the Force of Fired Gttnpowder. 121 



which the experiments were made ; of the various pre- 

 cautions used ; and the particular appearances which 

 were observed in the prosecution of them. 



The powder made use of in these experiments was of 

 the best quality, being that kind called poudre de chasse 

 by the French, and very fine grained ; and it was all 

 taken from the same parcel. Care was taken to dry it 

 very thoroughly, and the air of the room in which it 

 was weighed out for use was very dry. The weights 

 employed for weighing the powder were German apothe- 

 cary's grains, 104.8 of which make 100 grains Troy. I 

 have reduced the weights employed to confine the elastic 

 vapour generated in the combustion of the powder from 

 Bavarian pounds, in which they were originally expressed, 

 to pounds avoirdupois. The measures of length were 

 all taken in English feet and inches. The experiments 

 were all made in the open air, in the court-yard of the 

 arsenal at Munich ; and they were all made in fair 

 weather, and Between the hours of nine and twelve in 

 the forenoon, and two and five in the afternoon ; but the 

 barrel was always charged, and the extremity of the bore 

 closed by its leather stopper, in the room where the 

 powder was weighed. In placing the barrel upon the 

 block of stone, great care was taken to put it exactly 

 under the center of gravity of the weight employed 

 to confine the generated elastic vapour. Upon applying 

 the red-hot ball to the vent tube, and fixing it in its 

 place by its lever which supported it, the explosion 

 very soon followed. 



When the force of the generated elastic vapour was 

 sufficient to raise the weight, the explosion was attended 

 by a very sharp and surprisingly loud report ; but when 

 the weight was not raised, as also when it was only a 



