OF SEA-WATER. 209 



produced by the mutual decomposition of sulphate of soda and 

 muriate of lime. But it is also possible, that this decomposi- 

 tion might not be complete. I had formerly found, indeed, 

 that when a liquor containing these two salts is evaporated, 

 their decomposition is not entirely effected * ; it seemed pos- 

 sible, therefore, that portions of both might remain undecom- 

 posed in Lavoisier's process ; the alcohol applied to the solid 

 matter would remove the muriate of lime, and thus the sul- 

 phate of soda would remain. To elucidate the whole subject, 

 therefore, it seemed best to repeat Lavoisier's analysis as he 

 had performed it, and ascertain the actual results. 



A. Four pints of sea-water of the Frith of Forth, taken up 

 near Leith, at a distance from any fresh water, were evapora- 

 ted by the heat of a sand-bath ; the evaporation being continu- 

 ed until a pellicle of salt formed on the boiling liquor. A pre- 

 cipitate subsided during the boiling, which being washed, 

 weighed when dry 25 grains. 



B. The liquor was evaporated to dryness, and the saline mass 

 was dried thoroughly by a continued heat of about 150° ; it 

 weighed 1025 grains. To separate the salts composing it, it 

 was submitted to the action of alcohol. About 4 ounces of alco- 

 hol of the specific gravity of 840 were poured upon it in a 

 bottle, and allowed to remain over it for 12 hours, being occa- 

 sionally agitated ; and when poured off an ounce of the same 

 alcohol was added, and after frequent agitation, and being kept 

 over it for some hours, was poured off, and added to the for- 

 mer. 



C. The residuum, when dried, weighed 890 grains; 135 

 grains had therefore been abstracted, consisting chiefly of earthy 

 muriates. 



Vol. VIII. P. I. D d D. The 



* Transactions, Vol. vii p. 475. 



