Directions for magnetic measurements

Magneticians generally will welcome the appearance of this publication, both because of its excellent presentation of the essentials of field and office practice and because of its general suggestiveness. Its aim is “to present the subject matter in such form that an observer familiar with the use of instruments of precision but without experience in magnetic work may be able to make in satisfactory manner the various observations incident to the determination of the magnetic elements, without other assistance than that to be obtained from these Directions.” Not only has the author effected this purpose but he has also covered the subject of magnetic computations as fully as that of observation, by concise derivation of the various formulae involved, the discussion of their use, and numerous tables particularly helpful to the practical computer. The manual presents in a very concise and finished form, the results of the experience of the United States Coast and Geodetic Survey since its magnetic work was placed on a systematic basis by C. A. Schott, and developed subsequently, in the separate Division of Terrestrial Magnetism of that Survey, under the direction of Dr. L. A. Bauer; the system of observation, and reduction of results, as well as the general directions to observers in the field as given, are essentially those developed by the latter on the foundation laid by Schott.