THE EARTH'S MAGNETISM.^ 



By L. A. Bauer, 



Director, Department of Terrestrial Magnetism, Carnegie Institution of 



Washington. 



[With 9 plates.] 



It is indeed a great privilege and pleasure to give a lecture at Ox- 

 ford, where Edmund Halley, whose name the founder has so wisely 

 coupled with this lectureship, labored devotedly in the interest of 

 science; and to be permitted, in some small measure, to pay the debt 

 of terrestrial magnetism, and my own personal debt as well, tc this 

 illustrious investigator. 



Halley's varied scientific activity and his wide sympathies were well 

 set forth by the Halley lecturer- of two years ago, who had as his 

 subject an astronomical one, " The stars in their courses." Last year's 

 lecture,^ " Large earthquakes," by that zealous pioneer, Prof. Milne, 

 again exemplified both the scope of this lectureship and the fact that 

 Halley's interest and achievements in geophysical science, though not 

 generally so well known as his astronomical discoveries, were no less 

 great. The subject of the lecture to-night, " The earth's magnetism," 

 is one in which Halley's name stands out preeminent among the early 

 students of the science. As it is a large subject and one in which there 

 might be much discursive rambling, we shall do well to limit ourselves 

 somewhat — to choose our starting point and then proceed in certain 

 definite directions. 



The adopted flag of the Chinese Republic consists of five stripes, 

 [)artly because, as I am told, in China all good things are five — five 

 seasons, five principal grains, five genii, five relationships that make 

 up life, and five points of the compass, north, south, east, west, and 

 center. For, to the Chinese, the starting-out point is as important as 

 the point to which, or direction in which, a journey is made. So 

 it also must be with us to-night. 



1 The fourth " Halley lecture." delivered in the schools of the University of Oxford on 

 May 22, 191.3 ; illustrated by lantern slides. Reprinted, after revision by the author and 

 with added illustrations, from Bedrock, vol. 2, No. 3, October, 1913, pp. 273-294. 



-Prof. H. H. Turner, D. Sc, D. C. L., F. R. S., Savilian professor of astronomy, Univer 

 sity of Oxford (see Bedrock, vol. 1, No. 1, April, 1912, pp. 88-107). 



3 Published in Bedrock, vol. 1, No. 2, July, 1912, pp. 137-156. 



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