the Water of the Lake Elton. 83 



Next to those already named, the water of lake Ourtnia 

 near to Tauris in Persia, appears to be that, of those hitherto 

 analyzed, which contains most salt. According to Dr Marcet 

 its specific gravity is 1.16507, and it contains 22.3 per cent of 

 solid matter, which consists of common salt, sulphate of mag- 

 nesia, and sulphate of soda. 



The similarity between the composition of these waters and that 

 of the ocean and of salt pits is striking. The salts which are 

 found in the waters of the ocean, according to known analyses^ 

 do not differ from those of which Mr Rose has demonstrated the 

 existence in the water of Elton, except that it is generally ad- 

 mitted, after the principles laid down by Murray, that there is 

 in sea water the simultaneous presence of sulphate of soda, and 

 the chlorides of magnesium and calcium ; although in all pro- 

 bability these salts, in extensive solutions, would mutually de- 

 compose each other. We cannot, it is true, determine with cer- 

 tainty in what manner the constituent parts of two salts are 

 combined when these salts are of different solution or insoluble ; 

 but if it be admitted that the salts in the saline solutions are in 

 the state of simple and not double salts, there is the greatest 

 probability that in most cases the salts exist simultaneously in 

 the solution, so that they separate by crystallization, by means 

 of evaporation, at the ordinary temperature, or when it is some- 

 what elevated. That salt which is the least soluble is first sepa- 

 rated. The propositions which Murray adduced in the main- 

 tenance of his hypothesis are not tenable. It cannot b« denied 

 that the sulphate of lime sometimes can maintain itself dissolvoi 

 more easily in saline solutions than in an equal quantity of 

 water; but usually it requires more time for its precipitation. 

 In summer evaporation gradually effects the deposition from 

 salt waters, first of gypsum, then of common salt ; then of sul- 

 phate of magnesia, more or less pure, and sometimes mixed with 

 common salt ; and the chlorite of magnesia, or the most soluble 

 of salts, remains in the sea water. Evaporation never produces 

 sulphate of soda. The brother of the author of tliis article 

 never found any trace of it on the banks of lake Eltou ; and in 

 its waters are only found crystals of the sulphate of magnesia. 



It is true that at different temperatures the combinations 

 partly change in saline solutions in a singular maBQer, but still 

 F 2 * 



