0« a new fulminating Mercury. 977 



been, carbonic acid gas, fulphureous acid gas, nitrogen gas, and (according to Lavolfier *) 

 |>erhap8 hydrogen gas. As to the quantity of thefe gafes, it is obvious that it could not be 

 afcertained ; becaufe the two firft were, at lead in part, ipeedily abforbed by the alkali of 

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



SECTION viir. 



From the experiments related, In the 4th and 5th feftions, in which the gunpowder 

 proof and the gun were burft, it might be inferred, that the aftonilhing force of the mer- 

 curial powder is to be attributed to the rapidity of its combuftion ; and, a train of feveral 

 inches in length being confumed in a fingle flafh, it is evident that its combuftion muft be 

 rapid. From the experiments of the 6th and 7th fe£lions, it is fufficlently plain that this 

 force is reftralned to a harrow limit ; both becaufe the block of wood charged with the 

 mercurial powder Was more (battered than that charged with the gunpowder,- whilft the 

 fand furroi^nding it was leaft difturbed; and likewife becaufe the glafs globe. withftood the 

 exploGon of 10 grains of the powder fixed in its centre : a charge I have twice found 

 fufficicnt to deftroy old piftol barrels, which were not injured by being fired when full of 

 the beft gunpowder. It alfo appears, from the laft experiment, that 10 grains of the 

 powder, produced by ignition fourx:ubical inches only of air; and it is not to be fuppofed 

 that the generation, however rapid, of four cubical inches of air, will alone account for 

 the dcfcribed force ; neither can it be accounted for by the formation of a little water, 

 which, as will hereafter be (hewn, happens at the fame moment : the quantity formed 

 from 10 grains muft be fo trifling, that I cannot afcribe much force to the expanfion of its 

 vapour. The fudden vaporization of a part of the mercury, feems to me a principal caufe 

 of this immenfe yst limited force ; becaufe Its limitation may then be explained, as it is 

 well known that mercury eafily parts with caloric, and requires a temperature of 600 de- 

 grees of Fahrenheit, to be maintained in the vaporous ftate. That the mercury is really 

 converted into vapgur, by ignition of the powder, may be inferred from the thin coat of 

 divided quickGlver, which, after the explofion in the glafs globe, covered its interior 

 furface ; and likewife from the quickfilver with which a tallow candle, or a piece of gold, 

 may be evenly coated, by being held at a fmall diftance from the inflamed powder. Thefe 

 fa£ts certainly render it more than probable, although they do not demonftrate, that the 

 mercury is volatilized ; becaufe It is not unlikely that many mercurial particles are mecha- 

 nically impelled againft the furface of the glafs, the gold, and the tallow. 



As to the force of dilated mercury, Mr. Baume relatcis a remarkable inftance of it, 

 as follows. 



" Un aichymifte fe prcfenta a Mr. GeofFroy, et Taflura qu'il avoit trouve le moyen de 

 " fixer le mercure par unc operation fort fimple. II fit conftruire fix boites rondes en fer 



* See Lavoifier, Traite elementaire, p. 527. 

 Vol. IV — July 1800. A a "fort 



