628 president's address, 



creatures constituted as we are. But for the equalising effect of 

 the great ocean surfaces and the evaporation therefrom, with the 

 consequent transport of heat, together with the Ijlanketing effect 

 of the clouds, we should have, over the greater part of the earth's 

 surface, intense heat by day and unendurable cold as soon as the 

 sun had set. 



Another matter of immense importance in the relationship of 

 the ocean and atmosphere is the regulating effect which is 

 exercised by the former on the carbon dioxide content of the 

 latter. This question has been studied by Dr. A. Krogh of 

 Copenhagen.* Briefly put, the conclusions arrived at may be 

 stated thus. The atmosphere over the southern hem.isphere, 

 where ocean surface greatly preponderates, contains 0*026 per 

 cent, of carbon dioxide ; over the northern oceans the proportion 

 is 0-029 per cent., while in Central Europe it rises to 0-033 per 

 cent. The total amount of carbon dioxide contained in the ocean 

 has been calculated to be about 6-55 x 1 0^^ kilograms, existing 

 mainly in readily dissociated salts, while the atmosphere holds 

 about one twenty-seventh of this amount. Any increase in the 

 proportion of carbon dioxide in the atmosphere is checked by the 

 action of the ocean water, which immediately absorbs the greater 

 bulk of it. To increase the proportion of carbon dioxide in the 

 atmosphere from the present 0*03 per cent, to 0*04 per cent, 

 would require in the first place an addition of one-third of the 

 total existing amount, which in itself is an enormous quantity; 

 and further, in order to bring the ocean into equiliJDrium with 

 the air so as to enable the latter to retain the increase, about 

 twice the present amount in the air would have to be provided. 

 Dr. Krogh considers from this standpoint the effect of the world's 

 consumption of coal, which is estimated to pour into the atmos- 

 phere annually about one-thousandth of its present percentage 

 proportion of carbon dioxide. This means that assuming the 

 coal supply to last and consumption to continue at present rate, 



• Meddelelser om Gronland, xxvi. 333-409; Journ. Chem. Soc. London, 

 Ixxxviii., 11, 26 ; Compt. rend. 139, 896-8; Nature, Ixxi. 283. 



