upon Gun-powder , &c. 283 
The length of the parallel rods by which the barrel was fuf- 
pended being 64 inches, the velocity of the recoilanfwering to 
C - c— 1 inch meafured upon the ribbon is 0,20465 ; parts of a 
foot in a fecond ; and this is alfo, in this cafe the value of 
V-U; the velocity of the bullet is therefore v — 0,204655 x 
579,31 = 118,35 feet in a fecond. 
Confequently the velocity of the bullet exp refled in feet per 
fecond may in all cafes be found by multiplying the difference 
of the chords C, and c, by 1 18,35, the weight of the barrel, the 
length of the rods by which it is fufpended, and the weight of 
the bullet remaining the fame, and this whatever the charge of 
powder may be that is made ufe of, and however it may differ 
in ftrength or goodnefs. 
According to this rule the velocities of the bullets in. the fol- 
lowing experiments have been computed from the recoil ; and 
by comparing them with the velocities fhewn by the pendulum, 
we fliall be enabled to judge of the accuracy of this new me- 
thod of determining the velocities of bullets. 
In the 76th and 77th experiments, when the piece was fired' 
with 145 grains of powder and a bullet, the recoil was 13,25 
and 13,15, or 13,2 at' a mean; and with the fame charge of 
powder, without a bullet, the recoil was 4,5- and 4,3, or 4,4 
at a mean (fee the 84th and 93d experiments). C — c is 
therefore 13,2 —4,4 = 8,8 inches, and the velocity of the bul- 
lets = 8,8 x- 1 18,35 rr 1045 feet a fecond. The mean of 
the velocities as they were determined by the pendulum is that 
of 1040 feet in a fecond. In tjie 104th and 105th experiments- 
the recoil was 12,92: and 13,28, and the velocity computed, 
from the mean of thofe chords is 1030 feet in a fecond; but 
the velocity flie.w-n by the pendulum was no more than; about 
900 feet in a "fecond. As the recoil was fo nearly equal to> 
