312 ESSAYS ano OBSERVATIONS 
powder of an afh colour, which being dried, 
a little exceeds the weight of the filver dif- 
folved. a 
The precipitations of mercury fhew ftill 
a greater variety, at leaft, as to their effects, 
being afed as medicines. If fea falt, diffol- 
ved im 2 good quantity of water, is put 
into a folution of quick-filver in agua fortis, 
it turns the clear and limpid folution turbid, 
opaque and milky; at length the white mat- 
ter fubfides, which being feparated from the 
fluid, wafhed and dried, remains a very white | 
powder, and a little exceeds the weight of 
the quick-filver diffolved: but it is to be ob- 
ferved, that the muria does not precipitate all 
the mercury ; for the liquor, thus feparated 
from the white powder, is known to have the 
effects of a cofmetic or deterfive mercurial 
water ; befides if o/. tart. p. d.is dropt into this 
liquor, a fmall quantity of a brown mercurial 
powder will be precipitated. Phyficians know 
that this white precipitate is a pretty active 
and brifk medicine, and produces greater ef- 
fects, even in a fmaller dofe, than calomel, 
but is more mild and tractable than the merc. 
fublim, corrofivus; for, when this laft is fome- 
what tempered by /prr. fal. ammon. it be- 
comes 
ee a 
