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ous crew in the turret and running in the gun in order to load it by hand, only the 38-ton gun could be carried. As it is quite possible that the Inflexible will be armed with even more tremendous weapons than the 81-ton guns, this has been held in view in designing the ship; and, by a slight modification, it will be possible to mount in each of her turrets a pair of 160-ton guns, with a length of 30 feet and a caliber of 20 inches. The armament of the Inflexible will be composed of four of the heaviest guns (except those making for the Italian vessels) ever constructed, of which the experimental 81-ton gun completed at Woolwich and tested is the type.* Figure 2 is a sectional sketch of the gun, showing the arrangement of the wrought-iron coils welded around the massive central steel tube. This tube, which forms the core of the gun, is bored out of a solid ingot, which cost £1,700. The bore is 24 feet long, and rifled from the muzzle to within a short distance of the base of the tube, where the unrifled portion forms the powder-chamber. The greatest external diameter of the gun is 6 feet, and at the muzzle it is 2 feet in diameter. The full caliber of the piece is 16 inches. The experimental gun was first bored out to 14 inches and tested; for a second series of experiments it was given a caliber of 15 inches, and then bored to the full caliber of 16 inches and finally tested.

The gun is rifled with 13 grooves, each having an increasing pitch from 0 to 1 in 35 calibers. The service powder-charge is 370 pounds of 1.5 inch powder. The weight of the projectile for the service-shell is 1,700 pounds, and the bursting charge about 100 pounds of powder. The details of the series of proof-trials at Woolwich, also the tests at Shoeburyness, have been widely published. Still, for reference, it is believed advisable to give here the results of the trials last made with the caliber of 16 inches, that at which the gun is to be used in actual warfare:

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*The largest rifled piece previously manufactured is the Krupp gun, exhibited at the Vienna Exposition, and subsequently exhibited at the Centennial Exhibition. It was mounted on a wrought-iron sea-coast carriage, having steel hydraulic recoil-cylinders. This gun is a breech-loader, and is built up with steel hoops over a steel tube. Its weight, including the breech-loading apparatus, is 56 tons. The length of the tube is 26 feet 3 inches. The length of the bore is 22 feet 6 inches, and the caliber 14 inches. The twist is uniform.

The projectiles consist of both steel and chilled shells, and long fuse shells 2.8 calibers. The heaviest projectiles, when charged, weigh, the steel, 1,124.5 pounds; the chilled, 1,157.5 pounds; and the powder-charge of the gun is 242.5 pounds for steel and chilled shells, and 275 pounds for long fuse shells.

Mean pressure
in gun.

Total energy de

veloped.

The experiments for range and accuracy were conducted at Shoeburyness, and are reported to have met the unqualified approval of the authorities. When the last experiments were concluded, viz, October 4, 1876, the 81-ton gun had fired 140 rounds, and it may be interesting to summarize the amount of ammunition that has been thus expended. "With its normal caliber of 14.5 inches it fired 4,660 pounds of powder and 27,052 pounds of iron in 21 rounds. With a caliber of 15 inches it fired in 32 rounds 8,223 pounds of powder and 45,712 pounds of iron. With the same caliber, but with a powder-chamber of 16 inches, in 21 rounds it disposed of 6,020 pounds of powder and 30,810 pounds of shot. With its present uniform bore of 16 inches, and while at Woolwich, it fired 8,870 pounds of powder and 45,981 pounds of iron in 27 rounds. This gives 27,773 pounds of powder and 149,555 pounds of iron expended at Woolwich in 101 rounds. At Shoeburyness the gun has fired 39 rounds with 14,430 pounds of powder and 66,300 pounds of iron. This gives a total number of 140 rounds, 42,203 pounds of powder, and 215,855 pounds of iron."

During the experiments for range, shells were reported to have been recovered from a minimum distance of six miles; others were traced still farther, until deep water arrested the progress of the explorers.

What the 81-ton gun can do against an armored target has yet to be practically demonstrated, a target now being in course of construction for this purpose, and it is expected the tests will be made during De cember. As, however, some important results have been achieved with the gun, which comes next below it in magnitude, viz, the 38-ton of the pattern mounted in the fore turret of the Thunderer, and manufactured for the Dreadnought, also designed for the Agamemnon and Ajax, it may be interesting for reference to state as a matter of fact that the 38-ton gun has sent its projectile nearly through an armored target of the following combination: A 12-inch plate, an 8-inch plate, 6 inches of teak, and a 5-inch plate, into which last it penetrated 2 inches, or altogether 22 inches of iron and 6 inches of teak. In another instance, the projectile was sent through a target built up in the following manner: A 4-inch plate, an 8-inch plate, 6 inches of teak, a 5-inch plate, 6 inches of teak, and an inner 1-inch skin, supported by angle-irons, making altogether 18 inches of iron and 12 inches of teak. This was done at close quarters. Besides, in October last, at a range of 70 yards, the projectile was sent nearly through a target composed as follows: Three plates each 10 feet wide, 8 feet high, and 63 inches thick; between the plates were 5 inches of teak-backing, making the total thickness of the target 29 inches. The shot, which had a striking velocity of 1,421 feet per second, punched a clean hole 13 inches by 123 inches in the two front plates, and penetrated into the rear plate, where it broke up. The charge was 130 pounds of 1-inch pebble-powder, and the projectile weighed 812 pounds. The target was an exact sample of the armor of some of the English coast forts; therefore, as a prelude to experiments on a larger scale, this experiment opens up the question of coast-defense.

Some idea of the amount of ammunition required for the 81-ton gun may be formed when it is estimated that in an action, if the Inflexible would fire only ten shots from each of the four guns, she would use ap 14,800 pounds of pebble-powder, and hurl upward of 30 tons of projectiles, at a cost of about $6,320.

The cost of the gun, exclusive of carriage and the machinery for working it, was estimated at £15,000, and the factory-plant and experi mental trials at £10,000. The actual cost of each of the eight guns be best known when all are manufactured.

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