upon Gun-powder , 3 1 1 
pre-fibre was only as 0,5825 ; and in the 85th, 86th, and 
87th experiments, when the bullets were much lighter, the 
action, of the charge was hill lefs. 
But though we can determine with great certainty, from 
thefe experiments, the ratio in which the action of the powder 
upon the bullet was increafed or diminifhed, by making ufe of 
bullets of greater or lefs weight ; yet we cannot from thence 
afcertain the relation of the elafiicity of the generated fluid to 
its denflty, nor the quantity of powder that is inflamed at dif- 
ferent periods before and after the bullet begins to move in the 
bore. 
But afluming Mr. Robins’s principles as far as relates to the 
elafiicity of the fluid, and fuppofing that in all the experiments, 
except the 9 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 preflure. 
Thus, if the whole charge, = 1 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 f 2 
