270 Mr. Thompson’s Experiments 
Of the relation of the velocities of bullets to the charges of powder 
by which they are impelled. 
It appears by all the experiments that have hitherto been 
made -upon the initial velocities of bullets, that when the 
weights and dimen Cons of the bullets are the fame, and they 
are difcharged from the fame piece by different quantities of 
powder, the velocities are in the fub- duplicate ratio of the 
weights of the charges very nearly. 
The following table will fhew how accurately this law ob- 
tained in the foregoing experiments. 
Velocities 
Charges, 
437 i 
. Computed. 
1764 
Actual. 
1764 
Difference. 
N° of exp. 
3 
33 ° 
*533 
*594 
+ 61 
2 
3 l ° 
i486 
1459 
- 27 
1 
290 
i 43 6 
1436 
0 
7 
218 
1232 
1225 
- 7 
4 
208 
I2l6 
1256 
+ 40 
3 
165 
1083 
1087 
+ 4 
2 
*45 
IOl8 
1040 
+ 22 
2 
104 
860 
757 
- 103 
2 
The com 
Lputed velocities, 
as they are 
fet down in 
this table. 
were determined from the ratio of the fquare root of 437! (the 
weight in grains of the largeft charge of powder) to the 
mean velocity of the bullet with that charge and the vent at 
o ; viz. i ;64 feet in a lecond, and the fquare root of the other 
charges exprefled in grains. And the adlual velocities are means 
of all experiments that were made under fimilar circumftances. 
S The 
