1 8 An Analysis of Sea-water ; 



stated as ingredients, had been obtained from some peculiarity 

 in the process by which their reciprocal action, and consequent 

 transition into muriate of soda and sulphate of lime had been 

 prevented ; and that in the common method of evaporation 

 they are not obtained, because this mutual decomposition takes 

 place. It appears, however, that the results by Lavoisier's me- 

 thod are different from those he stated, and are such as pre- 

 clude this view. No muriate of lime is obtained, and sulphate 

 of lime is obtained in considerable quantity; of course, the sul- 

 phate of soda, which is also found, cannot be considered as be- 

 ing procured, in conse(|uence of its decomposition by muriate 

 of lime being prevented by any peculiarity in the process, and 

 must therefore be ascribed to some other cause. 



Besides the peculiarity in this analysis of sulphate of soda, 

 there is another singularity in the result, that little sulphate of 

 magnesia is procured. This salt, it is well known, is extracted 

 in considerable (juantity by tiie common process of evaporation 

 of sea-water on a large scale, being obtained by boiling down 

 the bittern, while, by this method, little or no sulphate of soda is 

 obtained. 



The products of this analysis are thus so different from those 

 usually assigned, and so different from those known to be af- 

 forded by the usual process of evaporation, that it became de- 

 sirable to perform the analysis in the common mode, so as to 

 ascertain the actual results of it with precision, with a view to 

 determine on what these differences depend. This I accordingly 

 executed. 



A. Four pints of the same sea-water were submitted to eva- 

 poration in a sand-bath, and after the crystallization of the mu- 

 riate of soda commenced, the liquor was poured off at intervals 

 from the salt deposited, and further evaporated. This was con- 

 tinued as long as it appeared to afford no other salt on cooling 

 than muriate of soda. The latter products of this salt were less 

 pure than the first, being deliquescent on exposure to a dry at- 

 mosphere ; they were therefore redissolved in water ; by evapo- 

 ration, the greater part was obtained crystallized, in a purer 

 state, and v/as added to the other ; and the small portion of 

 residual liquor was added to the residual liquor of the evaporated 

 sea-water. 



B. By further evaporation, this liquor afforded crystals in 

 slender prisms, which were permanent in the air, and which were 

 found to be sulphate of magnesia; by repeated evaporations, 

 successive crystallizations of this kind were produced, (small 

 portions of muriate of soda being also obtained, which, afier 

 being washed, were added to the salt A) ; the products of the 

 first crystallizations were nearly pure ; those of the latter cry- 

 stallizations 



