335 



gases. At the same time I had in view the determination of 

 the tensions in the surface-water of the sea and especially ascer- 

 taining as to whether the carbonic acid was really in equilibrium 

 with the atmosphere. 



The results 1 attained with regard to the last-mentioned 

 question appeared to me to be so interesting that I devoted 

 most of my time to it during my stay in Greenland, and I 

 have since my return pursued it further. 



\n the present paper I intend to give: 



I. A brief account of the methods originally applied and 

 the modifications, which I have introduced, stating more fully 

 the kinds of apparatus and details of method, which F have 

 found most suitable. 



П. The physico-chemical theory of carbonic acid in sea- 

 water and freshwater and the relations between the quantity 

 and the tension of the gas in ocean-water. 



in. An account of my determinations of tension in Green- 

 land and Danish freshwaters, in the Baltic and in^ the Ocean, 

 together with the hydrographical , biological and geological 

 considerations to which they give rise ^). 



The influence of the CO^- tension of the ocean on the composition of 

 the atmosphere will be discussed in a separate paper. 



