ijj^ ESSAYS AND OBSERVATIONS' 



and imperceptible manner, and requires 

 the affiftance of a great external heat. 



The manner in which the acid of fea- 

 falt is applied to quick-filver, in order to' 

 difTolve and be united to it, is ftill more' 

 extraordinary : There are two methods' 

 pradifed, but both depend on the fame 

 |)rinciple, and produce the fame effedl; 

 For, either the quick-filver is rubbed in a 

 marble mortar with green vitriol calcined 

 to whitenefs, decrepitate fea fait, and a 

 fmall proportion of dry falt-petre, till the' 

 quick-filver is extinguifhed and difap- 

 pears, this mafs is put into a fubliming 

 glafs ; a gentle heat rs mad6 at firft, and' 

 gradually increafed ; in the beginning a*« 

 rife white fleams ; if thefe are colledled,- 

 they condenfe into a liquor, which proves 

 a weak aqua regia ; then there will fublime 

 a white ihining chryflaMine body, which- 

 h a vitridl of quick filver, and goes un- 

 der the name of mercurius fiiblimatiu cor^ 

 rofivus : That the quick-filver is here dif- 

 folved by, and united to the acid of fea' 

 fait, with a fmall quantity of the nitrous 

 acid, is evident j becaufe the fame mate- 

 rials. 



