Experiments upon Gimpowder. 55 



290 grains of powder (from the 48th to the 57th experi- 

 ment inclusive'), the recoil was, 



Vent at o. Vent at 1.3 Vent at 2.6. 



22.58 23.21 23.06 



22.92 23.76 23.26 



22.38 23.06 23.26 



23^56 



3)67.88' 3)70.03 4)93-I4 



Means = 22.626 2 3-343 an d 23.285 



If now we take a mean of the 6oth and 96th experi- 

 ments, and call the recoil, without a bullet, 10.66, as 

 before, the velocities will turn out, 



Vent at o. Vent at 1.3. Vent at 2.6. 



By the recoil, 1416 1501 . .1494 



And by the pendulum they were 1427 1493 1460 



The difference is only n -|- 8 -J- 34 



The recoil was equally regular in the nyth and five 

 succeeding experiments, when the charge was no less 

 than 437-5- grs. ==: i ounce avoirdupois in powder ; and 

 the velocities of the bullets determined from the recoil 

 are very nearly the same as they were shewn by the pen- 

 dulum. Thus, in the H7th, n8th, and ngth experi- 

 ments the mean recoil was 33.3 : and in the iioth, i2ist, 

 and I22d experiments it was 32.866. And if the recoil 

 without a bullet be called i7'-9, as it was determined by 

 the 1 23d experiment, which was made immediately after 

 the experiments before mentioned, then will the veloci- 

 ties be, 



Vent at o. Vent at 2.6. 



By the recoil, 1822 1771 



And by the pendulum they were ^64 '75 1 



The difference is only -|- 58 and -f- 20 feet 



in a second, which is less than what frequently occurs in 

 repeating the same experiment. 



