238 On the Composition of some Deep-Sea 



evident, from the general agreement of the figures, that the 

 drying process (Table II) has brought the various samples into 

 a very fairly comparable condition. 



Table IV. Determination of the Carbonic Acid. A weighed 

 quantity of the substance was placed in a flask and sulphuric 

 acid added. The carbonic acid was collected in soda-lime tubes, 

 being first dried by passing it through a U tube filled with 

 pumice, moistened with concentrated sulphuric acid, and a tube 

 filled with calcium chloride. 



TABLE V. Determination of the Residue Insoluble in 

 20 per cent. HC1, and of the Total Silica. 



The flask was boiled to expel the gas, and a current of air, 

 free from carbonic acid, was drawn through the apparatus to 

 sweep out all the carbonic acid. 



Near the African coast the amount of CO 2 varies between 

 eight and ten per cent. It increases with distance from the 

 land, being no doubt less masked by land debris. The maximum 

 20-97 of CO 2 (47-17 CaCO 3 ) is found on the Balearic Bank. The 



