192 ELEMENTARY PRINCIPLES OP GUNNERY. 



first movement. At this instant the action of the powder is 

 comparatively slight, so is the reaction by friction, &c., and 

 so is also the force of the recoil ; for the action of the charge 

 in passing through the last three quarters of the barrel over- 

 coming friction and other causes of retardation is the great 

 cause of the recoil which is felt, unless, indeed, the charge is 

 improperly jammed down when loading. This may be proved 

 by cutting off three-fourths of the barrel and firing the same 

 quantity of powder and shot from a recoil-rest. It would 

 then be seen that it is not the original repulsion which caused 

 the motion that man uses as his servant, but the momentum 

 gradually accumulated by such free and unopposed repulsion, 

 and the progressive, though rapid, ignition of all the particles 

 of the powder. 



" Of friction there are two kinds. The first is denominated 

 sliding, and the second rolling friction. They are governed 

 by the same laws, though the former is much greater in 

 amount than the latter, under given circumstances. A round 

 ball fired from a smooth bore will leave the muzzle with 

 greater velocity than an elongated bullet fired from a rifle 

 the calibre of both and the charge of powder being the same 

 but the recoil of the smooth-bore gun will be less than 

 that of the rifle, simply because a very small proportion of 

 the surface of the round ball, which has a rolling motion, 

 can ever come in contact at the same time with the sides of 

 the barrel. There is, therefore, less friction, and, conse- 

 quently, less retardation to the accumulating speed of the 

 round ball before it reaches the muzzle : still action and 

 reaction will be equal, as the extra force which the bullet 

 carries with it, after leaving the muzzle, is just so much force 

 deducted or taken from the friction and recoil the first being 

 the cause of the greater effect in the second. This is easily 

 proved by firing both bullets through a revolving meter from 

 a recoil-rest. It maybe added, however, that, if both bullets 

 were fired at the same instant, at the same elevation, the 

 elongated bullet would soon overtake the round one and pass 

 it, as the latter, being lighter, would sooner be retarded by the 

 friction and resistance of the external air. This may also be 

 easily proved by noting the degrees of elevation necessary to 

 make both bullets range the same distance. 



