Mr. Thompson’s Experiments 
•274' 
A table of experiments , Jhewing the effeSi of placing the vent in 
different parts of the charge . 
Weight of the 
charge of pow- 
1 der. 
Space occupied 
by the powder, 
V ent from the 
bottom of the 
bore. 
Velocity of the 
bullet at a me- 
dium. 
Recoil mea- 
fured upon the 
ribbon at a me- 
d i urn . 
Number of ex- 
periments. 
Grains. 
Inches * 
Inches. 
Ft» in a fee. 
Inches. 
165 
i ,45 
0 
IO87 
14,465 
2 
. . . 
. . . 
U 3 2 
1082 
H, 3 * 
O 
0 
2 1 8 
J >9 
6 
1225 
I 7,93 
4 
. « . 
> . « 
r > 3 ' 
I276 
1^:34 
4 ' 
290 
2,6 
0 
I427 
22,626 
' 
0 
. . . 
• • • 
i >3 
*493 
2 3?34 
3 
• © • 
• • • 
2 v 6 
1460 
23,286 
4 
. . . 
. . . 
0 
1444 
2 3> I 35 
A . 
. . . 
. . . 
2,6 
H *3 
24,5 
3 
3 10 
2 >7 
0 
— 
24,69 
1 
• • • 
. . . 
I, 3 2 
24,95 
1 
. . . 
. . . 
2,65 
24,9 
1 
33 ° 
2 >9 
0 
>594 
26,075 
2 
. . . 
ft • ft 
i>3 
1625 
26,4 
2 
. . . 
ft ft * 
2 5 6 
1525 
2 5>3 
2 
437 i 
3>9 
0 
1764 
33>3 
0 
D 
• V* 
2,6 
* 75 1 
32,866 
3 
By the foregoing experiments it appears, firft, that the dif- 
ference in the force of any given charge of powder which 
arifes from the particular fttuation of the vent is extremely 
fmalh 
With 165 grains of powder, and the vent at o, the velocity 
of the bullet at a mean of two experiments ( viz. the 20th 
and 2 1 ft) was 1 08 7 feet in a fecond; and with the fame charge, 
and the vent at 1,32 inches, the velocity at a mean of the 
zzd 7 23d, and 24th experiments, was 1082 feet in a fecond ; 
