World Magnetic Data

Abstract

WITH reference to the article "The Earth‘s Surface Magnetic Field and its Secular Change" by Prof. S. Chapman in Nature of January 31, Commander Elliott B. Roberts, chief of the Division of Geomagnetism and Seismology, U.S. Coast and Geodetic Survey, Department of Commerce, Washington 25, writes : "The Department of Terrestrial Magnetism of the Carnegie Institution of Washington adopted a change of policy after the accomplishment of the monumental magnetic study culminating in the iso-magnetic chart series for 1945.0 and publication 578. Routine work in magnetic surveying and compilation of isomagnetic charts will no longer be performed by the Department, which will henceforth restrict itself to experimental and theoretical scientific researches. The Coast and Geodetic Survey has assumed the function, in addition to its normal work of magnetic field surveys in the United States, of collecting all available magnetic field and observatory data from world-wide sources. It is intended to maintain a national reference library of such data for future American use in connexion with the compilation of world isomagnetic charts. The Bureau will continue to compile United States charts on its own account, and, by arrangement with the Hydrographic Office, United States Navy, will henceforth compile world isomagnetic charts, in editions successive to the 1945.0 series. The Bureau solicits magnetic data and copies of isomagnetic charts from all world-wide sources and will undertake in exchange to furnish any required data of American origin."