DEPARTMENT OF TERRESTRIAL MAGNETISM. 345 



Table 3. — Preliminary average annual changes for the Pacific Ocean — Continued. 



^Units of fourth decimal C. G. S. 



Molecular and cosmical magnetism. S. J. Barnett. Nature, vol. 107, pp. 8-9 (Mar. 3, 1921). 



This article, written in reply to one by S. Chapman, shows that the theory 

 proposed by him of the magnetic effects produced by rotation is essentially 

 identical with that of the author; it extends this theory to some particular 

 cases, and discusses the application of the theory to cosmical magnetism. 



The electron theorj- of magnetism. S. J. Barnstt. Science, n. s., vol. 53, pp. 465-475 

 (May 20, 1921). 



This is a general account of the electron theory of magnetism, developed by 

 W. Weber and numerous followers from the theory of Ampere proposed a 

 century ago. Weber's theory of diamagnetism, as originated in 1852 and 

 as slightly modified by Langevin in 1905, is given in some detail. Other 

 theories of diamagnetism proposed by J. J. Thomson, Voigt, Lorentz, and 



^Abstract of a paper read as a part of the symposium on "Recent Progress in Magnetism," 

 held at the joint meeting of the American Association for the Advancement of Science, Section 

 B. and the American Physical Society, Dec. 1920. 



