the Force of Filled GiLiipowder. loi 



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 \ 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 2V 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 



