upon Gun-powder , &c. 3 1 1 
p failure was only as 0,5825; and in the 85th,. 84th, apd 
87-th experiments, when the bullets were much lighter, ttys 
a&ionof the charge was ftiil lefs. > . ( i 
But 'though we can determine with great certainty, froiyi 
thefe experiments, the ratio in which the action of the powder 
upon the bullet was increafed or diminilhed, by making ufteqf 
bullets of greater or lefs weight ; yet we cannot from thence 
afcertain the relation of the elafticity of the generated fluid to 
its denfity, nor the quantity of powder that is inflamed at dif- 
ferent periods before and after the bullet begins to move in the 
bore. ■ 
But affirming Mr. robins’s principles as far as relates to the 
elafticity of the fluid, and fuppofmg that in all the experiments, 
except the $2d, a part only of the charge took fire, and that 
that part was inflamed and converted into an elaftic fluid before 
the bullet began to move ; upon that fuppofition we can deter- 
mine the quantity of powder that took fire in each experiment ; 
for the quantity of powder in that cafe would be as the collec- 
tive prefl'ure. 
Thus, if the whole charge, = x 45 grains in weight, is fup- 
pofed to have been inflamed in the 92d experiment, the quan- 
tity inflamed in each of the other experiments will appear to 
have been as follows ; viz. 
T t 2 Weight 
