Armistead, Walter

KEITH, an American general, born in Va., in 1780, graduated at West Point, became chief engineer in the war against England in 1812-13, and commanded the army sent out against the Indians in Florida, 1836-37. Died in 1845. Armor Plate. The word armor, in recent times, has come into use in a new significance, it being applied to an iron or steel covering for ships and fortifications as a protection against cannon projectiles. The idea of protecting ships in this manner originated with American engineers-particularly with Robert Stevens, of Hoboken, N. J., who in 1842 presented to the Government plans for an armored ve el having a sloping battery protected by iron. His plans were accepted, and in 1844 the keel of the famous Stevens battery was laid. The next step was taken in 1854, when the French and English began to construct iron-clad naval batteries, covered with 4 and 4%-in. iron respectively. In the following year the French batteries, the first finished, silenced the Ru ian forts at Kinburn, in the Crimea. In 1860 the French ship La Gloire was covered with iron plates of 41⁄2 in. thickne , a protection which proved superior to the attack of the smooth-bore 68pounder, then the most powerful naval gun in use. In 1862 took place the first contest between armored ve els, in the famous combat in Hampton Roads between the Monitor and the Merrimac . In the former of these the revolving turret system was first introduced; the latter was a naval battery, with sloping, iron-clad roof. The result of this battle proved conclusively that the day of wooden war ve els was at an end; and, during the remainder of the American Civil War, a number of ironclad monitors, gun-boats, and floating batteries were brought into active service. This practical demonstration was followed by a period of inactivity on the part of the U. S. Government, but of active operations in iron-clad construction by Great Britain and other European powers, with the result of an enormous advance in the resisting power of ships and a correlative advance in the penetrating power of guns. The 472-in. plates of 1860 soon proved usele against the powerful rified guns later brought to bear upon them, and a contest between the penetrative power of projectiles and the resistance of armor began, which has continued up to the present time. In 1867-the heaviest reliable plate that could then be made being 6 or 7 inches-a system was adopted of superposing several thick plates. By 1872 it had become po ible to produce 12-in. plate of good quality, but by this time the power of guns a 4-in. solid plate, readily pa ed through 6 in. of 1-in. plates laid together. In 1876 the Italian government, having resolved to build iron-clads surpa ing any previously produced, called for a competitive test of 22-in. plates of various materials. The result was instructive, proving that solid steel plates alone was capable of resisting the force of impact from the 100-ton rifled Armstrong gun then in use. Plates of this kind, though wrecked, kept out all shot, while the iron targets were pierced. The result of this trial practically put an end to the use of wrought-iron armor, steel taking its place in subsequent operations. Compound plates (consisting of wrought iron with a steel face), were manufactured in at short range succe ively by a 10-in., 12-in. and 13-in, gun. The 10-in. gun, with a 500-lb. shell and a striking velocity of 1,856 feet per second, caused a penetration of 11 inches, but no cracks were developed and the backing remained sound. The 850-lb. projectile of the 12-in, gun, with a velocity of 1,800 feet per second, was destroyed after it had penetrated 17 inches; the plate was cracked but the backing held firm. The great 13-in. gun, with a striking velocity of 1,800 feet and energy of 24,736 foot pounds, sent its 1,100-lb. shell through the entire target and two 16-in. oak timbers, after which the shell buried itself 12 feet in the sand. The resistance to 4 shots of such energy and striking within so limited a space, shows IMG:content-0470.png:[graphic][merged small] IMG:content-0471.png:[graphic] had so increased that even this thickne would be pierced by projectiles, and new progre in armor plating became nece ary. The British ship Dreadnaught had her turrets covered with two 7-in. plates, separated by 9 in. of teak, and backed by 6 in. of teak and two 34-in. skin-plates. But the rifled gun soon gained the supremacy over this weight of armor, and the Inflexible was covered with two layers of 12-in. plate, separated by 11 in. of teak and backed by 6 in. of teak and two 1-in. skin-plates. Continued tests, however, have rendered it evident that armor made up of several superposed thin plates has much le resisting power than solid plates of the same thickne , and the latter only is now used. Thus a 60-lb. round shot that failed to penetrate IMG:content-0472.jpg:[graphic][subsumed][subsumed][subsumed] IMG:content-0473.jpg:[graphic][subsumed][subsumed] of the striking projectile was very much weakened. As only long cannon for direct fire can be employed in such revolving turrets and batteries, cupolas for howitzers and mortars have to be differently arranged. These weapons being always fired at the same angle, the cupola which turns in the circular glacis can be quite flat, and, on account of its light weight, be rigidly connected with the carriage, which revolves on a central pivot. For the shorter mortars the cupola is contracted to a sphere inclosing the mortar, so that only a small portion of the cupola about the opening extends from the glacis. The revolving turret was succeeded by the introduction of disappearing turrets for small and medium-sized guns, these yielding greater safety than those which simply revolved to turn their portholes away from the enemy. Subsequently, disappearing turrets for heavier guns were built in France by Galopin. In these the moving part, cylindrical in shape and covered with a slightly arched hood, has a sinking as well as a turning motion, and can be lowered until its top is on a level with the glacis, so that when loading there is no opening exposed to the enemy and the tur IMG:content-0474.png:[graphic] ret itself is scarcely visible. In many cases, especially in vast fortifications, overhead covering to the fort is not deemed nece ary; and in these the barbette turret, in which the guns fire over a stationary ring of armor, or the disappearing carriage (designed by Moncreiff and completed by Armstrong and others) has been adopted. In the former the gunners are protected by a shield connected with the carriage mounted on a turntable. In the disappearing carriage the gun also stands on a turntable in a basin of masonry or armor, which is provided with a perfectly flat, armored top, which cannot be seen from a distance. When such an invisible turret is brought into action, the barrel of the gun is raised by a pneumatic device, and appears at an aperture in the roof, which is opened at the proper time; and after firing the gun is returned automatically, by recoil, to the protected loading position. Armored fortre es now exist on the coasts of all maritime civilized countries, the chilled iron turrets being preferred in Germany and Italy, the disappearing carriage in England and the United States. Immense inland fortre es exist in Roumania, on the Ru ian frontier, and armored fortifications are found inland in many other countries, as on the eastern frontier of France. As will be seen, the development of projectile power has made armor more and more indispensable, the competition between shot and armor being no longer a feature of naval warfare only, but of war on land as well.