2io A SYSTEM OF 



the earlieft times, being then reckoned among the 

 metals, when even they were named after the 

 planets, the number of both being thought equal. 



The opinion, which has a long time prevailed, 

 that the quickfilver is a necefTary ingredient, and 

 conftituent part in all metals, is not fo generally 

 received now as heretofore •, fince thofe proceffes, 

 which have been-. advanced as proofs of it, and 

 which have, however, but feldom been repeated, 

 do by no means fucceed, at lead not in all places *, 

 it is rather fuppofed, that by the mercurial earth 

 the ancients have underftood an earth,, which may, 

 by addition of phlogiftora, be reduced in the fire 

 to a metallic ftate ; and this appears to be fo much 

 the more reafonable, as the quickfilver only attracts 

 the metals in their fubftances* and not in. their 

 burnt calces, 



SECT, cexxr. 



2. Bifmuth, Tinglafs, Vifmutum, Bifmutum^ 

 Marcafita officinalis. It is 



a. Of a whitifh yellow colour. 



b. Of a laminated texture, foft under the 

 hammer, and neverthelefs very brittle. 



c. Its fpecific gravity to water is, as 9,700 : : 

 1000. 



d. It is very fufible, calcines an ^ fcorifies like 

 lead, if not rather eafier, and therefore 

 it works on the cuppel. It is pretty vola- 

 tile in the fire. 



e. Its glafs or flag becomes yellowifh brown, 

 and has the quality of retaining fome part 

 of the gold, if that metal has been melted, 

 calcined, and vitrified with it. 



f. It may be mixed with the other metals, ex- 

 cept cobalt and zink, making them white 

 and brittle. g. It 



