THE GASES IN ROCKS? 
R. T. CHAMBERLIN 
The University of Chicago 
It has been known for a long time from microscopic studies that 
some minerals inclose minute cavities which contain both liquid and 
gaseous matter. For a much shorter period it has been known that 
various igneous rocks, when exposed to red heat in a vacuum, evolve 
several times their volume of gas, and that this gas is of quite variable 
composition. Since these gases occur in proportions entirely different 
from those of the constituents of the air, it has not seemed probable 
that they were derived directly from our present atmosphere, unless 
the rocks manifest some power of selective absorption not now under- 
stood. The apparent difficulties involved in this conception have 
suggested that some earlier atmosphere was rich in those gases. This - 
involves a hypothesis relative to the changes through which the atmos- 
phere has passed, and leads on to a theory of its origin and that of 
the earth itself. An alternative hypothesis regards these gases, not 
as the products absorbed by a molten earth from its surrounding 
gaseous envelope, but as entrapped in the body of the earth during 
its supposed accretion, and hence as a source from which acces- 
sions to our present atmosphere might be derived. <A_ study 
of the gases in the rocks has seemed, therefore, to give promise of 
results of some value to atmospheric. problems and, perhaps, to those 
of cosmogony. Because of this, it has appeared advisable to deter- 
mine more widely the range and the distribution of these gases, their 
relations to other geologic phenomena, and the states in which the 
gases, or gas-producing substances, exist in the rocks. 
THE ANALYSES CLASSIFIED 
In these studies the gases were extracted for analysis by heating 
the powdered rock material to redness in a vacuum and pumping off 
1 This paper presents in a brief form some of the results discussed at greater 
length in “‘The Gases in Rocks,” Publication No. 106 of the Carnegie Institution of 
Washington. For a detailed description of the analyses, a discussion of the chemical 
aspects of the problem, and an outline of the work previously done in this field, recourse 
must be had to the original paper. 
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