670 T. C. CHAMBERLIN 
Now the task assigned this remarkable combination of agen- 
cies is not a formidable one. If we take the largest of the cur- 
rent estimates of the present atmospheric content of carbon 
dioxide, viz. .06 per cent. by weight (comparable to .0o4 per 
cent. by volume), the mid-Tertiary atmosphere should have con- 
tained .15 per cent. to’.18 per cent. of carbon dioxide, and that 
of the glacial period .03 per cent., following Dr. Arrhenius’ esti- 
mates. That is to say, for the reduction of the carbon dioxide 
of the Tertiary atmosphere from the assigned .15 per cent. or 
-18 per cent. to the assigned .03 per cent. of the glacial period, 
we have an estimated increase of land area of 47 per cent., and 
an increase of elevation of 100 per cent. or 200 per cent., and 
perhaps more. To produce the present amelioration we have a 
falling off of about one half in each of these items. 
Numerical data, which will be given later, indicate that 
something like 5,4) of the carbonic acid of the air is now taken 
out annually. If the same amount is returned, the constitutional 
status is preserved. But if the foregoing agencies that codper- 
ated in late Pliocene and early Pleistocene times to disturb the 
balance between removal and return were effective to no more 
than 10 per cent. of the total rate, it would have been capable of 
reducing the assigned mid-Tertiary content of .18 per cent. 
carbonic acid to the assigned glacial content of .03 per cent. in 
50,000 years. It is not, of course, supposed that the rate would 
be constant as the state of enrichment changed, and note of this 
will be taken later, but the computation serves to show how 
effective a disturbance in’ the relative. rates jot jsupplygiand 
removal becomes when such action bears so high a ratio to the 
total mass of carbon dioxide in the air. It may also serve to 
show that the hypothesis is assigning agencies whose supposable 
quantitative competency is abundantly adequate to the results 
imputed to them. 
ASSIGNED CAUSES OF GLACIAL OSCILLATION 
It has been already noted ‘repeatedly that the assigned 
causes of glaciation are self-accelerating in certain significant 
