PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 



425 



HOW TO MAKE PROJECTILES. 



A variety of new forms of projectiles are required for 

 these guns, as the necessity for large guns comes from 

 the important changes in the mode of constructing ships 

 of war covered with iron armor, and the projectiles for 

 attacking these, successfully, must be the same, whether 

 the enemy were opposed bj^ our guns on ships or fortifi- 

 cations. Those here represented are solid shot and shell, 

 14 inches in diameter, and 28 inches in length. All these 

 projectiles, it will be noticed, have their greatest dis- 

 placement (as they are projected through the air) at their 

 rear end. But their center of gravity is forward of their 

 center of form. A shot fired from a rifled gun at high 

 elevation, is inclined to keep the same direction or angle 

 of its axis, about which it revolves, and during the last 

 half of the trajectoiy this direction comes to be nearly 

 a right angle to the direction of its flight. The resist- 



ance to its forward nrotion is as its displacement of air. If its greatest dis- 

 placement be aft, the resistance of the air (when the projec- 

 tile is moving in the direction of the parallel lines) against 

 its sides, inclines to bring the rear end of the shot back- 

 ward, so that its axis coincides with the line of flight. The 

 center of gravity being forward of the center of form, would 

 assist in depressing the forward end of the shot, as the line 

 of the trajectory was depressed. The figures show a longi- 

 tudinal section, and a rear view of one form of my inven- 

 l|l>tion, which has the required qualities to an eminent degree, r 

 and is thus adapted to the penetration of iron armor plates- 

 at a long range with a high trajectory', striking point foremost. 



The main body A, of the projectile, is of cast iron; the 

 ring B is of steel, hardened. The front of the projectile is 

 concave. The screw bolt C, is of iron, and merely fills a 

 hole which is made by a suitable core in casting, to secure 

 more uniformity in the metal while cooling. The rear 

 portion is provided with projections D, adapted to correspond 

 with, and fill as closely as desirable, the rifle grooves of the gun ; and the 

 or ward portion is provided with three boutons or projections E, which may 



