Guns and Projectiles. 115 



of initial error, it would suffer furtlier equally unknown and 

 unknowable deflections as it went along. Its centre of gravity 

 might not have been co-incident with the centre of its sphere ; 

 and if it were so when it entered the barrel, the shape 

 was sure to suffer from the explosion, so as to throw it out. 

 There were also more refined reasons why a round ball could 

 not be depended upon to move in one plane during any con- 

 siderable flight. 



In the early rifles the ball was driven into the barrel so as 

 to fit tight, and one source of error was thus removed. More- 

 over, it was found that the grooving of the rifles could be made 

 to spin the ball about an axis parallel to the sides of the barrel 

 and coinciding with the plane of its intended flight. Under 

 these circumstances, and by avoiding crushing the ball out of 

 shape in the process of loading, very fair shooting could be 

 accomplished at from fifty to a hundred yards, and moderately 

 bad shooting at twice that distance. During the continental 

 war it was a great achievement if anybody was made unsafe by 

 rifles at four hundred yards, and the artillery was proportionably 

 ineffective as a destructive weapon. 



Among the earliest people to introduce greater precision 

 into their arms were the Americans and the Swiss, both of 

 whom, adopted principles pointed out by Eobins, the mathe- 

 matician, and even by Newton. Without giving them exclusive 

 credit, they practically demonstrated that projectiles must not 

 be round, if the best effect was to be obtained. A round ball 

 is easily started with a high velocity, but the surface of resist- 

 ance it opposes to the air is so great in proportion to its moving 

 power* that it soon takes to a slow trot, and then comes to- 

 rest. If three or four balls be placed one behind the other, it 

 will be seen that so long as they touched each other, and 

 moved straight forward, the front one would clear the way, and 

 the others would pass with comparatively little opposition. 

 This is, in popular language, the philosophy of elongated pro- 

 jectiles ; but to enable them to act well they must always 

 move in one plane. As long as they go face foremost, they 

 have, as compared with a round ball, the advantage (supposing 

 the velocity to be the same) of the additional momentum due 

 to their greater weight, while their ai*ea of resistance is not 

 proportionably increased. 



The mechanical problem which the improvers of the rifle had 

 to solve, was to obtain the best form of elongated projectile, and 

 prevent its turning over or going side foremost in its flight. 

 It was soon found that a long conical projectile could bo made 

 to movo with its smallest and lightest end foremost for many 



* The momentum of a projectile is equal to its weight multiplied by its 

 velocity. 



VOL. V. — NO. If. K 



