upon Gun-powder , &c. 281: 
Let us fee how this method of determining the velocities of 
bullets will anfwer in practice. 
In the 94th experiment the recoil, with 165 grains of pow- 
der, without a bullet, was 5,5 inches, and in the 95th experi- 
ment, with the fame charge, the recoil was 5,6 inches. The 
mean is 5,55 inches ; and the length of the rods by which the 
barrel was fufpended being 64 inches, the velocity of the recoil 
(= U) anfwering to 5,55 inches meafured upon the ribbon, is 
that of 1,1358 feet in a fecond. 
In five experiments, with the fame charge of powder, and a 
bullet weighing 580 grains, the recoil was as follows, viz,. 
The 2oth| experiment 14,73 inches 
2 1 ft 
14,2 
2 2d 
1 4,8 
2 3 d 
1-4,58 
24th 
14,68 
5)73, (= 14,6 inches, at a mean. 
And the velocity of the recoil ( = V) anfwering to the length 
is that of 2,9880 feet in a fecond : confequently V-U, or 
2,9880 - 1,1358 is equal to 1,8522 feet in a fecond. 
But as the velocities of recoil are known to be as the chords 
of the arcs through which- the barrel'afcends, it is not neceftary 
in order to determine the velocity of the bullet to compute the 
velocities V and U ; but the quantity V-U, or the difference 
of the velocities of the recoil when the given charge is fired 
with and without a bullet, may be computed from the value 
of the difference of the chords, by one operation. Thus the 
velocity anfwering to the chord 9, 05. is that of 1,8522 feet in 
a fecond, which is juft equal to V -U, as was before found. 
The 
