7 8 'Experiments itpon Gunpowder. 



between the experiment and the theory, or the number 

 of feet in a second by which the actual velocity exceeded 

 the computed. 



But in order that we may see this matter in different 

 points of view, let the order of the experiments be now 

 inverted, and let the computed velocities be determined 

 from the actual velocity in the 92d experiment ; and as- 

 suming the total or collective pressure exerted by the 

 power upon the bullet in that experiment equal to unity, 

 let the collective pressure in the other experiments be 

 computed from the ratio of the actual to the computed 

 velocities, and the table will stand thus : 



In the following figure let A B represent the axis of 

 the piece, and A P the length of the space filled with 

 powder ; and at the point P let the perpendicular P H 

 be erected, upon which let P L and P M be taken from 

 P towards H of such magnitudes that while P L ex- 

 pounds the uniform force of gravity, or the weight of 

 the bullet, P M shall be as the force exerted by the pow- 

 der upon the bullet, at the moment of the explosion. 

 If now we suppose that while the bullet moves on from 

 P towards B, the line P M or pm goes along with it, and 

 that the point m is always taken ia such a manner that 



