129 



cells of 0.047 Volt E.M.F, on another, cells of 0.050 Volt E.MF. 

 were obtained. 



As our dilatometric measurements had shown that stabilisation 

 occurs with great velocity at 50°^ we prepared cells (C and 0) at 

 47°. 9. The dilute amalgam was then taken out and an 8.5 percent 

 (by weight) amalgam was put in, while a fresh solution of cadmium 

 sulphate was used. We substituted an 8.5 per cent amalgam for a 12.5 

 percent as our intention was to measure these cells also at 0° C. ; 

 At this temperature the 12.5 percent amalgam is a monophase system 

 and such a system must not be used. 



In this way we found at 25°. C. 



Cell C: 0.04745 Volt. 

 Cell 0: 0.05022 „ 

 The cadmium in cell C had thus been stabilised at 47°. 9. 



16. In order to check the results found uji to this point we also 

 determined the E. M. F. of our stable and metastable cells at 0° C. 

 If the ditferences in E. M. F. at 25°.0 between the different cells 

 were really to be ascribed to the presence of «-cadmium (cell C) and 

 y-cadmium (cell 0) the difference which was at 25°.0 C. 2.8 millivolt 

 ought to increase at 0° C. as we are at that temperature at a greater 

 distance from the metastable transition point «-cadmium ^/-cadmium. 



The measurements at 0° C. gave the following results: 



cell C : 0.05225 Volt, 

 cell 0: 0.05626 „ 



While the difference was 2.8 millivolt at 25°.0 C. it has increased 

 as might be expected to 4.0 millivolt at 0° C. 



17. Several phenomena which are described by Hülett, but which 

 are obscure until now may find an explanation in the light of our 

 experiments. Hulett says : "A number of cells were made with addition 

 of Cd (0H)2 thinking this might make a more uniform cadmium 

 deposit; also the air was completely removed from three before 

 sealing, and in others the air was removed and the cell saturated 

 with nitrogen and with hydrogen. All of these gave very variable 

 results, but in each case only 10 milligrams of cadmium had been 

 deposited on the spiral, and 1 have lately learned this is too little 

 cadmium, since some cells prepared as above described, excepting that 

 only 10 mg. of cadmium was deposited on each spiral, showed the 

 same irregularities and tendency to constantly decreasing electromotive 

 force. These cells were recently all discharged and then reversing 



9 , 

 Proceedings Royal Acad. Amsterdam. Vol. XVII. 



