T. S. Hunt on the Chemistry of Natural Waters, 185 
more soluble and uncrystallizable compounds, may also be sup: 
od to impregnate, in some cases, the sediments of these salif: 
erous formations. ‘The conditions under which these various 
ts are deposited from sea-water, and their relations to the com- 
periments on the mutual action of the waters of these two 
classes.° When a dilute solution of bicarbonate of soda is grad- 
ually added to a solution which, like sea-water, contains® besides 
chlorid of sodium, the chlorids and sulphates of calcium and 
magnesium, the greater part of the lime separates as carbonate, 
carrying down with it only from one to th ree-hundredths of car-. 
hate of magnesia; a portion of lime however remaining in 
Solution as bicarbonate. When the chlorid of caleium is wholly 
posed, the magnesian salt is attacked in its turn, and there 
finally results a solution in whith the whole of the earthly 
chiorids are replaced by chlorid of sodium. A farther addition 
of the solution of carbonate of soda gives them the character of 
alkaline-saline waters; which moreover contain abundance o 
earthy carbonates, 
€ substitution of neutral carbonate for bicarbonate of soda 
In the above experiment does not affect the result, except in 
*ausing a somewhat larger proportion of magnesia to be thrown 
down with the carbonate of lime. The resulting liquid still re- 
tains large quantities of earthy carbonates in solution.” 
In i i 
* This Journal, [2], xxviii, 170. 
* Geol. Survey be hana Report, 1853-56, p. 468. 
