the Force of Fired Gunpowder. 149 



has already been observed, must be attributed to the 

 unavoidable errors of the experiments) are corrected, 

 these two curves will be found to coincide with much 

 precision, throughout a considerable part of the range of 

 the experiments ; but towards the end of the set of ex- 

 periments, when the charges of powder were consider- 

 ably increased, the elasticities seem to have increased 

 faster than, according to the assumed law, they ought to 

 have done. 



From this circumstance, and from the immense force 

 the charge must have exerted in the experiment when 

 the barrel was burst, I was led to suspect that the elastic 

 force of the fluid generated in the combustion of gun- 

 powder, when its density is great, is still much greater 

 than these experiments seem to indicate; and a farther 

 investigation of the subject served to confirm me in this 

 opinion. 



It has been shewn that the force exerted by the charge 

 in the experiment in which the barrel was burst could 

 not have been less than the pressure of 54,752 atmos- 

 pheres ; but the greatest force of the generated elastic 

 fluid, when, the powder filling the space in' which it is 

 confined, its density is ^=^ icoo, on computing^ its elas- 

 ticity by the theorem x'^°°°°'''^ ^= y, turns out to be 

 only equal to 29,178 atmospheres. 



In this computation the mean of the results of all 

 the experiments in the foregoing set is taken as a stand- 

 ard to ascertain the value, expressed in atmospheres, of 

 J/, and it is _)/ X 1.841 = 29,178. 



But if, instead of taking the mean of the whole set of 

 experiments as a standard, we select that experiment in 

 which the force exerted by the powder appears to have 

 been the greatest, yet, in this case, even the initial force 



