Sis Onn new fulminating Mercury. 



connedled with tlie brafs caps, the packet of powder became, 

 bv this difpofition, fixed in the centre of the globe. Such 

 a charge of an ele6lrical battery was then fent along th6 

 wire, as a preliminary experiment* had fhovvn me would, 

 by making the wire red-hot, inflame the powder. The glafs 

 globe withftood the explofion, and of courfe retained what- 

 ever gafes were generated : its interior was thinly coated with 

 quickfilver in a very divided ftate. A bent glafs tube was 

 now fcrewed to the ftop-cock of the brafs cap, which being 

 introduced under a glafs jar {landing in tlie mercurial bath, 

 the ftop-cock was opened. Three cubical inches of air 

 rufhed out, and a fourth was fet at liberty when the appa- 

 ratus was removed to the water-tub. The explofion being 

 repeated, and the air all received over water, the quantity 

 did not vary. To avoid an error from change of tempera- 

 lure, the glcifs globe was, both before and after the explofion, 

 imnierftd in water of the fame temperature. It appears, 

 therefore, that the ten grains of powder produced four cu- 

 bical inches only of air. 



To continue the comparifon between the mercurial powdeif 

 and gunpowder, ten grains of the heft Dartford gunpowder 

 were in a fimilar manner fet fire to in the glafs slobc : it re- 

 mained entire. The whole of the powder did not explode, 

 for fome complete grains were to be obferved adhering to the 

 interior furface of the glafs. Little need be faid of the na- 

 ture of the gafes generated during the combuftion of gun- 

 powder : they muft have been carbonic acid gas, fulphureous 

 acid gas, nitrogen gas, and (according to Lavoifier f) per- 

 haps hydrogen gas. As to the quantity of thefe gafes, it is 

 obvious that it could not be afcertained ; becaufe the two 

 firft were, at leaft in part, fpeedily abforbed by the alkali of 

 the nitre, left pure after the decompolition of its nitric acid. 



Section VIII. 

 From the experiments related in the 4th and 5th fctSlions, 

 in which the gunpowder proof and the gun were burft, it 

 might be inferred, that the aftonifhing force of the mercurial 



* With Mr. Cuthbertfon's eleftrometer. 

 t See Lavoifjcr, Trahi (knunlatre, p. 527. 

 » powder 



