Terrestrial Electric Observatory
Published: 2017-10-27
Total Pages: 36
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Excerpt from Bulletin of the Terrestrial Electric Observatory of Fernando Sanford, Palo Alto, California, Vol. 2: Summary of Observations on Earth Potential, Air Potential Gradients, and Earth-Currents; September 1923-December 1924 In Volume I of the bulletin of this observatory were published the results of a long series of measurements of what was believed to be a diurnal variation of the electric potential of the earth at this station, and a discussion in which the proposed explanation of this variation was found in an electrostatic induction by a negatively electrified sun and a negatively electrified moon upon the earth. The method by which this diurnal varia tion was detected was described, but owing to lack of space the possible causes of variation in a quadrant electrometer used as was the one in the investigation were not fully discussed. Since that time there have been a number of suggestions of other possible ways than the one suggested of accounting for the observed results, so that it seems proper to begin this report with a discussion of these possibilities. The arrangement of the electrometer and its connections was shown in Figure 2 of Volume I, and for the purpose of this discussion this figure is reproduced here as Figure 1. In this figure, E represents a quadrant electrometer of which a and b are the quadrant pairs. The electrometer stands on a wooden pier, which is not shown in the figure. One quadrant pair, marked a, is connected by a copper wire to the metal case of the instrument, and through it to the wire cage surrounding the whole apparatus and to the water system of Palo Alto. The other pair of quad rants, b, is connected by an enameled copper wire to an insulated con ductor, C, which consists of a coil of copper wire which is immersed in a dilute copper sulphate solution in a Dewar flask. The flask is contained in a metal case, and this case is placed in a heavy porcelain jar, from which it is insulated by paraffin blocks. The jar has a porcelain cover through which the Wire from 17 passes, and the wire is insulated from both the jar and the Dewar flask by paraffin plugs. For most of the distance between the electrometer and C the connecting wire passes through glass tubes, but these tubes are open at both ends. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
