i8 



Experiments upon Gunpowder. 



Finding that the blast of the powder always reached 

 as far as the pendulum, when large charges were used, 

 and suspecting that this circumstance, together with the 

 impulse of the unfired grains, might, in a great measure, 

 occasion the apparent irregularity in 'the velocities of 

 the bullets ; to remedy these inconveniences, a large 

 sheet of paper of a moderate thickness was stretched 

 upon a square frame of wood, and interposed as a screen 

 before the pendulum, at the distance of two feet from 

 the surface of the target. 



Two reasons conspired to induce me to prefer this 

 method of preventing the impulse of the flame upon 

 the pendulum, to the obvious one of removing the pen- 

 dulum further from the mouth of the piece ; the first 

 was, that I was unwilling to increase the distance between 

 the barrel and the pendulum, lest the resistance of the 

 air might affect the velocities of the bullets ; and the 

 second, which I confess did not operate less strongly 

 than the first, was that the length of the house did not 



