92 



PROCEEDINGS OP THE AMERICAN ACADEMY. 



different concentration ; (3) solid cadmium electrode opposed to cadmium 

 amalgam ; (4) solid zinc electrode opposed to zinc amalgam. 



Class 1. 



Table I. gives the values found for the electromotive forces of cells 

 with electrodes of cadmium amalgams of different concentration. The 

 lower extremity of each arm of the H tube was filled with amalgam to 

 a depth of two or three centimeters, so that a fairly large volume might 

 be present. Measurements were made at such temperatures that the 

 amalgams were wholly liquid, for their partial solidification is an insidious 

 cause of error capable of producing serious results, especially in this 

 case of cadmium. The three per cent amalgam begins to freeze at about 

 0°, becoming wholly solid at a slightly lower temperature (about — 3°) ; 

 while the nine per cent amalgam is not wholly liquid until 45° is reached. 

 For this reason measurements 10 in Table I. had to be made at high 

 temperatures. Normal cadmic sulphate was the electrolyte. 



TABLE T. Cadmidm Amalgams. 



