298 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, No. 13 
The first paper on Liquid and solid hydrogen was presented by Dr. C. W. 
Kanout. The paper was discussed by Messrs. Heryn, Pawnine, Lirrue- 
HALES, HAWKESWORTH, CHANEY, amd HuMpHReEys. 
Author’s abstract: Liquid hydrogen was first obtained by Dewar in Eng- 
land about 25 years ago, and since then it has been produced in several 
laboratories. Although the method employed is fairly simple in theory, 
there have been some practical difficulties involved. The purpose of the 
work at the Bureau of Standards has been, first to make it possible to obtain 
readily at the bureau fairly large quantities of liquid hyrogen for experimental 
purposes, and, second, to study the difficulties of the process in order to make 
it easier for other laboratories to produce the liquid. 
The principal difficulty has resulted from the influence of small quantities 
of air in the hydrogen. The air is frozen in the hydrogen expansion valve 
and soon clogs it. A proportion of air too small to be found by ordinary 
methods of gas analysis may still be sufficient to produce clogging. However 
a new method of determining very small quantities of nitrogen, the most 
troublesome impurity, in hydrogen has been found, and this has greatly 
facilitated the investigation and elimination of sources of contamination. 
~The hydrogen employed is generated electrolytically in the laboratory. 
The liquefier in use produces two liters of liquid per hour and little difficulty 
is now experienced in its operation. 
Solid hydrogen can be obtained by evaporating the liquid in a partial 
vacuum produced by a pump of sufficiently large capacity, and as the vapor 
pressure at the freezing point is relatively high, this operation is not difficult. 
Liquid hydrogen was exhibited at the meeting and with it air from the 
room was liquefied and frozen. ! 
President Wuirr made announcement of the meetings of the American 
Geophysical Union to be held at the Administration Building of the Carnegie 
Institution of Washington on April 17 to 19. 
Captain N. H. Heck presented a paper on The relation of seismology to 
geodesy and tides. The paper was illustrated with lantern slides, and was 
discussed by Messrs. Humpnreys, L. H. Apams, and Bowtr. 
Author’s abstract: A brief introductory statement shows what is being 
done in the United States in the study of Seismology, and the relation of 
the Coast and Geodetic Survey, which is doing the principal work in geodesy 
and tides, to this subject. 
The need for better instruments, operation, and time control is pointed 
out. The important cooperative earthquake investigation in California 
by the Carnegie Institution of Washington, the California Universities, the 
Geological Survey, and the Coast and Geodetic Survey has brought out the 
necessity for precise triangulation and levels in seismological work, to deter- 
mine whether or not surface shifts have occurred. Observations in Japan 
and elsewhere show clearly that such work should be carried on in earth- 
quake regions. " 
The possibility of such shifts along the coasts, due to submarine earth- 
quakes, makes the observation of such earthquakes of special importance. 
The magnetic observatories of the United States, though placed entirely 
with regard to magnetic work, are exceptionally well located for the obser- 
vation of submarine earthquakes, four of them being in regions where major 
earthquakes have occurred. 
Submarine earthquakes are the cause of the so-called tidal waves, de- 
structive nearby, and often causing long continued fluctuations at a dis- 
tance. Tidal records of the Chilean earthquake tide and of the recent 
