“From experiments made at Metz, in 1834, it appears that masses of cast iron, above one yard square and thirteen inches thick, do not resist the shock of balls fired against them with even moderate velocities, having been fractured not only at the point of contact, but also at points considerably distant from thence. It was found, also, that the side of a traversing gun carriage of iron was broken by an 8-pounder ball, having a velocity of 492 feet; which proves that carriages of this nature would, if struck, be rendered unserviceable: and that a collision, which, with a wooden carriage, would have damaged only an accessory part, without requiring its being replaced, would, with a cast-iron carriage, have a more fatal effect. Not only is the object struck destroyed, but the fragments scattered in different directions are highly dangerous.
“During the year 1850, various experiments were made on board the ‘Excellent,’ at Portsmouth, in order to ascertain the effects which might be produced on iron vessels by shot, both solid and hollow, with various charges of powder; for which purpose a double target, ⅝ of an inch thick, consisting of iron ribs and plates, resembling the opposite sides of a strongly-built iron steamer, was constructed, at the distance of about 450 yards from the ship. The general effect was, that the target was always pierced by the shot, and that numerous splinters were detached from it in every direction, which could not fail to be most destructive to the crew of a vessel of this description; the shot was, besides, almost always split in pieces by the shock. One 32-pounder shot broke into thirty-four fragments. Some experiments were made with grape-shot, fired from a 32-pounder, with charges of 3 lb. and 6 lb., when the shot passed through a plate, making a clean hole 3 inches in diameter, and knocking out some rivets. The effects produced by 6-inch shells were not greater than those produced by shot. Two of these being filled with powder, and having the fuze holes plugged up, broke on passing through the plate; the powder, however, did not explode, but was seen to go away in a cloud like dust.
“From the above-mentioned experiments, it may be concluded, that the splinters detached from the side of an iron ship, and the fragments of the shot themselves, would as effectually clear her quarters as the explosions of shells; in either case the effect would be more serious than any that could be produced by like means on a ship constructed of timber, incendiary effects excepted. With both raking, and diagonal firing, the effect is described as being most formidable; the holes, which were very irregular, were in all cases larger than the shot.
“In 1838, experiments were made at Gavre with two solid balls fired at once against a butt of oak timber, in order to determine the different penetrations of the shot, and the distances between their centres at different distances from the piece. Three different natures of ordnance were used: a long 30-pounder gun, a cannon obusier of 30, and a 30-pounder carronade. One ball was in contact with the charge, and the other in contact with the former. From these experiments it was evident that the ball which was in contact with the charge had the least velocity, and the least penetrating power. It is further remarkable that, at distances beyond 200 yards, the vertical dispersion greatly exceeds the horizontal dispersion.”
Excentric spherical shot.
“Experiments with these projectiles were carried on at Metz in 1841; the following were the effects observed:—When the centre of gravity was above the centre of the figure, the ranges were the longest, and when below, the shortest; when to the right, or left hand, the deviations were also to the right, or left. The mean range of a 12-pounder brass gun, which, with the usual shot, was 1640 yards, was, with the shot whose centres of gravity and of figure were not coincident, the centre of gravity being upwards, equal to 2140 yards, being an increase of 500 yards.
“When the centre of gravity is not coincident with that of figure, the projectile is made to revolve, ab initio, on the former centre, thus occasioning a compound motion in the flight of the projectile. When the centre of gravity is below the axis of the bore, the front must turn from below upwards, and a rotation in this direction continuing, the range will be diminished. In like manner, when the centre of gravity is placed on the right, or left hand of the axis of the bore, the shot will turn on a vertical axis, and produce deviations to the right, or left hand respectively. Experiments were carried on at Portsmouth, and at Shoebury Ness, in the year 1850, to ascertain whether the deviations of excentric projectiles were so regular as to admit of being allowed for in pointing the gun; and whether any result might appear to disprove the maxim, that spherical and homogeneous projectiles are the truest in their flight.
| Nature of | Charge. | Eleva- | Nature of | Greatest | Deviation. | ||
| Ordnance. | tion. | Projectile. | Range. | ||||
| At Portsmouth. | |||||||
| lb. | Deg. | Yards. | Yards. | ||||
| { | 8 | 2⅛ | {Common Shot | 1200 | 2 to 6 | ||
| { | {Excentric | 1450 | 2 to 7 | ||||
| 32 Pr. | { | 10 | 2½ | {Common | 1654 | 2 | |
| { | {Excentric | 2108 | 6 to 27 | ||||
| { | 12 | 12 | {Common | 3100 | 10 to 58 | ||
| { | {Excentric | 3710 | 10 to 150 | ||||
| { | 10 | 2½ | {Common | 1035 | 2 to 3 | ||
| { | {Excentric | 1181 | 2 to 7 | ||||
| 8 inch | { | 10 | 5 | {Common | 1750 | 2 to 4 | |
| { | {Excentric | 1980 | 9 to 21 | ||||
| { | 10 | 10 | {Common | 2800 | 2 to 25 | ||
| { | {Excentric | 3230 | 6 to 54 | ||||
| At Shoebury Ness. | |||||||
| { | 8 | 2½ | {Common | 1296 | 8⅖ | ||
| { | {Excentric | 1750 | 16 | ||||
| 32 Pr. | { | 10 | 2½ | {Common | 1404 | 6¼ | |
| { | {Excentric | 1776 | ⅓ to 5⅔ | ||||
| { | 10 | 12 | {Common | 3068 | 68 | ||
| { | {Excentric | 3498 | 186 | ||||
| { | 10 | 5 | {Common | 1820 | 16⅖ | ||
| 8 inch. | { | {Excentric | 2207 | 19⅓ | |||
| { | 10 | 10 | {Common | 2703 | 35 | ||
| { | {Excentric | 2339 | 141 | ||||
“The preceding table presents, in an abstracted form, the results of the experiments at Portsmouth, and Shoebury Ness. It will be observed that the ordnance used were 32-pounders, and 8-inch guns; from both of which natures were fired the ordinary solid shot, and also shot rendered excentric by the removal of certain quantities of metal. Thus, in the Portsmouth experiments, 1 lb. of metal was taken from each 32 lb. shot, and 3 lb. from each 68 lb. shot; in those at Shoebury Ness, 1 lb. or 2 lb. were taken from the 32 lb. shot, and 4 lb. from the 68 lb. shot.