190 REVIEWS 
of the carbonic acid in the atmosphere to two thirds of its present 
amount would probably reduce the temperature of the polar regions by 
5° C., and a tripling of the present amount would increase the tem- 
perature there by 18° to 20° C., the temperature of the Cretaceous 
period. A few paragraphs are devoted to discussing the amount of 
carbon dioxide, the cause of its fluctuations. Using a commercial 
simile, he remarks that the exchanges between the CO, consuming 
processes and the CO, yielding processes are carried on with a very 
small capital, and hence they are proportionately rapid, and as a result 
are subject to great and fortuitous changes. New carbonic acid is 
furnished by volcanic activities (Chamberlin, JouURNAL OF GEOLOGY, 
Vol. VI, p. 611), and by meteors bringing it into the upper atmosphere. 
Pursuing his commercial simile he remarks that the reserve fund is in 
the sea. Chamberlin is again quoted on the effect of lime-secreting 
organisms in the sea and as to the chemical condition of the carbonic 
_ acid in the sea. 
Over the first ocean the atmosphere very likely became, as time 
went On, more and more impregnated with carbon dioxide. This is 
supposed to have taken place after the conduction of heat from the 
earth’s interior had ceased to have climatological importance. This 
increase of carbon dioxide is believed to have resulted in the rise of 
temperature which affected the crust of theearth. The temperature of 
the early Cambrian age is hypothetically placed at 20° C., with a rise 
during the period of 10° higher temperature. It is estimated that this 
rise of temperature would cause folds four kilometers in height, if the 
expansion were concentrated so as to have caused rising in any single 
place. Ina similar way mountains are held to have been formed in 
the Carboniferous age. By erosion large amounts of the carbonates 
were carried to the sea, favoring the life of carbonate-secreting animals. 
By the increase of land and of temperature the consumption of CO, 
was increased, resulting in the withdrawal of much of it. Thus the 
cold of the Permian age was brought on. 
The progressive cooling of the surface temperature during the Per- 
mian age is also discussed. A change from 30° to ro’ C. is assumed. 
This brought about a contraction of the outer shell relative to the inner 
kernel of the earth. The computed relative shrinking of the outer 
shell is 12.8 kilometers. This shrinkage brought on extensive crack- 
ing and volcanic activity, and thus led to an increased production of 
carbon dioxide. Thus warm climate again resulted, probably lasting 
