Chap. 7.] General Properties cfHepctic Gas. 403 



i ft. Hepatic gas is very foluble in water, which ic 

 converts into a ftate perfectly refembling that of ful- 

 phureous mineral waters, ad. It detonates with vital 

 air when fet on fire. 3d. It is <flot clearly afcertained 

 in what manner fulphur is fufpended in hepatic gas. 

 Sulphur melted by a burning glafi, in inflammable air 

 over mercury, produces a fluid which has the proper- 

 ties of hepatic gas ; and if inflammable air is paflM 

 through fulphur in fufion it is converted into hepatic 

 gas. 4th. The fmellof this air is very unpleafant, and 

 its vapour has a very difagreeable effect upon many 

 metallic fubftances, particularly filver, lead, copper, 

 &c. deftroying their colour, and rendering them al- 

 moft black. 5th. It is extremely pernicious in refpi- 

 ration. 6th. It may be decompofed by vitriolic and 

 nitrous air, by vital air, and by the contaft of atmo- 

 fpheric air, in which cafe it depofits fome fulphur. Its 

 great attraction for fome of the metals and their calces, 

 makes it the bafis of fome fympathetic inks. 



The volatile alkali, and moft of the acids, may be 

 made to afiume an aerial form, and have been diftin- 

 guifhed under the appellation of alkaline and acid airs; 

 it is unnecefiary, however, to introduce the fubjedl in 

 this place, and it will be better underftood when the 

 acids and alkalies are treated of, as they will be in the 

 fucceedins; book. 



Dd 2 



