98 



PROCEEDINGS OP THE AMERICAN ACADEMY. 



TABLE VI. Zinc versus Amalgam. 



a saturated amalgam may be considered the potential of the pure metal. 

 In the case of zinc this is true within a few thousandths of a volt ; in the 

 case of cadmium the difference between the solid metal and the saturated 

 amalgam is 0.45 volt at 30°, and .054 volt at 0°. 



Summary. 



The main points of the present paper may be summarized as fol- 

 lows : — 



(1) A convenient method of measuring electromotive force directly to 

 any desired number of decimal places is described. 



(2) Cadmium amalgams as far as concentrations of three per cent and 

 zinc amalgams to concentrations of at least one per cent obey closely the 

 laws of dilute solution. 



(3) The use of the Helmholtz equation for the temperature coefficient 

 of a cell offers in these cases an accurate method of determining thermal 

 quantities. 



