The measurement of magnetic susceptibilities of low order

Abstract

The magnetic susceptibilities of various kinds of rock specimens have recently assumed considerable importance in relation to the new magnetic survey of the British Isles, and in this connection as a member of the Iron Ore Committee of the Conjoint Board of Scientific Studies, the author was asked to endeavour to obtain a solution of the problem, which, in its essentials, consisted mainly in the development of some instrument capable of measurement of susceptibilites of low order. At the suggestion of the Committee the author has prepared the present communication which contains an account of the instrument used, together with some of the results to which it has led. The particular work on rock specimens which was the origin of the enquiry is given in “A Report on Magnetic Disturbances in Northamptonshire and Leicestershire and their Relation to the Geological Structure.” The type of instrument which has been used in the work described in the present communication is a modification of that known as the Curie balance, and depends for its action upon the pull exerted by a magnet.