548 TEC CLLANMIB TRIE IN, 
it is apparent upon inspection that they can be very largely 
modified and still fall within the limits of the conditions of the 
case. This will perhaps appear more evident in the course of 
the subsequent discussion. In so far as the deductions of 
Arrhenius and the accompanying views of Professor Hégbom * 
fail to definitely postulate operative geological agencies compe- 
tent to produce the requisite variations in the constitution of the 
atmosphere, and to give reasons for believing that such agencies 
were in operation at the times requisite to produce the effects 
assigned them, they fall short of furnishing an ample working 
hypothesis from the geologist’s point of view. This, of course, 
is the function of the geologist rather than the chemist and the 
physicist. Professor Hégbom has made a valuable contribution 
to the general doctrine of consumption and supply. 
To form a good working hypothesis in a geological sense, it 
is furthermore necessary to assign subsidiary agencies working 
in an oscillatory manner correspondent with the oscillations of 
glaciation now so well authenticated by observation. 
Specttic requisites of a working hypothesis.—It is obvious that 
it is necessary at the outset to assign agencies capable of reduc- 
ing the amount of the carbon dioxide of the atmosphere at the 
time of the glaciations. If there were no other glaciation than 
that of the Pleistocene period, and if there were no kindred 
phenomena needing to be elucidated at the same time, it might 
be sufficient to point to the well-known abstraction of carbon 
dioxide from the atmosphere in the formation of limestones and 
carbonaceous deposits, and there rest the case, with the impli- 
cation that further production of limestones and carbonaceous 
deposits would insure further glaciation, and that the permanent 
and final winter of the earth is at hand. A very slight compu- 
tation of the rate at which carbon dioxide is now consumed is 
sufficient to show that an effective depletion of the atmosphere 
is near at hand unless there be sources of supply approximately 
equal to the depletion. But recent depletion touches only the 
1 SVENSK KEMISK TEDSKRIFT, Bd. VI, p. 169 (1894). Quoted in Dr. Arrhenius’s 
paper, p. 269. 
