SCIENCE 



FRiDAy, May 20, 1921 



The Electron Theory of Magnetism: De. S. 

 J. Baknbtt 465 



The American Assodatioii for the Advance- 

 ment of Science: — 



Spring Meeting of the Executive Commit- 

 tee: Dk. Bdkton E. Livingston 475 



Medals of the National Academy of Sciences: 

 Dr. E. E. Slosson 478 



Third Award of the Daniel Giraud Elliot 

 Medal: Dr. Henry I'aiefield Osborn.... 480 



Scientific Events: — 



The United States Patent Office; The Na- 

 tional Geographic Society; Exchange of 

 Professors of Engineering ietween Ameri- 

 can and French Universities; Grants from 

 the Bache Fund i 481 



Sdientific Notes and News 483 



University and Educational News 484 



Discussion and Correspondence: — 



Effect of Dormant Lime Sulfur upon the 

 Control of Apple Blotch: Dr. E. F. Gdba. 

 Crows and Starlings: F. E. Welsh. The 

 Synchronal Flashmg of Fireflies: Otto 

 A. Reinking. Franz Steindachner : De. H. 

 W. Wiley 484 



Scientific BooTcs: — 



Groth's Chemische Krystallographie : Pro- 

 fessor Edwaed H. Keaus 486 



Special Articles: 



The Change in the Fat of Peanut-fed Bah- 

 ms: S. T. DowELL 487 



The American Society of Mammalogists 487 



MSS. intended for publication and books, etc., intended for 

 review should be sent to The Editor of Science, Garrison-on- 

 HudBon, N. Y. 



THE ELECTRON THEORY OF 

 MAGNETISMi 



Ever since the time of Faraday it has been 

 known that all varieties of matter can be 

 grouped in three classes on the basis of mag- 

 netic behavior, ferromagnetic, paramagnetic 

 and diam-agnetic. 



It would be far too much to claim that the 

 electron theory has as yet given anything like 

 a complete account of the phenomena wit- 

 nessed in connection with these three types of 

 magnetism; but it is the only theory proposed 

 which has been in any way satisfactory and 

 which appears to hold out any hope for the 

 future. 



In accordance with the plans of this sym- 

 posium I shall restrict myself to a consider- 

 ation of the more general aspects of the theory 

 and its simplest applications. For the sake 

 of logical completeness I shall have to refer to 

 many matters well known. The extension of 

 the theory and its application to more special 

 and complex cases, in so far as they can be 

 handled on this occasion, will be treated by 

 my colleagues. 



The first electrical theory of f erromagnetism 

 was proposed by Ampere just about one hun- 

 dred years ago. On the basis of his own ex- 

 periments on the behavior of electric circuits 

 and magnets, and on the assumption, abeady 

 justified, that magnetism is a molecular and 

 not a molar phenomenon, he concluded that 

 the molecule of iron is the seat of a per- 

 manent electrical whirl and thus essentially a 

 permanent magnet with its axis perpendicular 

 to the whirl. When the iron is fully mag- 

 netized, all the whirls are oriented alike, and 



1 A paper read as a part of the symposium on re- 

 cent progress in magnetism held at the joint meet- 

 ing of the American Association for the Advance- 

 ment of Science, Section B, and the Americaji 

 Physical Society, December, 1920. Revised, Jan- 

 uary, 1921. 



