VELOCITY. 307 



sideways of an elongated ball, and it is this accident which 

 forms the chief impediment to rifle shooting. The impetus 

 being given to the hind end of the ball, while the resistance 

 of the air is offered on the front, there is a constant tendency 

 to the one overtaking the other, in doing which the ball 

 must necessarily offer its side to the point at which it is 

 aimed. The greater the spin the more this tendency is 

 checked, for no sooner does the base begin to turn over to 

 the right, than it is forced round to the left, and so on in 

 succession to every point in the circle of which its line of 

 flight is the centre. 



VELOCITY GREATEST AT THE MOMENT OP LEAVING 

 THE MUZZLE. 



It has been found by experiment that a ball will pierce 

 certain substances at 100 or 200 yards, which it would fail 

 to do at half or a quarter the distance; and upon this fact 

 a theory has been propounded which is adverse to a funda- 

 mental law of nature. This theory is, that when the 

 resistance offered by the friction against the sides of the 

 barrel is taken away, the impetus given by the explosion is 

 allowed its full scope, and the ball increases in velocity up 

 to a given point. In fact, it is said that the ball vires 

 acquirit eundo; but Mr. Boucher, in a letter to The Field, 

 completely disposes of this fallacious theory by the following 

 experiment, which I insert as detailed by him. 



" Again : with regard to the penetration of shot being, at 

 all ranges, a test of its velocity, the correct interpretation of 

 the law of action and reaction seems, in this case also, to be 

 sadly overlooked and disregarded. I send you six bullets, 

 taken from hundreds of a similar description. See fig. 65. 

 Those marked a and d were fired at 40 yards' distance, and 

 penetrated about one foot ; b and e were fired at 100 yards, 

 and penetrated about two feet ; while c and f were fired at 

 200 yards, and penetrated nearly three feet and a half. Now, 

 sir, I have been coolly told in the columns of your paper (March 

 20) that * I am neither a profound thinker nor a careful ex- 

 perimentalist, or I must know the incontrovertible fact that 

 a bullet does gain in speed after leaving the muzzle of the 



