Experiments upon Giinpowder. 75 



a supposition that the action of the elastic fluid gener- 

 ated from the powder, is always the same in any and 

 every given part of the bore, when the charge is the 

 same, whatever may be the weight of the bullet, and as 

 no allowance is made for the expenditure of force re- 

 quired to put the fluid itself in motion or for the loss of 

 it by the vent, it is plain that the theory is defective. It 

 is true, Dr. Hutton in his experiments found this law 

 to obtain without any great error, and possibly it may 

 hold good with sufficient accuracy in many cases ; for it 

 sometimes happens that a number of errors, or actions, 

 whose operations have contrary tendencies, so compen- 

 sate each other that their effects, when united, are not 

 sensible. But when this is the case, if any one of the 

 causes of error be removed, those which remain will be 

 detected. 



When any given charge is loaded with a heavy bullet, 

 more of -the" powder is inflamed in any very short space 

 of time than when the bullet is lighter, and the action 

 of the powder ought, of course, to be greater on that 

 account ; but then, a heavy bullet takes up more time 

 in passing through the bore than a light one, and conse- 

 quently more of the elastic, fluid generated from the 

 powder escapes by the vent and by windage. It may 

 happen that the augmentation of the force on account 

 of one of these circumstances may exactly counterbal- 

 ance the diminution of it arising from the other ; and 

 if it should be found upon trial that this is the case in 

 general, in pieces as they are now constructed, and with 

 all the variety of shot that are made use of in practice, 

 it would be of great use to know the fact: and possibly 

 it might answer as well, as far as it relates to the art of 

 gunnery, as if we were perfectly acquainted with, and were 



