28 



Scientific Proceedings, Royal Dublin Society. 



justified in accepting the mean velocity in the range of 120 feet to 

 be the actual velocity at 60 feet from muzizle. • 



Velocities at 60 feet from Muzzle of various. Charges of Shot, 

 observed May Qth and 12th, 1879. 



[The figures are tlie averages of four shots in each case.] 



From these velocities can be calculated by Bashforth's Tables 

 what are the muzzle velocities and the final velocities at 120 feet, 

 180 feet, &c. For this purpose, however, it is necessary to deter- 

 mine the diameter and weight of the individual pellet whose move- 

 ment one wishes to examine, and also to assume that on leaving the 

 muzzle it is circumstanced, as to the resistance of the air, as if it 

 were the only one in the charge, and also spherical. In practice 

 the resistance to each pellet near the muzzle is modified by the 

 contiguity of others, whereby the sum of all the resistances is re- 

 duced; but as want of true sphericity would increase, the effect of 



