REVIEWS 
Two Gas Collections from Mauna Loa. By E. S. SHEPHERD. 
Bull. Hawatian Observatory, Vol. XIII, No. 5, May, 1920. 
This is a brief report by Dr. Shepherd of the Carnegie Geophysical 
Laboratory at Washington on two gas samples collected by Dr. T. A. 
Jaggar, Jr. The samples were taken near the edge of a flow of incan- 
descent rough pohoehoe lava on the south slope of Mauna Loa. The 
gases were collected in vacuum tubes from a depth of 2 feet in a 2-inch 
crack in the lava surface. The lava at a depth of 3 feet was glowing and 
the estimated temperature at the point of collection was 300° C. 
A condensation of water within the tube was noted immediately 
upon collection. The analyses showed that about 70 per cent by volume 
of the gas (computed at 1200° C. and 760 mm. pressure) was water, in 
which respect the gases closely resemble those of Kilauea. About 
16 per cent was nitrogen and the remainder mainly SO,, SO, and CO.. 
The water cannot be explained as the result of oxidation of hydrogen 
by admixed air, as is shown by the nitrogen percentage. Ii all the 
nitrogen were assumed to come from admixed air, the oxygen in such 
a quantity of air would be insufficient to account for the observed water. 
The evidence of these samples accords with the classic work of Day 
and Shepherd at Kilauea in demonstrating the abundant presence of 
water in certain volcanic gases. 
The gases of Mauna Loa show a high degree of oxidation, i.e., they 
have been almost completely burned. In general, they show a high 
degree of similarity to the Kilauea gases although the latter are rather 
variable. Especially noteworthy at Mauna Loa is the abundance of 
5O,—2 to 8 per cent. 
E. S. BASTIN 
The Geology and Ore Deposits of the Virgilina District of Virginia 
and North Carolina. By Francis BAKER LANEY. Virginia 
Geological Survey, University of Virginia. (Prepared jointly 
by the Virginia Geological Survey and the North Carolina 
Geological and Economic Survey.) 10917. Pp. 176. 
The Virgilina district which lies partly in Virginia and partly in 
North Carolina is one of the copper districts in the eastern United States 
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