Department of Commerce, US Coast and Geodetic Survey Terrestrial Magnetism United States Magnetic Tables and Magnetic Charts for 1915

Abstract

THE latest American publication of similar scope referred to 1905, but declination charts for 1910 have been published. The observing stations used for the present charts exceeded in number those used for the 1905 charts by some 50 per cent. For declination 405 sea observations were used, and-results from 6120 land stations, including 1129 in Canada, Mexico, and the West Indies. The first set of tables give declination (D), inclination (I), and horizontal force (H) results obtained at successive epochs at repeat1 stations. The D and I results are given to the nearest 1′, the H results to the nearest 10 γ. The second set of tables gives the corrections for reducing observations taken at different epochs and in different geographical positions to the epoch January 1, 1915. They are followed by tables giving D, I, and H, first as observed at the several stations, then as reduced to January 1, 1915. The last set of tables gives for each whole degree of latitude and longitude the values for January 1, 1915, of D, I, H, total force (T), and north, east, and vertical (V) components. Latitudes from 19° to 51° N. are included. At 19° N. the longitudes range from 74° to 105° W., while at 47° N. they range from 64° to 128°. W. In these final tables the D and I results go. to 0.1°, the force results to 0.001 C.G.S.

Department of Commerce, U.S. Coast and Geodetic Survey. Terrestrial Magnetism. United States Magnetic Tables and Magnetic Charts for 1915.

By D. L. Hazard. Pp. 256 + maps 5 in pocket. (Washington: Government Printing Office, 1917.)