456 Dr. Marcet’s experiments and researches , &c. 
potash and magnesia ; a salt so easily analyzed, that it would 
be quite superfluous to relate the particulars of the process. 
It now remained to be ascertained, whether potash might 
not also exist in sea- water in the state of muriate of potash, 
or of triple muriate of potash and magnesia. That a con- 
siderable quantity of potash remains in the bittern, even 
after the separation of the triple sulphate, is easily ascer- 
tained ; and by careful evaporation it may be made to crys- 
tallize as a triple salt in rhombic crystals ; but the consti- 
tution of this salt is so delicate, that it is liable to be sepa- 
rated into muriate of potash and muriate of magnesia by 
water alone ; and it is with certainty decomposed by alcohol, 
which takes up the magnesian muriate, and leaves the other 
undissolved. 
From the foregoing observations and experiments it may, 
therefore, be inferred, 
1st. That there is no mercury, or mercurial salt, in the 
waters of the ocean. 
2dly. That sea-water contains no nitrates. 
3dly. That it contains sal ammoniac. 
4thly. That it holds carbonate of lime in solution. 
5thly. That it contains no muriate of lime. 
6thly. That it contains a triple sulphate of magnesia and 
potash. 
Some of these circumstances will, of course, require that 
former analyses of sea-water, and my own in particular, 
should be corrected and revised ; but this I shall not attempt 
to do, until I have obtained farther, and still more precise 
information on the subject. 
Harley Street, 20 June, 1822 . 
