Open AccessExperiments on the temperature coefficient of a Kew collimator magnet
Author(s) -
G. A. Shakespear
Publication year - 1913
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1913.0079
Subject(s) - physics , magnet , collimator , electric field , earth's magnetic field , field (mathematics) , relation (database) , magnetometer , magnetic field , optics , mathematics , computer science , quantum mechanics , database , pure mathematics
It is usually assumed that the relation between the momentm t of a collimator magnet used in determining the horizontal component of the earth’s magnetic field is dependent on the temperature, the relation being given by the equationm t =m o (1 — qt—q't2 ). The evidence, however, upon which this assumption is based not appearing conclusive, the writer was led to make an independent investigation of the subject, and the present paper is an account of the experiments carried out with that object on a Kew collimating magnet of the ordinary type about 20 years old. One of the difficulties in any magnetometer observations arises from the variability of the earth’s field. Variations may be either those of a widespread nature, such as are generally dealt with under the name of diurnal variation, or those of purely local origin, due to the proximity of electric trams, dynamo-electric machinery, electric mains, or like causes Among these disturbances we may include those arising from earth currents, since these currents, to whatever cause they may be due, are often of much more considerable magnitude that is usually suspected.