CONSTANCY OP COMPOSITION. 415 



into the sea near the mouth of every large 

 river than elsewhere. 



It is extremely difficult to account for this 

 fact, in the present state of our knowledge 

 on ocean-chemistry. Why are some soluble 

 constituents which ou^ht t<> timl their way into 

 tin- sea, we should say, at least as abundantly 

 as some of the dissolved matters, missed when 

 we come to look for them in analysis? Upon 

 what principle can we account for the enormous 

 presence of the metal sodium in combination, 

 and the comparative absence of potassium, the 

 compounds of which arc equally soluble, or 

 nearly so, with those of the other elements, and 

 much more so than the compounds of magnesium 

 and lime ? Yet, in 1 000 parts of sea- water, the 

 proportion of the chloride of magnesium to that 

 of potassium is as 5 to 1 : even sulphate of lime, 

 a compound comparatively insoluble, is present in 

 equal proportions to chloride of potassium. 



Some suggestions of a solution to the pro- 

 blem of the pretty constant composition of sea- 

 water may be offered. It is to be remembered 

 that, by the laws of chemical combination, a 

 heterogeneous mixture of all kinds of ingre- 

 dients, if left to itself, would ultimately assume 

 a certain definite composition, according to the 

 nature of its contents, and their affinities for 

 one another. Were we, for example, to pour 

 certain quantities of sulphuric, hydrochloric, 



