on the Saline Contenis of Sea- Water, 439 



certain, whether or not it existed in it. But all attempts to 

 detect this salt in the bittern by crystallization were fruitless, 

 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 quan- 

 tities, would be quite incompatible with our knowledge of 

 chemical affinities. For siiice there are, co-existing in sea- 

 watei', 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, which I have shown to be 

 contrary to fact. 



The last circumstance which I shall at present notice, re- 

 lates to the state m 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 further 

 and repeated evaporation of the bittern, and successive sepa- 

 ration of the mother-water remaining after the removal of the 

 crystals formed, various distinct crystals were obtained pos- 

 sessing their characteristic form, nameh', 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 

 potash and magnesia ; a salt so easily analysed, 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 ascertained ; and 

 by careful evaporation it may be made to crystallize as a triple 

 salt in rhombic crystals ; but the constitution of this salt is so 

 delicate, that it is liable to be separated into muriate of potash 

 and muriate of magnesia by water alone ; and it is with cer- 

 tainty decomposed by alcohol, which takes up the magnesian 

 muriate, and leaves the other undissolved. 



* It will be recollected, that the presence of potash in sea-water, though 

 announced by myself in the paper on sea-water to which I have before al- 

 luded, was Dr.Wollaeton's discovery. I have likewise to mention, that the 

 above experiments respecting the state in which it exists, were either luade 

 hy him or at his suggestion. 



From 



