676 LT 6. CHAMBERLIN, 
until the fundamental conditions were changed or the reaction 
was checked by its own ulterior consequences. The sequences 
may be easily followed. The carbonates of the sea, which had 
been augmented during the epoch of glaciation were now dimin- 
ished and limestone was more actively deposited. The ocean, 
previously fattened in carbonates now became lean. Soalso the 
carbonates themselves, that before were quite plump bicarbon- 
ates, now became degraded to a mixture of normal and acid 
carbonates. In short, the ocean holds less free and feebly-com- 
bined carbon dioxide and the air holds relatively more. As the 
ocean is now estimated to contain from eighteen to twenty-five 
equivalents of atmospheric carbonic acid in the free and feebly- 
combined states, a moderate fluctuation in its content would 
cover the full range of atmospheric variation required to pro- 
duce the climates under discussion, according to Arrhenius. 
On the supposition that the glacial epoch was produced by a 
reduction of the carbonic content of the atmosphere to one half 
the present amount. it would only be necessary for the ocean to 
release -2 or 3 “per cent. of its releasable carbon dioxide to 
restore the atmosphere to the present condition. If the ocean 
gave up 4 or 5 per cent. of its releaseable carbon dioxide 
the climate would be notably milder and more equable than the 
present. Assuming the correctness of Dr. Arrhenius’ conclu- 
sions, it would seem from these considerations that there is 
nothing forced or violent in the supposition that an effective 
interglacial epoch might be brought about by the reactive 
agencies indicated. 
Recrudescence of glaciation.—\f the land area of the globe as 
a whole remained large and high notwithstanding such local 
depressions as have been attributed to the weight of the ice and 
the effects of low temperature; or, more precisely, if the atmos- 
pheric contact area remained large, the conditions for a renewal 
of glaciation would again prevail because the renewal of warm 
temperature, the enrichment of the atmosphere, and the deple- 
tion of the ocean would restore the original action. So soon as 
the ice had retreated from the land, the weathering of the 
