the Force of Fired Gunpowder. 1 1 3 



them may, nevertheless, be very near the truth ; and this 

 is never so likely to happen as when, from known effects, 

 the action of the powers which produce them are com- 

 puted. For it is not in general very difficult to assume 

 such principles as, when taken together, may in the most 

 common known cases answer completely all the condi- 

 tions required. But in such cases, if the truth be dis- 

 covered with regard to any one of the assumed principles, 

 and it be substituted in the place of the erroneous sup- 

 position, the fallacy of the whole hypothesis will im- 

 mediately become evident. 



As I have mentioned the experiments made with 

 heavy artillery, as having been led by their results to 

 form important conjectures relative to the nature of the 

 expansion of the fluid generated in the combustion of 

 gunpowder; it may perhaps be asked, and indeed with 

 some appearance of reason, what the circumstances were 

 which attended the experiments in question, which could 

 justify so important a conclusion as that of the fallacy 

 of the commonly received theory relative to that subject. 

 To this I answer briefly, that in regard to the supposed 

 instantaneous inflammation of the powder, upon which 

 the vv'hole fabric of this theory is built, or rather of all 

 the computations which are grounded upon it, a careful 

 attention to the phaenomena which take place upon fir- 

 ing off" cannon led me to suspect, or rather confirmed 

 me in my former suspicions, that, however rapid the in- 

 flammation of gunpowder may be, its total combustion is 

 by no means so sudden as this theory supposes. When 

 a heavy cannon is fired in the common vv^ay, that is, 

 when the vent is filled with loose powder, and the piece is 

 fired oflF with a match, the time employed in the passage 

 of the inflammation through the vent into the chamber of 



