Page:The American Cyclopædia (1879) Volume I.djvu/832

 796 ARTILLERY his biff-grained powder, obviated the mam difficulties in making very large cast c a non, a 15-inch gun weighing 60,000 Ibs. was successfully cast in 1860, followed in 1863 by a 20-inch gun weighing 115,000 Ibs. and firing a 1 080-lb solid shot. The Rodman smooth-bores are the 20, 15, 18, 10, and 8-inch, the last two bein<* but temporarily retained in service until replaced by heavier guns ; only two 20 and two 13-inch guns have been made for experimental purposes, but they have given favorable results. A large number of 15-inch Rodmans are now in service ; the shell weighs 330 Ibs., the solid shot from 440 to 425 Ibs., the service charge being 100 Ibs., which will give an initial ve- locity of 1,500 feet. The accuracy of the gun at 1,500 yards is as great as that of any rifle ; its trajectory within this distance is flatter, and the projectile being round has greater precision in ricochet fire. On the other hand, rifles can project loaded shells of peculiar construction so as to penetrate and then explode in the ob- ject ; their projectiles do not lose their velocity as soon as those of smooth-bores, so that they are more effective at long ranges; while if made of wrought iron or steel, though far more costly, they have much greater endurance than cast-iron guns. The experimental Rodman cast- iron rifles, 12 and 8-inch, the former having the exterior form of the 15-inch smooth-bore, were found not to possess the requisite strength, and the United States is now (1873) about to ex- periment upon several other systems of rifled cannon, with a view to the adoption of that found most advantageous. The 20, 15, and 18- inch, and of late the 11-inch, naval guns have the Dahlgren exterior shape, but are cast hol- low with the Rodman elliptical chamber. A 3-inch rifle muzzle-loading wrought-iron gun was adopted in 18lil ; it is made by wrapping boiler plate about an iron bar so as to form a cylindrical mass, which is brought to a welding heat in a furnace, and then passed between roll- ers to thoroughly unite it ; the trunnions are afterward welded on and the piece bored and turned to the proper size and shape, the latter being of the general character of the Rodman pattern. Its weight is 820 Ibs., that of the projectile being only 10 Ibs., in which respect it does not compare favorably with the Prus- sian, Russian, and Austrian fours, which fire a much heavier projectile in proportion to the weight of the piece. The 4-inch rifle is simi- lar in shape to the 3-inch, and was adopted about the same time : it is of cast iron cooled from the exterior, its weight being 3,450 Ibs., that of the projectile 30 Ibs., while the Russian nine, which only weighs 1,382 Ibs., fires a 31- Ib. projectile. Though intended for siege and garrison purposes, it has been used with an army in the field in spite of its want of mobility. The Parrott muzzle-loading rifles are cast-iron pieces of ordinary dimensions, strengthened by shrink- ing a wrought-iron hoop or barrel over that pqrtion of the reenforce which surrounds the charge ; the cast-iron body in the larger cali- bres is hollow-cast on the Rodman plan ; the barrel is shrunk on by the aid of heat, the cast iron being prevented from expanding by a stream of cold water made to run through the bore. Parrott guns consist of 300, 200, 100. 30, 20, and 10-pdrs., the diameter of the bores being respectively 10, 8, 6'4, 4'2, 3-67, and 3 inches, and weights of projectiles 250, 150, 86, 28, 19, and 10 Ibs. This system has not been adopted by the United States government, though a great many Parrott rjfles were used during the civil war, and a certain number of guns of the larger calibres are still temporarily retained. While some Parrott cannon have shown very great endurance and been largely used in breaching masonry and other siege operations, a number have burst, particularly in the navy, the accidents being mainly ascribed to the breaking and wedging of the projectile in the bore ; the inventor, however, now as- serts that he has corrected this evil. At the beginning of the war a number of old 42 and 32-pdrs. were rifled on the Parrott system for temporary use, and served with projectiles of FIG. 18. Parrott Gun. twice the weight of the corresponding round shot ; the 42-pdrs. only were hooped. The Brooke gun, made and used by the confede- rates, is very similar to the Parrott in shape and construction, except that the hoop is made of wrought-iron rings not welded together. King's counterpoise gun carriage, recently tried in the United States, was found to excel Mon- crieff' s in strength and simplicity, while giving equal protection to the piece and cannoneers. The counterpoise, connected with the top car- riage by ropes and pulleys, is placed in a well made in the parapet opposite the gun; the chassis slopes considerably to the rear, so as to form an inclined plane for the descent of the piece and top carriage ; as the recoil forces them back and down, the counterpoise rises in the well until its weight suffices to bring the piece to rest behind the parapet. The counterpoise being heavier than the gun, the cannoneers havo no difficulty in making it run up into battery after throwing the eccentric wheels into gear. An improved form of the ribaudequin or organ gun of the 15th century, temporarily in the United States service, received favorable men- tion at the siege of Charleston in 1863, under the name of the Requa rifle battery ; it con- sisted of 25 horizontal barrels in an iron frame,