954 4 22.5 25.06 7 .2 9 1015 6 23.3 Cf Powder. 0.13 8 .7 12 1088 10 24.3 " Rice . . 0.69 9 .8 15 803 11 23.4 ti Fuze . . 0.30 10 8.0 12 1048 10 23.6 ei Sabot,&o. 0.55 ( 23.6 7 *) 980 1424 1397 25.10 1.67 i 10.0 1 On 3d, one si lell bui Bt too soon. On 14 i, two shells bu St too S( )on. • 76 1 CONCENTRIC SHELLS. , Gauges 6.22-^6.28. Five second Fuzes. , Elevation 3°. Weather cloudy ; wind light from N'd. and E'd ; water slightly- rippled. ^vgust llth, 1848. 13 a 0) > ■ql DEVIA- TION. GRAZES. T3 {= 1 ■s o §1 ^1 Distance at which fazes took effect. WEIGHT OF SHELL. (BODCHED.) o Si bo e i o t 'a s Additional. ■< Pi *A iS to Eh- fc5 ■ tj w Ft. Ft. F o , DEVIA- TION. GRAZES. 4 1 6 SI Distance at which fuzes took effect. WEIGHT OF SHELL. (DOUCHED.) d to •a i s Additional. 1 9.8 Ft. liOSt. Yds. 1353 Vis. 4 Ft. Chocks 5.0 Yds. 1520 u 25. 13 Lis, Rice . . 0.69 2 .8 27 1304 1893 7 5.4 1460 Powder. 0.13 3 .7 6 1169 1592 2 5.3 1555 Fuze . . 0.30 4 8.5 57 1389 9.0 1554 Sabot,&c. 0.55 5 .5 8 1191 6 .2 1245 1.67 6 .8 Lost. 1358 .4 1760 7 .8 °& at which fuzes toolf o DO !4 ■Ko, t i .1 ■s S effect. t Additional. » < p:i >A fa m e »4 PI H Ft. Ft. Yds. Yds. Yds. Ft. Yds. Lbs. Lhs. 1 6.8 Lost. 1384 1 22.5 Not seen. 24.78 Powder 0.13 2 .8 Lost. 1417 22.8 In water. 25.16 Kice . . 0.72 3 .9 Line. 1418 1 23.6 .06 Fuze . . 0.30 4 .9 Lost. 1459 4 23.8 4th graze .19 Sabot,&o.0.55 h V.ll ti 1422 1 22.9 Not seen. .03 ' 6 .1 Smoke interve- ning. 1390 3 23.9 After 1st graze. .13 1.70 V .2 1415 1 22.8 Not seen. .00 8 .3 " 1453 2 23.3 .03 9 .4 tl 1384 1 23.4 (( .13 7.0 1416 23.2 25.06. Four shells exploded prematurely. 79 1 EXCENTRIC SHF,r,T„S. 1 Gauges 6.24— 6.26. Ten second Fuzes. Elevatioji 4°. Cloudy ; wind light from N'd. and E'd. ; water slightly rippled. August mh, 1848. ■a § & •= 6 is, h ■H < DEVIA- TION. GRA.ZES. § o 1 Distance at which fuzes took effect. WEIGHT OF SHELL. (BOOOHED.) 1 5 1 Additional. 1 Ft. 7.8 Ft. 36 pas. 1574 5 Ft. Chocks 10.4 Yin. Not seen. X6s. 25.13 Lbs. ^ Powder. 0.13 2 .8 25 1757 3 9.8 4th Graze. ec Rice . . 0.69 3 .9 9 1720 2 10.3 in water. £C Fuze . . 0.30 4 8.0 12 1461 2 9.4 Not seen. <.i Sabot,&c. 0.55 5 .1 93 1908 2 9.7 3d Graze. te 1.67 6 .2 60 1584 * 5 9.6 6th Graze. it 7 .3 Lost. 1616 4 10.2 Not seen. EC 8 .5 ti 1951 4 11.2 u t( 9 .6 (t 1827 3 12.5 4th Graze. ii 10 .7 IC 1375 12.5 Not seen. cc 8.9 1677 10.6 25.13 The excessive irregularity of this series induced the repetition of it, which will be found opposite the next page. The explosions were not visible from the Plane Table station ; a bluff point intervening. 80 CONCENTRIC SHELLS. Gauges 6.22— 6.28. Ten second Fuzes. Elevation 5°. Weather hazy; calm at commencement : watersmooth. Au^st nth, 1848. 1 1. > 11 ■so, DEVIA- TION. Grazes. 1 1 "s 6 §1 Is Distance at which fuzes took eiTect. WEIGHT OF SHELL. (BOUOHED.) i ■A •J ■a ■ i: s Additional. Ft. JS. yas. rds. Ft. Yds. Lbs. Lis. 1 6.5 60 1651 22.6 25.31 Kice . . . 0.72 2 3 .3 .2 48 27 1631 tl648 1713 1 23.5 23.8 Exploded near gun. .31 .34 Powder . 0.13 Fuze . . 0.30 4 5 .2 .2 LOEt. *1780 1666 1847 1 24.8 Chocjks .22 .31 i3abot,&c.0.55 1.70 6 .2 (c 1657 8.8 .13 7 .2 (C 1641 9.0 .25 8 .1 cc 1650 1 9.0 .38 9 .1 63 1645 1693 1 8.8 .25 10 U .1 .1 6.2 Lost. *1706 *]575 1 8.8 Free. 23.4 .19 .06 1649 1751 ^ 23.6 25.27 I 8.9 *Ifregular — rejected. tEx)ilosion premature— rejected. • 81 EXCENTRIC SHELLS. Gauges 6.24—6.26. Ten second Fuzes. Eletation 4°. Cloudy; calm at commencement; water smooth. .August 18th, 1848. DEVIA- TION. Ft. 7.8 .5 .4 .3 .1 .0 6.9 .8 .6 .5 .4 7.7 Ft. Lost. 102 I ( line of metal ) 10 929 1178 50 10 1560 1214 100 10 2550 1414 140 10 3145 104 The Gunnade appears to have a trifling but uniform advantage over the Canon-Obiisier. Where the axis of each guri is horizontal, the ratio of velocities given by the second gun to those of the first is 0.975, which is indeed very little below unity. The diflerence does not exceed the errors of the ex- periments. End of the Extract. 105 Comparison of Ranges given by the Canon-Obusier and Gunnade, and by the U. S. Chambered 32 pdr. of 32 cwt. P.B. lo 10' 2° 12' 50 Canon-Obusier - 307 601 1493 Grunnade ■■ - 306 929 1560 U. S. Chambered 32 of 32 270 595 895 1544 Chambered 32 of 32 with CanOn-Obusier — 37 — 6 +51 with Gunnade — 36 — 34 — 16 Contrasted with the 32 pdr. of 32 cwt., it will be perceived that the Frpnch Gun has greater length of bore, and is 400 lbs. lighter. Its charges are about one and a half ounces less, shot two-thirds of a pound heavier, and the windage slightly greater. The ranges are great- er at point blank, which may be attributed to the piece being placed one-third higher, for at 1° where this cause is less operative, the ranges are nearly equal, and at 5° where its effect must be inappreciable, they are inferior. As regards recoil, it seems from the trials made in 1835, on board the Dryade frigate by a board of officers, that they considered it desirable to diminish its violence, both in the Gunnade and Canon-Obusier of 30. They preferred the latter piece however; for though the Gun- nade gave a better range, and had some advantage in appearance, it was more excessive in its recoil and ac- | 106 tion, which was attributed to the less suitable position of the axis of the trunnions, it being in the same plane as that of the bore, while that of the Canon-Obu- sier was below it. But this could not account for the increased ranges of the Gunnade, by supposing that the projectile received an increased elevation from its action, because according to the Gavre practice, the " angle de depart," from the Gunnade was inferior to that from the Canon-Obusier. * If the construction of pieces, and the circumstances connected with the projection of the shot be considered, I think it will be admitted, that similar causes were in action to produce the same relation of ranges and re- coils in the Gunnade and Canon-Obusier, that has been noticed in the two pieces which form the subject of this record: and when the Ballistic Pendulum intended for this station is completed, I shall expect to obtain from its results, a verification of those now submitted. It is stated by recent authority,* (1845,) that %. 1838, (three years after the trials on board the Dryade,) the French Department of Marine issued to the Naval Arsenals the draught of carriage adopted for the Canon- Obusier: which is nothing more than the ordinary ship carriage without the rear trucks; thus supplying friction on the deck for modifying the recoil. 107 *" L' adoption sur les hatimeiats de guerre du Canon Obusier de 30 a donne naissance a plusieurs especes d'affnts pour cette bouche a feu, parmi lesquels celui qui ne differe de Vaffut marin ordinaire pour canon de 18 court que par un peu plus de longueur et par la suppression des roulettes de Parriere, remplaces par des eckantignoles et celle de I'essieu, auquel on a substitue une entretoise, est aujourd 'hui seul reglementaire. II ne doit done en Hre construit d^autres pour cette piece dans les arsenaux. On le nomme affut a echanti gnoles pour Canon- Obusier de 30, ou communement afftit a double crosse. Le trace en a ete envoye dans les ports en 1838." mm OF ORDNANCE & HYDROGRAPHY, 0. S. NAVY, PRACTICE EXPERIMENTAL BATTERY t PAH.T 1 IRST WA3HIWGT0N: C. ALEXVNDE.), PRINTER, IbSO.