Experiments upon Gunpowder. 45 



which arises from the particular situation of the vent 

 is extremely small. 



With 165 grains of powder, and the vent at o, the 

 velocity of the bullet, at a mean of two experiments 

 (viz. the 2oth and 2ist), was 1087 feet in- a second; 

 and with the same charge, and the vent at 1.32 inches, 

 the velocity, at a mean of the 22d, 23^, and 24th experi- 

 ments, was 1082 feet in a second ; the difference (equal 

 to five feet in a second) is less than what frequently 

 occurred in a repetition of the same experiment. 



With 218 grains of powder, and the vent at o, the 

 velocity, at a mean in the 4Oth, 4ist, 42d, and 47th 

 experiments, was at the rate of 1225 feet in a second; 

 and with the same charge, and the vent at 1.3, the 

 velocity was 1276 feet in a second, at a mean of four 

 experiments, viz. the 43d, 44th, 45th, and 46th. 



In the first set of experiments, with 290 grains of 

 powder, the velocities were, 



Vent at o. Vent at 1.3. Vent at z.6. 



I4H H76 1502 



1455 1520 1450 



14.12 1483 1433 



1454 

 3)4281 3)4479 4)5839 



Means, 1427 1493 1460 



See the experiments from No. 48 to No. 57, inclusive. 

 In the second set the velocities were, 



Vent at o. Vent at 2.6. 



1419 1438 



1460 1423 



1462 1378 



1436 



4)5777 3)4239 



Means, 1444 1413 



