Chap. 33.] Tur&itb Mineral. 207 



concentrated and confiderably heated ; it then corrodes 

 it into a white mafs, and the vitriolic acid is rendered 

 partly volatile by the abftraction of oxygen. The 

 greatefl part of this mafs, which weighs confiderably 

 more than the mercury made ufe of, is a calx of mer- 

 cury united to a fmall portion of vitriolic acid, but 

 part of it is a perfect fait, formed by the union of the 

 vitriolic acid and mercury. If boiling water is added 

 to it, it aflufnes a bright lemon colour, which is owing 

 to the abftracYion of the vitriolic acid, the pre'fence of 

 which rendered the mafs white. The more boiling 

 water is ufed the yellower is the remaining powder, 

 which, after repeated effufions of water, is found to 

 have no caufticity, and to be nearly a pure calx of 

 mercury. This is the fubltance known under the 

 name of turbith .mineral. The water, which has been 

 poured on the vitriolic mercurial mafs, is found to con- 

 tain a confiderable quantity of vitriolic acid united to 

 the calx of mercury. 



The nitrous acid is decompofed by mercury with 

 the greateft rapidity. Strong nitrous acid will take 

 up its own weight of mercury in the cold, and this 

 folution will bear to be diluted with water. If the 

 folution is made by the afiiftance of heat, a much, 

 larger quantity is diffolved ; but a precipitate is pro- 

 duced by the addition of water. If cold water is 

 employed, a white precipitate is afforded, but if hot 

 water the precipitate is of a yellow colour, and greatly 

 refembles the turbith mineral produced by the vitriolic 

 acid. If acid is added to the folution produced by 

 heat, it is not decompofed by water. This folution 

 is very ponderous and acrid, and ftains the fkin of a 

 deep purple, inclining in appearance to black, a por- 

 tion of the mercury being precipitated by the animal 

 matter, while the -acid acls on it. Cauftic alkali, 



added 



