194 



On the Composition of Oceanic 



these constituents agrees sufficiently with that found in X, we 

 take the value for the individual constituents found in it, 

 namely, Fe 2 O 3 , 2-31 per cent., and A1 2 O 3 , 1-14 per cent. 



Manganese. The results obtained in Y and Z agree well, 

 and we take the mean, 32-43 per cent, of MnO. 



Loss on Ignition. The amount of substance taken for this 

 determination was 0*1263 gramme. Recent experiments show 

 that it would lose about three-sevenths of its available oxygen 

 on ignition, and it may therefore be safely concluded that all 

 the CO 2 would be driven off, also all the water, and two-thirds 

 of the available oxygen. We have then 



Moisture removed at 162 C. . . 



C0 2 



Three sevenths available oxygen 

 Balance 



Total loss found 

 We have then the following composition: 



i47 per cent. 



8-87 



1-76 



17-74 



Moisture 

 Carbonic acid 

 Available oxygen 

 MnO 

 Co 2 3 

 CuO 

 Fe 2 3 

 A1 2 3 

 CaO 

 MgO 

 K 2 

 Na 2 

 P 2 6 



Soluble SiO 2 

 Balance of insoluble residue 

 Do., loss on ignition 



1-47 percent. 



8-89 



4-10 



32-43 

 0-025 

 traces 



2-31 per cent. 

 1-14 

 6-83 

 4-08 

 0-47 

 o-43 

 o-57 

 6-32 



27-73 

 5-64 



102-43 



If we assign the CO 2 first to the CaO and then to the MgO, 

 we shall have 



CaCo 3 



MgCO, 



MgO 



12-20 per cent. 

 5-17 

 2-41 



