Page:EB1911 - Volume 20.djvu/256

Rh The French 10·7&#8202;″ Howitzer.—As a typical piece the 10·7″ howitzer may be taken, which the French transported by special horse draught, as it was found too heavy for the type of siege railway made use of at the mock siege of Langres in 1907. Its total equipment weighs 22 tons and it is transported in four components, namely, the piece, the carriage, the slide and the platform. A battery of six pieces would thus require, exclusive of ammunition transport, 24 vehicles that would weigh 130 tons. The howitzer was designed originally for coast defence; it weighs about 5 tons and its bed weighed 6 tons: to this equipment was added a slide and a platform, consisting of a thick plate of iron upon which the slide moves. The platform is provided with a pivot upon which the front part of the slide fits. The latter consists of an iron framework, having lateral movement around the aforesaid pivot; its rear portion is provided with rollers to facilitate its movement on the platform. Its upper portion consists of two inclined rails along which the bed or carriage of the howitzer slides. To check recoil a

hydraulic buffer is attached to the front of the slide and also to the bed. The fighting units of siege artillery in the British service are companies and brigades; each company would be armed with from 4 to 6 light siege pieces or from 2 to 4 heavy pieces. A company is usually a major’s command. Three such companies would form a siege brigade under a lieutenant-colonel. If a siege train of any magnitude were organized it might be necessary to combine two or more brigades into a division under a colonel or brigadier. In the French service each siege train consists of three divisions. A division is divided into groups and comprises some 50 pieces of ordnance, heavy and light.

The armament of modern coast fronts consists of (a) heavy B.L. guns, 9″ and upwards; (b) medium guns, 4″ and upwards, and (c) light Q.F. guns; all these being for direct fire; and (d) guns, howitzers or mortars of various calibres for high angle fire. Typical guns of type (a) are the Krupp 12″ gun and the British 9·2 B.L. gun. The Krupp 12″ gun is built up of crucible cast nickel steel, not wire wound. It is 45 calibres long and has the Krupp wedge-shaped breech-closing apparatus. It is fitted with a repeating trip lock. The cartridge is a metallic case containing a charge of 290 ℔ of tubular powder. The projectiles are of two weights, 770 ℔ and 980 ℔, and the respective muzzle velocities are 3025 f.s. and 2700 f.s. The British 9·2 B.L. gun is of wire-wound construction and is over 48 calibres long. It has the asbestos pad and Welin screw system of obturation, and its charge of 103 ℔ of cordite, contained in a cartridge of silk cloth, fires a 380 ℔ projectile with a muzzle velocity of 2643 f.s. A typical gun of class (b) is the British 6″ mark VII. It is similar in construction and breech mechanism to the last-named and fires a 100 ℔ projectile with a charge of 23 ℔ cordite, giving a muzzle velocity of 2493 f.s. A typical gun of class (c) is the British 12 pr. Q.F.; its weight is 12cwt., it is made of steel, is 10·3 calibres long, and with a cordite charge of 1 ℔ 15 oz. it fires a projectile 12 ℔ in weight with a muzzle velocity of 2197 f.s. and a possible rate of 15 aimed rounds a minute. A typical piece of class (d) is the 11″ Krupp howitzer. It is 12 calibres long, has a charge of 28 ℔ smokeless powder and fires steel shell weighing 470 ℔ or 760 ℔. It is provided with a shrapnel shell of the former weight which contains 1880 bullets.

The methods of mounting of coast ordnance are many; space only permits of referring to certain typical arrangements.

1. The Moncrieff Principle.—The disappearing carriage originated, at all events in England, with Colonel Sir A. Moncrieff, who, about 1864, proposed to utilize the energy of recoil to bring a gun into a protected position and at the same time to store up sufficient energy to raise it to a firing position when loading was completed. To effect this a heavy counterweight

was so adjusted that its tendency was to raise the gun; when the latter was fired, it raised the counterweight and a ratchet and pawl followed the action up: when the pawl was released the counterweight brought the gun back to the firing position; this application of the principle had many drawbacks, and never had any success with guns over 7 tons in weight. It was not until Moncrieff invented the hydropneumatic appliances that any real progress was made. In 1888 was introduced into the British service the first of a large group of disappearing mountings for guns of types (a) and (b). where the energy of recoil was absorbed chiefly by forcing a large volume of liquid through a narrow opening or recoil valve, and also by further compressing a large volume of already highly compressed air; when recoil was completed the recoil valve closed and the air was retained at very high pressure: the energy thus stored up returned the gun to the firing position. The action will be understood from the following example.

The British 6&#8202;″ B.L. Gun on H.P. Mounting, Mark IV.—Fig. 78 shows a general view of the mounting; fig. 79 is a vertical and