COMBINATION OF MERCURY 



V 



tiire *. The yellow or afn-coloured powder men- 

 tioned above, if mixed with afuflicicnt quantity 

 of crude mercury, and again fublimed, can be 

 converted into fwect mercury ; it is therefore by 

 no means to be thrown nfulc:us ufelefs, as is com- 

 monly done, on the authority of pharmaceuti- 

 cal writings. 



The firil procefs being ended, maiiy chemiils 

 direct the afli-coloured po\vder to be fepa rated, 

 and the folid faline mafs, either alone, or mixed 

 with as much crude mercury as it can extinguish, 

 to be again and even fevcral times fublimed. In 

 this way they at Jail judge it to be properly called 

 incrcurlus dulcis. In our laboratories, however, 

 the fublimation is feldom repeated more than 

 twice. The French reckon frequent fublima- 

 tions of great importance; and after three are 

 made with addition of crude mercury and three 

 without.it, they name that calomel or cu/outf/as 

 which is obtained by the lad fublimation. This 

 appellation is however fuflidently abfurd, and 

 ciiticifed by many f ; with us it is commonly giv- 

 en to the mercurius dulcis, which is produced 

 by the firil: fublimation. La lirune has gone 

 yet further, and added greatly to the labour of 

 this preparation, in fubliming fweet mercury 



nine 



* Confp. Chtm. 



t See Lewis's notes uponfcWIlfon's Courfe of Chcim'ftrr, 

 J735. and the author of the book: Efiay fora rctormatiun 

 of the London Pharmacopoeia. 



