on the saline contents of sea-water. 451 
which Rouelle stated that the quick-silver was usually found. 
This sediment being carefully dried, and heated to redness in 
a coated retort, a white sublimate arose, and condensed on 
the neck of the retort ; but this sublimate proved to be mu- 
riate of ammonia, and did not contain the smallest portion of 
corrosive sublimate or other mercurial salt. This sal-am- 
moniac, though evidently formed during the distillation from 
the vegetable and animal matter contained in the sediment, 
suggested to me the idea of looking for ammonia amongst 
the contents of sea-water. 
I now submitted some Sel de Gabelle, which I had procured 
from Calais for the purpose, to similar experiments, and the 
sediment, also, was carefully examined. The result was 
essentially the same as with the bay-salt. After adding nitric 
acid to the salt, the heat was gradually pushed to redness ; 
and when all the moisture was evaporated, a white sublimate 
appeared, as in the former case, which, in this instance, proved 
to consist almost entirely of nitrate of soda ; but always with- 
out the least particle of mercurial salt, and without any mu- 
riate of ammonia.* 
I therefore think myself justified in concluding that the 
mercury, which other chemists have detected in sea-salt or 
its products, must have been introduced there from some local 
or accidental circumstances. 
In experiments upon sea-salt, or in general upon the saline 
contents of the sea, it is obvious that, in order to exclude 
sources of error, it is necessary to operate upon pure sea- 
* In the former experiment the sublimate was principally muriate of soda, owing, 
no doubt, to the decomposition having been less complete, and the operation less 
gradually conducted than in the latter experiment. 
