598 
GEOPHYSICS: R. B. SOSMAN 
Proc. N. a. S. 
Section of Meteorology and the atmospheric-electric branch of the 
Section of Terrestrial Magnetism and Electricity; the oceans by the Sec- 
tion of Physical Oceanography; the large land masses by the Section of 
Geodesy; volcanoes as units by the Section of Volcanology. 
The larger geologic units (for example, petrographic provinces) and the 
rocks, considered as geologic units, might be considered to fall within 
the province of geology rather than geophysics, and the same may be said 
of the earth's glaciers and ice-sheets. 
There are certain problems connected with these larger units, how- 
ever, that may be neglected by the Sections mentioned, not from any 
lack of appreciation of the importance of the problems, but solely by 
reason of lack of training and lack of acquaintance on the part of their 
personnel with the technique involved; just as some of the geophysical- 
chemical problems mentioned above may be, relatively, neglected by 
reason of the geophysical-chemist's lack of training in other branches. 
For example, the physics of the flow of a glacier, considered as a unit, 
is not likely to be adequately handled by those trained only in the methods 
of glacial field geology, and it very properly becomes a subject for re- 
search under the present Section. The question of the chemical com- 
position of a particular stratum of the atmosphere and the chemical 
equilibrium obtaining therein, while of great importance to the meteorolo- 
gist, might fail of adequate treatment by an organization numbering 
no chemist on its staff. The distribution of certain rock-forming oxides 
according to "petrographic provinces" may be of primary interest to the 
geologist, yet the physico-chemical basis for that distribution — the ques- 
tion whether it represents an "original heterogeneity" or a result of differ- 
entiation — is a problem for this Section. The flow of rock aggregates 
of varying composition, again a matter of geological interest through being 
concerned in the processes of mountain-building, is a problem for the geo- 
physicist. These examples will serve to indicate that there may be many 
points in which the Section of Geophysical -chemistry may be of direct 
assistance, through researches of its own type, in the work of other Sections. 
B. PROPERTIES OF MATERIALS IN THE INTERIOR OF THE EARTH 
The late G. K. Gilbert has made apt reference^ to the earth's interior 
in these words: "Once it contained the forges of blacksmith gods; or it 
was the birthplace of our race, or the home or prison of disembodied 
spirits * * * * Science now claims exclusive title but holds it 
chiefly for speculative purposes." Upon the Section of Geophysical- 
chemistry more than upon any other will fall the duty of maintaining the 
validity of the title while bringing the property into productive use. 
The outstanding difference of condition to which substances in the 
earth's interior are subjected, as contrasted with substances at the sur- 
face, is the tremendous difference in hydrostatic pressure. Research on 
