aECEN'T PROGRESS IN THEORETICAL PHYSICS. 205 



RECENT PROGRESS IN THEORETICAL PHYSICS. 



BY JOHN" E. DAVIES, A. M., M. D., 

 Professor of Physics in the University of Wisconsin. 



The present paper is the first of a series intended to give, in a 

 collected and condensed form, the results of recent theoretical ad- 

 vances in the Physical Sciences. The researches by which these 

 advances have been made are partly experimental and partly math- 

 ematical. Some of them are most lucidly presented by Prof P. Gr. 

 Tait in his "Recent Advances in Physical Science," while those which 

 I shall present are only briefly mentioned by him, or else are omit- 

 ted altogether. Prof. Tait, however, alludes to those which he 

 does mention, in such terms as to imply that he regards them, 

 nevertheless, as of the greatest importance, and to be omitted 

 chiefly on account of want of time. 



A complete review of these researches would include Clausius' 

 remarkable theorems upon the mechanics of a great number of 

 molecules, and Boltzmann's results in the same direction, together 

 with their application to the theorj' of heat; the studies of Helmholtz 

 and Thompson upon the vortex motion of fluids and their analogues 

 among magnetic forces and electric currents; Thompson's ex- 

 planation of the magnetic rotation of the plane of polarization 

 of circularly polarized light, first experimentallj'' shown by Fara- 

 day; the experimental researches of Jamin, Rowland, Stoletow, 

 Bouty, and others, in magnetism; Rankine's hypothesis of molecu- 

 lar vortices; Clerk Maxwell's wonderful electro-magnetic theory 

 of light, with the experimental researches thereon by Boltzmann 

 and others; the explanation of anomalous dispersion by Ketteler 

 of Bonn; the mathematical relations of vibratory and translatory 

 motions in fluids, by Challis; the explanation of the blue color 

 and polarization of the sky by Lord Rayleigh; as also his remarka- 

 ble results upon Resonance and Sound generallj'; the mathe- 



