COAST ARTILLERY, or FORTRESS ARTIL LERY. Under this head are included the heavier guns and mortars, which are used for the arma ment of permanent works, usually on the sea coast, and which are mounted on carriages not intended for transporting the guns, but only as supports from which they are to be fired. These carriages are designed so that the guns may be pointed in any direction at various angles of ele vation and depression. They arc classified as barbette, casemate. and flank defense, according to their use, and into front pintle (the pintle be ing the pivot or bearing containing the axis of ro tation) and centre pintle according to the manner of traversing. Barbette carriages are intended to be fired over an open parapet. and are of two forms—fixed and disappearing. Disappearing carriages are hidden behind the parapet except when firing. They are of two classes—disappear ing ea rriages proper and the gun-lift carriages. Casemate carriages are those mounted in a cov ered emplacement and fired through an em brasure (q.r.).
The modern seacoast cannon in the United States service are the 8, 10, and 12-inch breech loading rifles and the 12-inch breech-loading mortar. In addition there is a 12 cm. (4.7 inch) rapid-fire gun, using a projectile weighing 45 pounds propelled by smokeless powder. The 8 inch rifle weighs 32,430 pounds and fires a 300-pound projectile with a charge of 125 pounds of powder. The 10-inch rifle weighs 67,200 pounds and fires a 575-pound projectile with 250 pounds of powder. The 12-in•h rifle weighs 128, 719 potun6 and fires a 1000-pound projectile with 487 pounds of powder. These guns are mounted on barbette carriages. The barbette carriages are non-disappearing and disappearing. The 12-inch breech-loading rifled mortar weighs 29,000 pounds and fires a 1000-pound projectile with 105 pounds of powder. The illustration shows in detail a typical gun and mortar for coast defense as used in the United States service. Other illustrations, including one of a United States disappearing gun, will be found in the article ORDNANCE.
The 16-inch breech-loading rifle of the United States system is one of the largest guns ever constructed. The Italian 17.7-ineh, the French 16.5-ineb, and the Armstrong 16.25-ineh guns,
do not compare in point of energy and range with the recent American gun. With smokeless powder the gun requires a charge of 576 pounds (of the old black powder 1176 pounds would be needed) and fires a projectile 5 feet 4 inches long, weighing 2400 pounds, with a muzzle velocity of 2300 feet per second, developing a muzzle energy of 88,000 foot-tons, which gives a penetration of 42.3 inches of steel at the muzzle. These figures will be considerably inereased when a suitable slow-burning powder is secured, but even now the gun shows an enormous superiority to any of the large guns mentioned above. The Italian gull, for instance, with a projectile weigh ing 2000 pounds and a muzzle velocity of 1700 foot-seconds (feet per second). develops only 40,000 foot-toils muzzle energy, not half that of the American gun. The French gun projectile weighs 1700 pounds, and with 1700 foot-seconds muzzle velocity, develops a maximum muzzle energy of only 36,000 foot-tons, while the Eng lish gun projectile of 1800 pounds, with a muzzle velocity of 2100 foot-seconds, gives a muzzle energy of 51,000 foot-tens. It is seen, therefore, that the maximum energy of the Italian gull is 45 per cent., that of the French gun 41 per cent., and that of the English gun 65 per cent. that of the United States gun. The maximum range of this enormous gull is 20.973 miles, the projectile reaching a height of 30,516 feet in this flight. The total length of the gun is 49 feet 2.9 inches; its weight about 130 tons.
England uses both breech and muzzle-loading cannon in her coast defense. Her largest guns are the four 100-ton guns at Malta and Gib raltar. Probably the most powerful gun in the English system is the wire-wound 12-inch breech loading rifle, Mark VIII., which is 37 feet 1 inch long, weighs 46 tons, and fires an 850-pound projectile, with a muzzle velocity of 2367 foot seconds. The coast artillery guns are the rifled muzzle-loading 64-pounders, SO-pounders, 7, 9, 10, 10.4, 11, 12, 12.5, 16, and 17.72 inch guns. The breech-loading, 4, 5, 6, 8, 9.2, 10, 13.5 inch and 32-pounder smooth bore. In all, England has 920 guns of various types mounted in her seacoast forts.