VARIETIES OF BALLS. 



325 



)ase of the ball at b. This kind of rifle is also used by Mr. 

 Whit worth with the ordinary Pritchett ball. 



POLYGROOVED RIFLES. 



Lastly, we must include all the polygrooved plans which 

 have been tried from time to time, and which have varied 

 from seven to such a number as to be almost beyond enumer- 

 ation, and looking as fine as horsehair to the eye. These 

 are, however, rarely used in the present day, Mr. Westley 

 Kichards' new rifle being an exception to the general rule. 

 See figs. 86 and 87. 



VARIETIES OF BALLS. 



But besides these varieties in the rifling, there are also 

 several different kinds of ball applicable to most of them. 

 Originally all bullets were spherical, next to which came the 

 sphere with a band, and afterwards two bands upon it. It 

 then became egg-shaped, after Robins' s suggestions, in order 

 to obtain the centre of gravity well forward. Then came the 

 variously-shaped cannelures or indentations round the base of 

 the ball, which were first introduced with the object of re- 

 tarding the flight of the hindmost part; but this being better 

 attained by accelerating the speed of the foremost end, they 

 were abandoned for that purpose, and are only now used as 

 receptacles for grease. In 1836, Mr. Greener invented a 

 ball and plug, which he then described as follows: "An 

 oval ball, with a flat end and a perforation extending nearly 

 through it, is cast, a taper 

 plug with a head like a 

 round-topped button is also 

 cast, of a composition of 

 lead, tin, and zinc, as shown 

 in fig. 76 a and b. The end 

 of the plug being slightly 

 inserted into the perfora- 

 tion, the ball is put into 



the rifle or musket with either end foremost. When 

 the explosion takes place, the plug is driven home into the 



GREENER'S BULLLT. 



