FEB. 4, 1923 PROCEEDINGS: PHILOSOPHICAL SOCIETY 45 
would move inwards nearly two meters (more exactly 185 centimeters, or 6.06 
feet). 
It was pointed out that this degree of compressibility finds important 
applications in geology, since it indicates that crustal subsidence and elevation 
amounting to hundreds, if not thousands, of meters may be due to variations 
in surface loads. 
Reference was made to an earlier investigation by the author of ‘The 
effects of secular cooling and meteoric dust on the length of the terrestrial 
day”’ (Astronomical Journal, No. 502, July, 1901), in order to show that 
neglect of the compressibility of the earth in that investigation led to no 
sensible error. 
871ST MEETING 
The 871st meeting was held in the Cosmos Club auditorium, Saturday, 
November 4. It was called to order by President CrirrENDEN at 8:35 p.m., 
with 47 persons in attendance. 
A paper by F. Wenner, Nina Forman, and A. R. LinpBERG on The 
variation of metallic conductivity with electrostatic charge was presented by Mr. 
Wenner. It was discussed by Mr. TuckERMAN. 
Author’s Abstract: In the spring of 1921, Professor H. A. Perkins presented 
a paper to the American Physical Society in which he stated that a simple 
conception of metallic conduction based on moving electrons seemed to 
justify the assumption that a negative charge should increase the conduc- 
tivity of a circuit and a positive charge should decrease it. He tested this 
assumption as follows: 
A primary coil was wound upon a glass cylinder inside of which fitted 
a similarly wound secondary coil. The primary was excited through a 60 
cycle circuit while the secondary circuit carefully insulated throughout 
included a moving coil galvanometer. At the same time the secondary 
circuit was given an alternating charge from one terminal of a high tension 
transformer, the other terminal being grounded. In operation the gal- 
vanometer was not affected either by the charging potential alone or by the 
induced alternating current alone. If, however, the induced current and 
the charging potential were both present, alarge deflection of the galvanometer 
was observed. This phenomenon behaved in a perfectly regular manner and 
reversed if the phase of the charging E. M. F. were reversed by interchanging 
the terminals of the transformer. 
An effect such as that just described would be of sufficient importance to 
require careful investigation, and some modification of our notions of metallic 
conduction. However, on repeating the experiment using reasonable pre- 
cautions to prevent disturbing influences we observed no change in the 
deflection of the galvanometer on changing the phase between the current 
in and the potential of the test circuit. The arrangement of the circuit was 
such that on the basis of the explanation given the effect should have been 
larger than in the original experiment while the sensitivity of the galvanom- 
eter was such that a considerably smaller direct component of the current 
could have been detected. 
. This paper will be published in full in the December issue of the Physical 
eview. 
By invitation, Mr. R. Grucurist presented a paper on A new determina- 
tion of the atomic weight of osmium,! which was discussed by Messrs. HEyu, 
Pawtinc, Burcess, and HUMPHREYS. 
1 From a dissertation entitled ‘‘The Preparation of Pure Osmium and the Atomic 
Weight of Osmium’”’ submitted to The Johns Hopkins University, June, 1922, in partial 
fulfillment of the requirements for the degree of Doctor of Philosophy. 
