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to a greater extent than any of the other gases. The results of his 
investigations leads Professor Arrhenius to the conclusion that 
if the CO2 is increased 2.5 to 3 times its present value, the tem- 
perature in the Arctic regions must rise 8 to 9 degrees C and pro- 
duce a climate as mild as that of the Eocene period. A decrease 
of .65 or .55 of its present value would cause a fall of from 4 to 
5 degrees C and produce a glacial climate. 
Professor Chamberlin took up the subject at this point 
endeavoring to show geological relations that might produce 
such atmospheric changes. It is he says an attempt to frame a 
working hypothesis of the cause of glacial periods on an atmos- 
‘pheric basis. 
Along with the fact that the increase of COz2 in the atmos- 
phere tends to raise the temperature and a decrease to lower it, 
it has been shown that the increase of CO2 tends to equalize the 
temperature while a decrease tends to intensify the variations or 
differences in temperature between (1) low and high latitudes, 
(2)day and night, (3) the seasons, (4) land and sea, (5) the 
upper and lower portions of the atmosphere. Hence, a decrease 
would lead to (1) greater local heat as well as greater local cold, 
(2) to greater local dryness as well as greater local moisture, 
(3) to more intense movements of the atmosphere in the effort 
to restore equilibrium, (4) to lower the average temperature. 
On the assumption that the increase and decrease of CO2 in 
the atmosphere causes corresponding change in the temperature 
along with corresponding equalization or intensification of the 
variations it next becomes necessary to find the agencies that can 
produce the increase or decrease. The agencies of both increase 
and decrease may be divided into permanent and the temporary. 
The permanent loss consists (1) in the carbonation of the 
silicates, that is a change of the silicates of the igneous rocks to 
the carbonates of the sedimentary series. This is accompanied 
by the formation of oxides, sulfates, phosphates, etc., but that 
does not change the fact that large quantities of CO2 are used 
up in the formation of the limestones and the dolomites. (2) 
By plants and the fixation of large quantities of carbon in the 
