OF SEA-WATER. 231 



This principle, if just, is an important one, as enabling us 

 to determine the state of binary combinations in a saline li- 

 quor. I add, therefore, one other illustration of the reasoning 

 on which it rests. 



Suppose that in a compound saline solution, that is, one 

 containing more than one acid and one base, the acid and the 

 base which have the strongest attraction, are those which are 

 most soluble, or form the most soluble compound ; the solvent 

 power of the liquid operating at the same time, will concur 

 with this, and favour their combination ; and any other acid 

 and base likewise present, will of course, at the same time, 

 combine. But suppose the more powerful attraction to belong 

 to those which form an insoluble compound, the solvent power 

 counteracts this, and prevents the combination. And the 

 more this power is increased, which is done by increasing the 

 quantity of the solvent, the more will this be counteracted. 

 The reverse combinations will therefore be established by the 

 operation of the opposite affinities. Hence, generally speak- 

 ing, in a dilute solution, the binary combinations must be 

 those which form the most soluble compounds, and very pow- 

 erful attractions would be required to counteract this. 



Applying this principle to the composition of sea-water, or 

 rather to the question with regard to the sulphate of soda, and 

 sulphate of magnesia, it is obvious, that the former is to be 

 considered as the original ingredient, and the latter as a pro*, 

 duct of the evaporation ; for muriate of magnesia, and sulphate 

 of soda, are, on the whole, more soluble in water than muriate 

 of soda and sulphate of magnesia. On the same principle it 

 follows, still more unequivocally, that the lime exists in the 

 state of muriate of lime, with a portion of sulphate of soda 

 equivalent to the quantity of sulphate of lime which the eva- 

 poration affords. The salts, therefore, really existing in sea- 

 water, 



