PAPERS OX CHEMISTRY AND PHYSICS 339 



lu conclusion, the author wishes to recognize the help 

 received from the early work of Professor C. T. Knipp 

 on this problem, and to express his thanks to him for his 

 advice and aid thronghont the research, and to Professor 

 A. P. Carman for the facilities of the department. 

 Laboratory of Physics 



University of Illinois 

 May, 1922 



