the Force of Fired Gunpowder. 101 



ternal diameter was i\ inches. It was closed at both 

 ends by two long screws, like the breech-pin of a mus- 

 ket ; each of which entered two inches into the bore, 

 leaving only a vacuity of i inch in length for the charge. 



The powder was introduced into this cavity by taking 

 out one of the screws or breech-pins ; which being after- 

 wards screwed into its place again, and both ends of the 

 barrel closed up, fire was communicated to the powder 

 by a very narrow vent, made in the axis of one of the 

 breech-pins for that purpose. The chamber, which was 

 I inch in length, and f of an inch in diameter, being 

 about half filled with powder, I expected that when the 

 powder should be fired, the generated elastic fluid being 

 obliged to issue out at so small an opening as the vent, 

 which was no more than ^V of an inch in diameter, in- 

 stead of giving a smart report, would come out with 

 something like a hissing noise ; and I intended, in a 

 future experiment, to confine the generated elastic fluid 

 entirely by adding a valve to the vent, as I had done in 

 some of my experiments mentioned in the preceding 

 paper. But when I set fire to the charge (which I took 

 the precaution to do by means of a train), instead of a 

 hissing noise, I was surprised by a very sharp and a 

 very loud report ; and, upon examining the barrel, I 

 found the vent augmented to at least four times its 

 former dimensions, and both the screws loosened. 



Finding, by the result of this experiment, that I had 

 to do with an agent much more troublesome to manage 

 than I had imagined, I redoubled my precautions. 



As the barrel was not essentially injured, its ends were 

 now closed up by two new screws, which were firmly 

 fixed in their places by solder, and a new vent was 

 opened in the barrel itself. As both ends of the barrel 



