300 ESSAYS anv OBSERVATIONS 
intirely change the nature of fome of thefe 
folvent liquors. 
To begin with fome familiar inftances to - — 
confirm our remark. Water can diflolve a 
certain quantity of any falt; yet, when it is 
fully impregnated with one falt, it will ftill 
diffolve a portion of another falt, tho’ not 
fo much as the fame quantity of pure water 
would do. From fea water, by evaporation and 
chyftallization, are procured three diftindt 
falts, befides other fabftances, as the ingeni- 
ous Mr Brown has obferved, viz. the muria+ 
tic, or falt for common ufe, the bitter pur- 
ging falt, and a fiery calcarious falt, different 
from the other two; yet fea-water will 
diffolve, at the fame time, a pretty confider- 
able quantity of feveral other falts, as fugar, 
falt athmoniac, falt petre and falt of tartar ; 
and, after it has diffolved fufficiently of two 
or more of thefe falts, it will, even then, 
diffolve fome more fea falt, and {till more of 
the epfom or Glauber’s falt. Hence, by the 
way, we find fuch a variety of mineral or 
medicinal waters, impregnated in various 
proportions, with different falts, vitriols, me- 
tals, earths, &c. The acid of fea falt, which 
has diffolved quick-filver, and chryftallized 
with 
