454 Dr. Marcet's experiments and researches 
chemists to exist in sea-water, I looked for it in the same 
deposit ; but I could not detect the least portion of it by the 
most delicate tests.* 
I next turned my attention to the alkaline salts of sea- 
water; and here I was more fortunate; as I succeeded in 
ascertaining beyond a doubt, that sea-water contains am- 
monia, as it yielded sal ammoniac by evaporation and sub- 
limation. This result was easily obtained. Some of the 
bittern being evaporated to dryness in a retort, and a low 
red heat applied, a white sublimate appeared in the neck of 
the retort, which proved to be muriate of ammonia. The 
mode in which this substance was identified was as follows : 
1. The sublimate was re-dissolved in water, re-evaporated 
to dryness, and again sublimed by the heat of a spirit lamp. 
2. This new sublimate being again dissolved, and solution 
of magnesia and phosphoric acid added, a triple phosphate 
was formed. 
3. On adding caustic potash to the solution, and bringing 
the mouth of a phial containing muriatic acid close to the 
vessel, abundant white fumes appeared. 
4. The sublimate gave precipitates both with muriate of 
platina and nitrate of silver.-f 
Sulphate of soda having been mentioned by many che- 
mists, as one of the constituents of sea-water, I endeavoured 
to ascertain, whether or not it existed in it. But all attempts 
* Namely, solution of the mass in dilute muriatic acid ; precipitation of the 
lime, and addition of phosphate of ammonia to the filtered liquor. 
+ As it did not enter into my plan, on this occasion, to turn my attention to the 
estimation of proportions or precise quantities, I have not attempted to estimate 
exactly the proportion which ammonia bears to the other ingredients of sea-water; 
but as its presence can easily be shown in 100 grains of the bitter salts, its quantity 
cannot be extremely minute. 
