Magnetic Surveys 1

Abstract

THE first volume referred, to below may be regarded as the coping-stone of the work done for the Coast and Geodetic Survey by Dr. Bauer during his tenure of the office of chief of division of terrestrial magnetism. Dr. Bauer had actually transferred his services to the Carnegie Institution of Washington before the volume appeared, but the responsibility for the work seems entirely his. The volume represents a complete magnetic survey of the United States for the epoch January 1, 1905, based on observations at 4149 stations, including 3311 in the United States itself, 575 in Canada, 201 in Mexico, and 62 in the West Indies. The great majority of the stations were occupied by Coast and Geodetic observers, but acknowledgments are made to Señor Felipe Valle for results from some seventy of the Mexican stations, and to Dr. King and Prof. Stupart for a good many results from Canada. In the United States the density of the stations varied from one per ninety square miles in Maryland to one per 2924 square miles in Idaho, the average being one per 973 square miles. Details as to instruments, methods, and sites of stations are not given, having been dealt with in previous volumes of the Survey.