130 



the current about 26 mg. of fadmiuin was deposited on each platinum 

 spiral, and lliej seem to be all coming together nice!}- and to the 

 value indicated bv the old cells". 



18. Our observations agree perfect ly with those of Hulett but 

 we have to add the following restrictions: A number of our cells 

 in which only 10 mgrs. of cadmium were de[)Osited indicated imme- 

 diately after formatioji an E. M. F. of 0.0502 Volt at 25''.0 which 

 decreased during 2 days. Then it became constant : 0.047 Volt. 

 Transformatioji into «-cadmium had consequently occurred; the fact 

 that only a small cpiantity of cadmium is present causes the E. M. F. 

 to reach very soon its definite lowest value. The phenomenon obser- 

 ved by Hulett is tlierefore the quick stabilisation of y-cadmium. 



19.. Prof. Hulett has been kind enough to communicate to us 

 the following facts: "Twelve cells which had been sealed after 

 formation remained unchanged from March J 8''' 1905 to May 7^'' 19J4, 

 i. e. during 9 years. Their E. M, F. has been during all this time 

 0,0505 Volt. The quantity of cadmium on the spirals varies between 

 3.7 and 13.7 mgrs. of cadmium". 



20. The decrease of E. M. F. which had been observed with cells 

 which contain, only 10 mgrs. of cadmium is consequently not to be 

 ascribed to the minute quantity of metal ^) deposited on the spirals; 

 this quantity is much less in the cells which have been constant 

 during 9 years. The reason of the decrease in E. M. F. of those cells 

 is the transformation of y-cadmium into r<-cadmium. 



21. In order to check this conclusion we prepai'ed a number of 

 cells (at room temperature) which only contained 5 mgrs. of cadmium 

 on the spirals. Some of these remained metastable (0.050 Volt) w hile 

 others were transformed into the stable form (0.047 Volt) after some days. 



22. Although the discussion of a number of questions must be 

 delayed until a subsequent paper, we will mention here the beha\iour 

 of cadmium which has not been formed by electrolysis. 



In our second paper we stated that a piece of cadmium chosen 

 at random which had been produced from the molten metal contains 

 three modifications : «, /i and y-cadmium. If such is the case, it might 



i) Oberbeck found [Wied. Ann. 31, 337 US87)] that a layer of metal A of 

 'i X 10-'' mm. suffices to give to a metal on which it has been deposited the 

 potential of A. As the surface of the spirals in the H. G. was 0.28 cm ~ the layer 

 of cadmium deposited is much thicker. 



