JAN. 4, 1923 PROCEEDINGS: WASHINGTON ACADEMY OF SCIENCES 13 
PROCEEDINGS OF THE ACADEMY AND AFFILIATED 
SOCIETIES 
WASHINGTON ACADEMY OF SCIENCES 
166TH MEETING 
The 166th meeting of the AcapEemy was held jointly with the Chemical 
Society of Washington (Local Section of the American Chemical Society) 
in the Assembly Hall of the Cosmos Club, the evening of Thursday, March 16, 
1922. Dr. R. B. Moorg, Chief Chemist, Bureau of Mines; delivered an 
illustrated lecture, entitled, The rare gases: Their history, properties, and uses. 
The lecturer gave first an outline of the history of the discovery of the 
rare gases. The first one, argon, was discovered jointly by Ramsay and 
Raleigh, due to an investigation by them of the difference in the density of 
nitrogen obtained from the air and from other sources. The discovery of 
helium was based on the observation of Dr. W. F. Hillebrand in 1888 that 
certain uranium minerals on heating or on solution in acid gave off gases, a 
considerable proportion of which appeared to be nitrogen. Ramsay showed 
that the residual gas, instead of being pure nitrogen, contained helium. Neon, 
krypton, and xenon were discovered by Ramsay and Travers through the 
fractionation of liquid air. 
The physical properties of the elements were described, and their occur- 
rence in nature fully gone into. Of special interest is the occurrence of 
helium not only in certain minerals and in the gases from springs, but also 
in natural gases from certain localities in the United States. The gases from 
some of the springs in France are particularly rich in helium, going as high 
as 10 per cent by volume. On the other hand, whereas the per cent in 
natural gas is not nearly so large (the maximum amount being about 1.8 per 
cent helium), the total volume of helium available is immense in proportion 
to that obtained from springs. 
The origin of the rare gases was discussed, particularly the probable origin 
of helium: The latter may either come from radioactive changes or, assum- 
ing the Nebular hypothesis, from the atmosphere of the sun or the disinte- 
gration of supposedly non-radioactive elements, the alpha particle having a 
velocity below what is required for the ionization of gases. 
The commercial production of helium, argon, and neon was described, 
and the Government project for the production of helium from natural gas 
for use in dirigibles and balloons was gone into in some detail. The early 
work in connection with the three experimental plants during the war and 
the development of the project since that time were fully described. 
167TH MEETING 
The 167th meeting of the AcapEmy was held jointly with the Philosophical 
Society of Washington and the Chemical Society of Washington in the 
. Assembly Hall of the National Museum, the evening of Wednesday, March 29, 
1922. Dr. F. W. Aston, of Cambridge University, England, delivered an 
illustrated address on Isotopes and the structure of the atom. 
The experimental study of radioactive elements led to the new and revolu- 
tionary conclusion that elements might exist which were chemically identical 
but which differed in radioactive properties and even in atomic weight. This 
idea has been strongly supported by the results of positive ray analysis, 
