CONTRIBUTIONS FROM THE RESEARCH LABORATORY OF 



PHYSICAL CHEMISTRY OF THE MASSACHUSETTS 



INSTITUTE OF TECHNOLOGY. — No. 59. 



THE ELECTROMOTIVE FORCE PRODUCED IN SOLUTIONS 

 BY CENTRIFUGAL ACTION. 



By Richard C. Tolman. 

 Presented by Professor A. A. Noyes. Received June 17, 1910. 



Contents. 



1. Work of previous Investigators and Purpose of this Research . . . 109 



2. Derivation of an Expression for the Electromotive Force .... 113 



The Effect of Hydration 114 



3. Kinetic Derivation of the Electromotive Force Expression .... 115 



4. Description of Apparatus 117 



The Steam Turbine 117 



The Thrust Bearing 119 



The "Spinning Top" 120 



The Rotator 122 



The Solution Tube 122 



The Electrical Connections 124 



The Mercury Contacts 125 



The Magneto 126 



The Electrical Measuring Instruments 126 



5. The Method of Procedure 126 



6. The Experimental Results 128 



7. Ratio of the Electromotive Force to the Square of the Number of 



Revolutions per Second 131 



8. The Partial Volumes of Iodine and the Iodides 131 



9. Calculation of the Transference Number 140 



The Accuracy of the Results 141 



The Effect of Pressure on the Results 141 



The Effect of the Dissolved Iodine on the Results 143 



10. Comparison of the Results with other Transference Measurements 143 



11. Summary 144 



1. "Work of Previous Investigators and Purpose of this 

 Research. 



If the passage of an electric current is associated with the actual 



transfer of matter along the conductor, a number of phenomena, de- 



