Experiments 7Lpon Gunpowder. 6 



o 



pendulum. I confess I did not then pay much atten- 

 tion to this circumstance, as I naturally concluded that 

 it arose from the breaking of the bullet in penetrating 

 the target of the pendulum, and that the small pieces of 

 plaster I saw upon the ground had fallen out of the 

 hole by which the bullet entered. But if the bullets 

 were not absolutely broken in pieces in the firing, yet if 

 they were considerably bruised, and the plaster, or a 

 part of it, were separated from the lead, such a change 

 in their form might produce a great increase of the re- 

 sistance, and even their initial velocities might be affected 

 by it; for their form being changed from that of a globe 

 to some other figure, they might not fit the bore, and 

 a part of the force of the charge might be lost by the 

 windage. 



That this actually happened in the 87th experiment 

 seems very probable, as the velocity with which the bul- 

 let was projected, even as it was determined by the recoil, 

 is considerably less, in proportion, in that experiment, 

 than in either of those that precede it in that set, or in 

 those which follow it, as will appear upon inspecting the 

 curvature of the line m^ n^ Fig. 16. But I forbear to 

 insist further upon this matter. 



As I have made an allowance for the resistance of the 

 air in these experiments, it may be expected that I 

 should do it in all other cases ; but I think it will ap- 

 pear, upon inquiry, that the diminution of the velocities 

 of the bullets on that account was, in general, so incon- 

 siderable that it might safely be neglected ; thus, for 

 instance, in the experiments with an ounce of powder, 

 when the velocity of the bullet was more than 1750 

 feet in a second, the diminution turns out no more 

 than about 25 or 30 feet in a second, though we sup- 



