12^ 



electrolytically deposited gave tlie result that this material only under- 

 goes ti-ansformation at temperatures below 100°, if it has been in 

 contact at 50° (100°) with a solution of cadmium sulphate. 



The probable and obvious conclusion is that by electrolysis we 

 get exclusively -/-cadmium, the modification which is stable at high 

 temperatures. If this were the case, the y-cadmium would be trans- 

 formed into ,i-cadmium at 100°, into ^(-cadmium at 60^ in contact 

 with the solution of the sulphate. 



If now the y-modification is really generated by electrolysis, 

 (analogous to what happens with solutions of tin salts) the Hulett 

 cells which have been measured until now would contain this 

 material as the negative electrode. 



If this modification happened to be transformed into the modifi- 

 cation which is stable at ordinary temperatures iind pressures (1 atm.), 

 this would manifest itself by a decrease in the E.M.F. 



On the one hand we are working in this case under extraordi- 

 narily favourable circumstances for stabilisation (change into the 

 «-modification) as the material formed elecirolytically is in a xery 

 fine state of division and surrounded by an electrolyte, while the 

 quantity which has to undergo transformation is so verj^ small 

 (20 or 30 milligrams), that the transformation, if it occurs, will be 

 finished in a short s[)ace of lime. 



On the other hand, and this is to be borne in mind in researches 

 of this kind, the [)0ssibility exists that the transfornuition which has 

 to take place spoutaneousb/, may be suspended, if the metal depo- 

 sited by electrolysis forms only one single modification, as the germs 

 , needed for transformation are then absent. 



11. That the stabilisation generally does not occur is shown by 

 our dilatometric observations as well as by many other facts i.e. by 

 the experiments of W. Jaeger,') Ehnst Cohen,') Bi.il') and Hulett,") 

 who all found the same E.M.F. (50 millivolt at 25° C.) for cells 

 which were constructed according to the scheme: 



Cd I Solution of I Cd-amalgam 



elect rolytically cadmium 12,5 |)er cent 



deposited | sulphate | by weight. 



How obstinately the transformation may be delayed might also 



i; Wied. Ann. 65, 106 (1898). 

 ~) Zeitschr. f. physik. Ghemie 34, 612 (1900). 

 3) Zeitschr. f. physik. Ghemie 41, 641 (1902). 

 1) Trans. Amer. Electrochem. Soc. 7, 333 (1905). 



