O.v A Determination of the Elements of Terrestrial 

 Magnetism at Halifax, N. S., August, 1904. By 

 Prof. Stephen M. Dixon, M. A., Dalhousie College^ 

 Halifax. 



{Read Slut November, I'MU.) 



The observations of the Magnetic Elements recorded in this 

 paper were made at Point Pleasant, Halifax, August 25 and 

 26, 1904. The magnetometer and dip circle used were obtained 

 through Professor C. H. McLeod, from McGill Univ^ersity, the 

 chronometer was lent by Mr. C. G. Shultz and the theodolite 

 by Mr. W. A. Hendry, C. E. 



As it is hoped that these observations will be followed by a 

 complete magnetic survey of the Maritime Provinces, and as 

 this is the first time the matter has been brought before the 

 Institute of Science, a brief sketch will be given of the 

 phenomena of Terrestrial Magnetism. In preparing this sketch 

 the writer has borrowed largely from the Magnetic Declination 

 Tables and Isogonic Charts by Dr. L. A. Bauer. The practical 

 importance of one of the elements, usually called by land 

 surveyors the variation of the compass, cannot be overesti- 

 mated in this province, where those who are interested in land 

 and mine surveying know the trouble that is continually arising 

 on account of the neglect of this very matter. In other coun- 

 tries terrestrial magnetism has been studied in connection with 

 geolog}^ and many interesting discoveries have been made. 

 Magnetic surveys have led to the devising of magnetic methods 

 in prospecting for iron ores. To the student in physics and to 

 the astronomex', the subject is equally interesting, on account of 

 the relation of surface changes on the sun to variations in the 

 earth's magnetism. The subject then is of general interest and 

 its importance has been emphasized by the establishment, in 

 December 'last, by the trustees of Carnegie Institution, of a 

 Department of International Research in Terrestrial Mag- 



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