64 Experiments upon Gunpoivder. 



pose the full resistance to have begun so near as two feet 

 from the mouth of the piece; and in all cases where the 

 velocities were less, the effect of the resistance was less 

 in a much greater proportion ; and even in this instance 

 there is reason to think that the diminution of the ve- 

 locity, as we have determined it, is too great ; for the 

 flame of gunpowder expands with such an amazing 

 rapidity that it is scarcely to be supposed but that it 

 follows the bullet and continues to act upon it more 

 than two feet, or even four feet, from the gun, and when 

 the velocity of the bullet is less, its action upon it must 

 be sensible at a still greater distance. 



With 218 grains of powder, the recoil appears to have 

 been very uniform ; but if the velocities of the bullets 

 are determined from the recoil in the 4<Dth and seven fol- 

 lowing experiments, when this charge was made use of, 

 and from the recoil without a bullet in the yid and yjd 

 experiments, the velocities will turn out considerably 

 too small, as we shall see by making the computation. 



Vent at o. Vent at 1.3. 



f 40th exp. was 18. and in the 43d exp. it was 18.3 



The recoil I 4ist 17.71 44 h '8-35 



in the 1 42d 17.91 45th 18.35 



i 47th 18. i 46th 18.35 

 4)71-72 



Means = 17.93 and 18.34 



And in the ysd and yjd experiments the recoil, with 

 the same charge without a bullet, was 8.72 and 8.47 = 

 8.595 at a medium ; the velocities therefore turn out, 



Vent at o. Vent at 1.3. 



By the recoil 1105 1153 



instead of 1225 and 1276 as they were shown by the pend. 



The diff. 120 and 123 feet in a second amounts to 

 near one twelfth part of the whole velocity. 



