WITH THE MARINE ACID. 327 



tier to forward the extinction of the mercury, 

 which would be othcrwife tedious and difficult, 

 it is ufual to add a fmuii quantity of dried clay. 

 Daily practice has fanc'tioned this proccfs 5 and 

 we find it recommended by N. Le Fevre, who 

 directs four repeated fublimati-ms *. Alfo, in the 

 Brandenburg Difpenfutory, by Rlancard j ; by 

 J. F. CarthcufcrJ; II. F. Tcichmcycr i ; R. A. 

 Vogel (I ; Wallcrius ^]\ and others. We arc 

 told by Tachcnius, tiiat the Venetians prepare 

 great quantities of the mercurial fublimatc ac- 

 cording to this method. They mix together 

 280 pounds of crude mercury, with 20 pounds 

 of corrofivc fublimate, and then, with great care, 

 and variety of apparatus, they add 400 pounds 

 of common fait, 200 pounds of vitriol, and 50 

 pounds of colcothar. Fifteen vcflels arc employ- 

 cd in this operation, and the fire being conti- 

 nued for fifteen days, they obtain at laft 360 

 pounds of corrofivc mercury**. Junker met with 

 a Portuguefc Jew at Amflcrdam, ufmg the fame 

 procefs; the theory of which may be very ea- 

 lily undcrflood. The action of heat, and the 

 mutual affinity between the Vitriolic acid and 

 X 4 the 



* Cours <Ic Chcmlc, 1660. 



f Chcmia. 



J Pharmarologia, 1745. 



^ Inft. Chim, 1729. 



j| Init.Ciicm. 1755. 



5 Chcm. Phyf. vol iii. 



** Tachcnitis in Hippoc. Chcm. 



