610 CYRUS F. TOLMAN 
of CO, from the air, but a diminution of from 62 per cent. to 
55 per cent. of the present partial pressure of the gas, and this 
decrease in dissociation caused by the decrease of the partial 
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Frepertion of bicackonate dissociated. 
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Fic. 5 is plotted from Professor Ditmar’s table on page 609. The figures in the 
table are not very constant, but we have taken those that seem to correspond best with 
each other. On the ordinate are the temperatures, and on the abscissa the dissocia- 
tion of the ocean bicarbonate, 2.00 representing fully saturated bicarbonate and 1.00 
normal carbonate, the partial pressure of CO, in the curve (1) is that of the atmos- 
phere as it is at the present time and for curve (2) there is 0 pressure of that gas. 
The two curves have been plotted arbitrarily to cut a 0°, but Professor Ditmar shows 
that there is probably no dissociation at 2° to 3° above zero. 
The line cf connects the two curves at 10° (the temperature of the temperate 
regions Dr. Arrhenius postulates to develop a glacial period) and the points d@ and e 
show the bicarbonate dissociation at a partial pressure of CO. reduced respectively to 
62 and 55 per cent. of its present value. a@ 6 represents the decrease of the dissocia- 
tion of the bicarbonates due to fall of temperature from 15° to 10°) andc¢cd and c e the 
increase of the dissociation due to a decrease of 62 per cent. and of 55 per cent. of the 
present value of the partial pressure of CO, inthe air. a@' 6’ andc'd' andc’ e’ 
represent the same factors for a decrease of temperature from 21° to 16° and the same 
decrease as postulated above in the partial pressure of the CO,. 
pressure of the gas is represented by lines c—d and c-e; so that 
the dissociation will be between the two, that is, viz., from 76 
per cent. to 81 per cent.,z. ¢:, these data show that) the falling 
