upon Gun-powder , Sec. 30 y 
prove, that the inflammation of gun-powder is inftantaneous, 
or that the whole charge is in all cafes inflamed, and “ con- 
44 verted into an elaftic fluid before the bullet is fenfibly moved 
44 from its place fuch reafonings and conclufions may lead to 
very dangerous errors. 
It is undoubtedly true, that if the principles aflumed by Mr. 
robins with refpeff to the manner in which gun-powder takes 
Are, and the relation of the elafticity of the generated fluid to 
its denfity, or the intenlity of its preffure upon the bullet as it 
expands in the barrel, were juft, and if the lofs of force by the 
vent and windage was in all cafes inconfiderable, or if it was 
prevented, the dedudlions from the theory refpefling the velo- 
cities of bullets of different weights would always hold good. 
But if, on the contrary, it Humid be found upon making the- 
experiments carefully, and in fuch a manner as mtirely to pre- 
vent inaccuracies arifing from adventitious circumftances, that 
the velocities obferve a law different from that which the theory 
fuppofes, we may fairly conclude, that the principles upon 
which the theory is founded are erroneous. 
Let us now fee how far thefe experiments differ from the 
theory. Thofe numbered from 84 to 92 inclufive were made 
in fuch a manner that no part of the force of the powder was 
loft by the vent, or by windage, as- has already been mentioned, 
and all poffible attention was paid to every circumftance that 
could contribute to render them perfect and conclufive. 
A particular account of them with the means u fed for form- 
ing the bullets, and making them fit for the bore, and the con- 
trivance for preventing the efcape of the elaftic fluid by the 
vent, &c. may be feen in the general table, p. 245. The fol- 
lowing table Ihews the refult of them. 
3, N- Bl 
