PHYSICAL ann LITERARY. 305 
metallic fubftances diffolved in their proper 
acid menfirua, may be precipitated by other 
bodies that are not alcaline, fome by plain 
water, fome by neutral falts, natural or arti- 
ficial; fome by another metal, fome by an- 
other acid liquor; and, laftly, fome of thefe 
folutions may be precipitated intwo or three 
different ways; of all which I fhall give 
inftances afterwards. But further, acid and 
alcaline liquors are not the only folvents; for 
water, ardent fpirits, oils, and feveral com- 
pound liquors, neither acid nor alcaline, dif- 
folve a great many different bodies, which 
likeways may be feparated from them by pre- 
cipitants of different qualities. Therefore an 
_acid and alcali do not always concur to make 
a precipitation. 
| Il, Tue weakening or diluting folutions, 
by aliquor fpecifically lighter than the fol- 
vent, is not the fole caufe of precipitation. 
| Some who would account for precipitati- 
ons upon mechanical principles, contend 
that diminithing the fpecific gravity of the 
-folvent liquors is the caufe of all precipita- 
tions: but this, altho’ it obtains in fome in- 
tances, yet, in many more, it will be found 
contrary to experience. If any falt is diffol- 
Qq ved 
