J 42 



of electrolytic chi'omium, which contains a great quantity of hydrogen, 

 is placed in a solution of chronions-sniphate, as described in the first 

 paper, this will at first present a sti'ongly negative potential in 

 consequence of the great hydrogen charge. When the chromium is 

 left in contact with the solution, it loses its liydrogen at the surface. 

 The j^otential shifts along the line Q'R in the direction of /il. The 

 potential rises then to Eii = — 0.27 , F, as was communicated in the 

 first paper. 



This is, therefore, probably the chromium potential that the metal 

 presents for a hydrogen ciiarge 1, because the chromium will cede 

 hydrogen to the solution till its pressure has become one atmosjdieie. 



When such an electrode is now cathodically polarized in chromous- 

 sulphate, hydrogen is generated. The chromium regains its hydrogen 

 charge, and with it its active potential. 



By the aid of figure 1 the phenomena for cathodic polarisation 

 are, therefore, to be explained in a simple way. Also the activating 

 action of the anodic polarization on electi-olytic chromium can l)e 

 accounted for by the aid of these considerations, when theditfusion 

 of the hydrogen in the metal is taken into account. 



When the chromium has been electrolytically separated, it has a 

 high hydrogen content, of which we assume llial it is the same 

 throughout the entire thickness of the layei-. When in figui-e 2 I)F 



D 



£ 



B BB 



E 

 Fig. 2. 



r 



r 



represents this thickness and we plot the concentration of the hydrogen 

 normal to it, this is represented by a horizontal straight line AG. 

 The line GF represents the sui-face of contact of the chromium with 

 the liquid. On accou)it of the great hydrogen content in the boundary 

 surface the chromium will possess a very active potential. When 



