Experiments 'upon Gunpowder. 65 



This difference is undoubtedly owing to the recoil 

 without a bullet being taken too great, for it is not only 

 greater than it ought to be> in order that the velocities 

 of the bullets may come out right, but it is considerably 

 greater in proportion than the recoil with any other 

 charge. 



Thus, with 145 grains of powder the recoil was 4.4 

 with 165 grains it was 5.55 



290 grains 10.66 



330 grains 12.7 



and with 437^ grains it was 17.9 



And if the recoil with 218 grains is determined from 

 these numbers by interpolation, it comes out 7.5; and 

 with that value for C, the velocities of the bullets in the 

 before-mentioned experiments appear to be, 



Vent at o. Vent at 1.3. 



1243 and 1283 by the recoil 



which is extremely near 1225 and 1276 the 'velocities 

 shown by the pendulum. 



It is to be remembered, that the yid and 73d experi- 

 ments, from which we before determined the recoil with 

 the given charge of powder without a bullet, were not 

 made upon the same day with the experiments before 

 mentioned ; and it is well known that the force of pow- 

 der is different upon different days. And it is worthy 

 of remark, that in those two experiments the strength 

 of government powder appeared to be considerably the 

 greatest. I mention these circumstances to shew the 

 probability there is that the recoil in those experiments, 

 from some unknown cause, was greater than it ought to 

 have been, or rather than it would have been had the 

 experiments been made at the same time when the experi- 

 ments with the bullets were made, or at any other time 



under the same circumstances. 

 VOL. i. 5 



