512 THE DEPTHS OF THE SEA. [chap. x. 



the samples, as shown of the determinations of organic 

 carbon and organic nitrogen, and the proportion of organic 

 carbon to organic nitrogen. For the purposes of comparison, I 

 have appended the results of analyses of Thames-water and of 

 the water of Loch Katrine, the former representing probably 

 about a fair average of the proportion of organic nitrogen 

 reaching the sea in the rivers of this country, but being pre- 

 sumably considerably greater than that contributed by rivers in 

 other parts of the world. If this be so, it follows either that 

 soluble nitrogenous organic matter is being generated from inor- 

 ganic materials in the sea, or that this matter is undergoing con- 

 centration by the evaporation of the ocean, — the rivers and 

 streams continually furnishing additional quantities whilst the 

 water evaporated takes none away. 



The amounts of carbonate of lime given in the table are ob- 

 tained by adding the number three (representing the solubility of 

 carbonate of lime in pure water) to the temporary hardness which 

 denotes the carbonate of lime thrown down on boiling. As the 

 determination of temporary hardness in water containing so 

 much saline matter is not very accurate, the numbers in the 

 columns headed ' Temporary Hardness ' and ' Carbonate of Lime ' 

 must only be regarded as rough approximations to the truth ; 

 moreover, a small proportion of carbonate of magnesia is mixed 

 with the carbonate of lime and estimated with it. 



In all their peculiar features these analytical results agree 

 with those which I have previously obtained from numerous 

 samples of sea-water collected by myself off Worthing and 

 Hastings. 



Yours very truly, 



E. Fkankland. 



