ORDNANCE. 



733 



pieces, usually of small caliber. There had 

 been for some years before the public, several 

 inventions for the purpose of applying the prin- 

 ciple of rifling, which had been so successful in 

 small arms, to cannon, but none of these had 

 been adopted by the Government, or were in 

 use in the field batteries or forts under the con- 

 trol of the War Department, or in the vessels 

 of the navy. The adaptation of the system of 

 rifling invented by Charles T. James for small 

 arms, was proposed, and repeated experiments 

 were made with it, but it was found to require 

 material modifications, and the death of the in- 

 ventor by the explosion of his own cannon, in 

 October, 1862, caused the abandonment of the 

 efforts at improvement of that gun. Capt. K. 

 P. Parrott, of the West Point foundry, had in- 

 vented just previous to the war, a rifled can- 

 non, which, with some improvements in the 

 projectiles and the method of rifling, has proved 

 the most successful of the numerous attempts 

 at producing rifled cannon in this country. It 

 is a muzzle loader (the breech-loading cannon 

 having proved objectionable), and consists of a 

 cast-iron gun, much lighter than ordinary, but 

 having a " reinforce " or cylindrical jacket of 

 wrought iron shrunk around the breech at the 

 seat of the charge. His method of shrinking 

 this cylinder on the cast-iron gun is peculiar. 

 The gun is laid nearly horizontally with its 

 axis, the muzzle being slightly depressed, and 

 when the cylinder is heated and slipped on, a 

 stream of cold water is forced continuously into 

 the bore of the gun, and from its slight depres- 

 sion flows out constantly. By this means the 

 inner surface of the cylinder is cooled soonest, 

 and contracts closely on the gun, drawing the 

 outer surface around it. Six calibers of these 

 guns are made by order of the Government, viz. : 

 10, 20, 30, 100, 200, and 300 pounders. The 

 following table gives the diameters and length 

 of bore, the weight and relative caliber, of each 

 of the smooth bores : 



"We give below the ranges of each of the first 

 four sizes at different elevations. 



TEN-POUNDER GUN, BORE 2.9 INCHES. 



Ranges with charge of one Ib. of mortar powder. 





Mortar powder should always be used with 

 this and the next two sizes. 



TWENTY-POUNDER GUN. BOBB, 8.67 INCHES. 



Ranges with charge of two lb. of mortar powder. 



THIBTY-POTTNDBR SIEOE GUN. BORE, 4.2 INCHES. 



Ranges with 3% Iba. mortar powder. 



ONE HUNDRED-POUNDER GUN. BORE, 6.40 INCHES. 



Charge, ten Ibs. ; number 7 powder. 



The charge for the 8-inch or 200-pounder 

 gun, is 16 Ibs. The projectiles weigh about 

 150 Ibs., and the ranges as ascertained in the 

 siege of Charleston, are somewhat greater than 

 those of the 100-pounder. At the greatest ele- 

 vation the range attained exceeded five miles. 

 The 300-pounder weighs 26,000 Ibs., uses a 

 charge of 25 Ibs., and a projectile weighing 

 250 Ibs. At an elevation of 35 it has thrown 

 this formidable missile over five and one fourth 

 miles. 



The Parrott projectile was designed expressly 

 for the gun. The groove, the twist, the caliber, 

 and the heavy charge for each caliber, are all 

 founded upon the proper adaptation of the pro- 

 jectile to the gun. The length of the shell is 

 equal to three calibers, and is cylindro-conical 

 in form. A brass ring is fitted around the 

 contraction of the base, making it cylindrical. 

 The gas entering between the iron and the 

 brass, forces the latter into the groove, by 

 which the rotary motion is communicated to 

 the projectile. The ring is prevented from 

 slipping oif the shell by having the two sur- 

 faces in contact corrugated, and by some pro- 

 jections on the upper edge of the ring, which 

 are jagged into the metal of the shell. Great 

 simplicity, accuracy, and strength are the 

 crowning merits of this gun. 



