CARBON DIOXIDE OF THE OCEAN 615 
depth the equatorial waters have average temperature of 12°. 
Therefore, this will be the limit of the waters of the belt that 
had temperatures of 2° to 7° during maximum glaciation. Above 
K are the waters which now have temperatures above 12°, and 
during glaciation temperatures above 7°. 
To get a correct conception of this section of the ocean 
waters from pole to pole, we must multiply the length given 
here by 550. 
The portion of the ocean below 1500 fathoms is already 
down to the limiting temperature; therefore, its carbon dioxide 
content is not subject to fluctuations. This leaves out of the 18 
5) 
atmospheres of ‘free’? CO, about 13 atmospheres above the 
1500 fathom line. 
The volume of these waters is divided as follows: 
go° to 60° N. and S. latitudes, - - - 11% 
60> tor3'7: sc gs = = = 2 
B77 to 6° “ ““ x = 5 65 
Now, the volume of water included between adc and efh 
is considerably over one half that above the 1500-fathom line, 
or it holds about seven atmospheres CO,, and a change of tem- 
perature from 7° to 2° represents a change in the dissociation 
otsthe bicarbonates. from 1.9 to 2:00 (see Pig. 5; p. 610): or 
more than a 10 per cent. increase in the ‘free’ CO,. . Therefore, 
this advance of the cold waters upward and toward the equator 
represents an increased capacity of the ocean for CO,, equal 
to about seven tenths that of the present atmosphere. 
The waters above mun represent those which now have a 
temperature above 12° C. (we neglect the warm surface waters 
now spread far poleward by the warm currents), and it 1S in tne 
warmer of these waters that the diminishing partial pressure of 
the CO, may cause a loss of CO, from the ocean. 
Now this volume represented by m £m is considerably less 
than 2 per cent. of the volume above the 1500 fathoms line, so 
that for a limiting case if ad? the second equivalent were lost in 
these waters, instead of only at most a small portion of it, it would 
amount to less than one third that gained by the advance of the 
