334 COMBINATION Oi- MERCURY 



labour is no doubt the bed. Mercury diflblved 

 in the nitrous acid precipitates all thofe falts 

 containing vitriolic acid. Therefore turpcth 

 mineral, or vitriolated mercury, can be prepared 

 at a very (mail expcnce, if vitriol is added to a 

 nitrous folution of mercury, or if even the ar- 

 canum duplicatum is employed, which is ob- 

 tained from the diftillers of aquafortis at a very 

 low rate. In this procefs there is little ground 

 for appreheniion from the vapours of the nitrous 

 acid, which may be entirely avoided by fepa- 

 rating the vitriolic acid from the mercury by 

 means of did illation, (vide 8.). When tur- 

 peth mineral is triturated with common fait, it 

 throws off afli-colourcd vapours, highly often five 

 to the lungs ; but thcfc may be borne much 

 more eatily than the nitrous vapours, and efpe- 

 cially if the mixture is made quickly and in 

 fmall quantity. If the mats is now cxpofed to 

 the fire, corrofive fublimutc of the molt perfecl 

 kind wiJl be collected in the head of the fub lim- 

 ing veflel : The rcfiduuiu at the bottom is a 

 Glauber's fait, which, for the purpofcs of medi- 

 cine, mull fuller again the action of fire, in or- 

 der to expel any portion of mercury that may 

 be yet adhering to it. It is not ncccfTary for 

 this operation to purify the common fait of all 

 the earthy falts that are combined with it, of 

 which we have already fpoken above, ($6). 

 Hence it is only required to dry the mixture, ib 



