455 
on the saline contents of sea-water. 
to detect this salt in the bittern by crystallization were fruit- 
less, though great pains were taken for that purpose ; and I 
feel the more confident that there is no sulphate of soda in 
sea-water, as the presence of this salt, in any but the most 
minute quantities, would be quite incompatible with our know- 
ledge of chemical affinities. For since there are, co-existing 
in sea-water, muriate of soda and sulphate of magnesia, it is 
evident that sulphate of soda would decompose muriate of 
magnesia, which salt is known to be in sea-water. And again 
we know, that sea-water contains sulphate of lime and muriate 
of soda ; therefore it cannot contain sulphate of soda ; for in 
that case we should have muriate of lime, W'hich I have shown 
to be contrary to fact. 
The last circumstance which I shall at present notice, re- 
lates to the state in which potash exists in sea-water.* Potash 
is found, by its appropriate re-agents, principally in the bittern ; 
but it is found also among the salts which are separated from 
it, especially in the latter period of crystallization. By farther 
and repeated evaporation of the bittern, and successive separa- 
tion of the mother water remaining after the removal of the 
crystals formed, various distinct crystals were obtained pos- 
sessing their characteristic form, namely, prismatic sulphate 
of magnesia, cubic and star-shaped muriate of soda, and 
rhombic crystals, quite different from either of the other salts. 
These crystals, which were evidently portions of an oblique 
rhombic prism, being carefully separated and washed with 
water and alcohol, proved to be a triple salt of sulphate of 
* It will be recollected, that the presence of potash in sea-water, though an- 
nounced by myself in the paper on sea-water to which I have before alluded, was 
Dr. Wollaston’s discovery. I have likewise to mention, that the above experi- 
ments respecting the state in which it exists, were either made by him or at his 
suggestion. 
