The Chemical Theory of the Tension. 



The chemistry of the carbonic acid in seawater appears 

 to have been very puzzling to the earlier investigators, and the 

 problem has only been solved in comparatively recent years, 

 through the labours of Tornöe^), Dittmar^) and, especially, 

 Hamberg^). Independently of these authors. Schloesing*) appears 

 to have had a clear and correct conception of it. 



When the several mineral components of seawater are 

 carefully determined it is seen that the bases (Ncio 0, Ca 0, 

 MgO) are slightly in excess of the acids (HCl, H^SO^), so 

 that the water is in reality alkaline. This was discovered by 

 DiTTMAR (p. 20), and, at about the same time, Tornöe directly 

 observed the alkaline reaction on litmus and rosolic acid. Tornöe 

 found out, further, that the surplus alkali is combined with 

 carbonic acid, and he devised an excellent method for the 

 quantitative determination of the carbonic acid and the alkalinity, 

 viz. to acidify a portion of water with normal sulphuric acid, 

 to boil off the carbonic acid in a suitable apparatus, collecting 

 the separated gas in normal baryta-water. After the boiling 

 the quantity of carbonic acid is titrated in the baryta-solution. 



') The Norwegian North-Atlantic Ex2}edition 1876—78. Chemistry. 2. 

 On the Carbonic Acid in the Sea-Water by H. Tornoe. 



') Challenger Reports. Physics and Chemistry I. Report on the Com- 

 position of the Ocean-Water by W. Dittmar. 



') Om koisyran i hafsvattnet af Axel Hamberg. Bihang K. SvensJca 

 Vet.-Akad. Handlingar Bd. 10 Nr. 13. 1885. p. 31— .50. 



■*) Sur la constance de la proportion d'acide carbonique dans l'air par 

 Th. Schloesinü. Comptes rendus 1880. T. 90. p. 1410. 



