The Works Of Messrs. Schneider And Co.

XXXVIL COAST-DEFENCE GUNS. A CERTAIN number of types of Schneider-Canet naval guns described in preceding sections, possess details in common with the artillery specially designed for coast defence ; such details are, however, more or less inodified in some of the latter guns, in order to meet the particular requirements they have to fulfil. As regards, foi’ instance, mountings for quick-firing guns of equal calibre, those for coast defence frequently differ from those for naval guns, in the arrangements provided for giving the former a greater range of elevation. To obtain this, the bedplate is fitted to a special platform, or to a masonry foundation, thus insuring the required height of soleplate for coast-defence batteries. Notwithstanding the faet that both these types of quick-firing ordnance are very sitnilar, we shall describe some examples of coast- defence guns, in order to point out their special charac- teristics. The ordinary dass of non-quick-firing material, which is still used for the armainent of coast-defence batteries, includes all the series of large-calibre guns of medium lengths which are derived from the older non-quick-firing types, but are improved. Such a matériel is quite in the right place in coast defences, for it constitutes a powerful armament, and does not require, in time of peace, a numerous personnel for maintenance. All the parts are of very simple construction, désignée! so as not to be affeeted by variations in temperature. In action these guns can be worked by untrained men, and the careful drilling of the personnel is not difficult, and does not take up mueh time. In order to fulfil the varions requirements of this particular service, the Schneider-Canet coast- defence armament includes guns, howitzers, and mortars. 27-Centimetre (10.630-In.) 28-Calibre Coast Defence Gun (Fig. 855).—A large number of guns of this type have been built, especially for the Japanese Government. Weight of gun 25,890 kg. 57,060 Ib. ,, mounting... 35,720 kg. 78,727 11>. ,, projectile ... Elevation 21(5 kg. 476 Ib. + 20 deg. + 20 deg. - 20 deg. - 20 deg. Training Muzzle Velocity with prismatic brown 270 deg. 270 deg. powder 570 in. 1870 ft. The gun is built throughout of steel ; it consists of a thick tube which runs the whole length of the gun, and is strengthened by sets of coils. It is provided with a two-motion breech-block, of the type described in a preceding: section dealing- with large-calibre breecb-blocks ; 10 O o friction fuses are used foi' firing, obturation being insured by a special steel cup. The mounting consists of three main parts, the bedplate fixed to the platform, the slide, and the gun-carriage. The bedplate acts as a fixed support for the movable slide, the latter revolves round its vertical axis on coned rollers. The lower part of tlie bedplate is made with a horizontal ring, which forms a roller-path, and is strengthened by ribs where required ; the upper part contains a vertical cylinder, which fits in a corresponding one on the slide, and forms a pivot for lateral training. The slide is made with two vertical cheeks on the top, part of which bear the carriage slide shoes ; the cheeks are strengthened by ribs, and are joined together at their lower part by a domed cap cast in one piece with them ; inside the cap is a vertical cylinder which complétés the pivot above referred to. A horizontal ring, formed by the bending up of the lower edge of the dorne, acts as a bearing surface for the slide on the rollers. The slide contains the elevating- mechanism, with a platform for the gunner, the lateral training mechanism, and the charging cradle with its platform. In order to facilitate the riinning out of the gun without inereasing the angle of incline of the slides, cylindrical rollers are provided, the top part of which project slightly above the surface of the slides ; the carriage, therefore, rolis on the slides during reeoil and running out. The cheeks are made in front with an excess of metal, for holding the reeoil cylinder piston. When the carriage runs out, the buffers bear on the front stay of the slide, thus preventing a too suclden stoppage. Four damps at the lower part of the slide hold the lower edge of the bedplate, and set up to offer together a large vertical résistance during fire ; at the same time the arrangement provides for the necessary angular displacement for lateral training. The mechanism for elevating the gun is placed in a ehest on the right cheek, and works in the following manner : The gun is provided with a toothed sector, on which acts a pinion keyed on a shaft, the latter being also fitted with a hélicoïdal wheel worked by an endless screw. The crank acts on a pair of bevel wheels, one of which is on the endless screw shaft. The platform for the gunner is 011 the right cheek. Lateral training is obtained by a chain placed in a recess round the circumferenee of the bedplate. It is guideel by two friction rollers, and passes on a grooved pulley cast in one piece with a hélicoïdal wheel ; the latter is worked by an endless screw. The endless screw is keyed on a shaft provided at both ends