Voi^. 6, 1920 
GEOPHYSICS: H. S. WASHINGTON 
591 
minerals is one of the utmost importance to some phases of the study 
of volcanoes. Of similar importance is the study of the gases contained 
in volcanic and other igneous rocks, as well as of the gases given off by 
volcanoes in activity, with experimental laboratory study of their equi- 
libria and possible interreactions. As is well known, all these, and similar 
problems form objects of investigations carried out at the Carnegie 
Geophysical Laboratory. 
The formation of volcanic salts and other fumarole products, as well 
as the action of the fumaroles themselves, their temperatures and other 
characters, also come under the domain of geophysical-chemistry. Among 
other subjects may be mentioned: the determination of the actual tem- 
peratures of lavas of different compositions, and the thermal and luminous 
radiations of molten lava; the study of volcanic flames with the spectro- 
scope; the melting-points or intervals of solidified lavas, especially as com- 
pared with the temperatures at which they issue; the expansion of the 
included gases as a factor in producing the various types of lava texture, 
such as the scorias and pumices; the formation of jointing through cool- 
ing, whether on a large or a small scale; the specific heats, compressi- 
bilities, thermal expansion coefficients, densities, and other physical or 
physico-chemical data, of rocks and rock minerals; the viscosity of lavas 
and its relation to temperature, chemical composition, and gas content. 
Many others suggest themselves, but the possible list is too long for 
enumeration here. 
VOLCANOLOGY AND MISCELLANEOUS SCIENCES 
In a previous section we have already touched on the connection with 
engineering in the possible utilization of volcanic heat. There may also 
be mentioned the application of engineering to the prevention of destruc- 
tion by lava flows or eruption-bred torrents of mud on the flanks of 
volcanoes. 
In connection with botany and related sciences there may be mentioned 
the subject of the effect of volcanic gases on different kinds of vegetation, 
a study that is being made at Vesuvius > The problems of the reclama- 
tion for agriculture of areas covered with recent lava flows or thick de- 
posits of volcanic ashes or dust is also one of great practical importance in 
many volcanic regions. It may be mentioned, in this connection, that the 
recent expedition to Katmai, under Dr. Griggs, was undertaken, primarily 
for the study of the vegetation of the region devastated by the eruption. 
Though the conditions are almost diametrically opposed, the main object 
was like that of the study of the Salton Sea flora by the Carnegie Desert 
Laboratory. Study of methods for the commercial extraction of potash- 
from certain types of lava, as those of the Italian volcanoes, is also a 
matter of possibly great importance for agriculture in the future. 
Finally, to leave the earth, the suggestion is made that some knowl- 
