The Force of Fired Gunpowder. 99 



which takes place in the inflammation of gunpowder, 

 and the nature and properties of the elastic fluids gen- 

 erated in its combustion. But the ^reat desideratum, 

 the real measure of the initial expansive force of in- 

 flamed gunpowder, so far from being - known, has 

 hitherto been rather guessed at than determined ; and 

 no argument can be more convincing to shew our total 

 ignorance upon that subject, than the difference in the 

 opinions of the greatest mathematicians of the age, who 

 have undertaken its investigation. 



The ingenious Mr. Robins, who made a great num- 

 ber of very curious experiments upon gunpowder, and 

 who, I believe, has done more towards perfecting the art 

 of gunnery than any other individual, concluded, as the 

 result of all his inquiries and computations, that the 

 force of the elastic fluid generated in the combustion of 

 gunpowder is 1000 times greater than the mean pressure 

 of the atmosphere. But the celebrated mathematician 

 Daniel Bernouilli determines its force to be not less 

 than 10,000 times that pressure, or ten times greater 

 than Mr. Robins made it. 



Struck with this great difference in the results of the 

 computations of these two able mathematicians, as well 

 as with the subject itself, which appeared to me to be 

 both curious and important, I many years ago set about 

 making experiments upon gunpowder, with a view princi- 

 pally of determining the point in question, namely, its 

 initial expansive force when fired ; and I have ever since 

 occasionally, from time to time, as I have found leisure 

 and convenient opportunities, continued these inquiries. 



In a paper printed in the year 1781, in the LXXI. 

 Volume of the Philosophical Transactions, I gave an 

 account of an experiment (No. 92), by which it ap- 



