ACTION OF THE POWDER ON THE PROJECTILE. 181 



is fired and converted into an elastic fluid, before the 

 bullet (or charge of shot) is sensibly moved from its place. 

 This proposition he attempts to demonstrate as follows: 

 " It might perhaps be sufficient for the proof of this position 

 to observe the prodigious compression of the flame in the 

 chamber of the piece. Those who will attend to this circum- 

 stance, and to the easy passage of the flame through the 

 intervals of the grains, may soon satisfy themselves that no 

 one grain contained in that chamber can continue for any 

 time uninflamed when thus surrounded and violently pressed 

 by so active a fire. However, not to rely on a mere specu- 

 lation on a point of so much consequence, I considered that 

 if part only of the powder is fired, and that successively, then 

 by laying a greater weight before the charge (suppose two or 

 three bullets instead of one), a greater quantity of powder 

 would necessarily be fired, since a heavier weight would be a 

 longer time in passing through the barrel. Whence it should 

 follow that two or three bullets would be impelled by a much 

 greater force than one only. But the contrary of this appears 

 by experiment, for firing one, two, and three bullets laid 

 contiguous to each other, with the same charge respectively, 

 I have found (by a method to be mentioned hereafter) that 

 their velocities were not much different from the reciprocal 

 of the subduplicate of their quantities of matter ; that is, if 

 a given charge will communicate to one bullet a velocity of 

 1700 feet in 1", the same charge would communicate to two 

 bullets a velocity from 1250 to 1300 feet in 1", and to three 

 bullets a velocity from 1050 to 1100 feet in 1". From hence 

 it appears that, whether the piece be loaded with a greater or 

 less weight of bullet, the action of the powder is nearly the 

 same, since all mathematicians know that, if bodies containing 

 different quantities of matter are successively impelled through 

 the same space by the same power, acting with a determined 

 force at each point of that space, then the velocities given to 

 those different bodies will be reciprocally on the subduplicate 

 ratio of their quantities of matter. The excess of the velo- 

 cities of the two and three bullets above what they should 

 have been by this rule (namely, 1200 and 980 each in 1"), 

 does doubtless arise from the flame, which, escaping by the 

 side of the first bullet, acts on the surface of the second and 



