COSMIC RAYS MILLIKAN AND CAMERON 231 



we deny the validity of the most approved form of statement of the 

 second law. The effort to work out more fully the thermodynamic 

 implications of this complete cycle is now being made by Stern,^' 

 Tolman,^- and Zwicky,^^ as well as by ourselves.^* 



cistern, O. Zeits. f. Elrktrothrmie, ai, 448; 1925. 



" Tolman, Richard C. Proc. Nat. Acad., 14, 268, 348, 353, 1928. 



^ Zwicky, F. Proc. Nat. Acad. In press. 



^ Millikan, R. A., and Cameron, G. H. Phys. Rev., 32, 533-558 ; 1928. 



