54 McBAIN [1902 Donnan 



tended itself down into the red layer, although the meniscus 

 remained stationary; in (11) and (12) the brownish yellow 

 moved toward the anode. 



The foregoing experiments, the general behavior, the freez- 

 ing points and conductivity alone and mixed, etc., are all con- 

 sistently explained by the authors' conclusion that the simple 

 cobalt cation is red, and that the blue is a complex anion 

 C0CI3' or CoCl/'. Similarly the brownish yellow of ferric and 

 copper chlorides is attributed to a complex anion. 



1902. W. Hittorf. 



Bemerkiingen iiber die Bestimmungen der Ueberfuhrungszahlen der lonen 

 wahrend der Elektroljse ihrer Losungen. Das Verhalten der Diaphragmen bei 

 derselben. Arch. Neerl. (2) 6, 671 ; Zeit. phys. Chem., J9, 613 ; 43, 239. Drude's 

 Ann., 9, 243. 



Apparatus : N-shaped tubes and superposed glasses ; capacity 

 of anode vessel 20-40g ; no middle portion. Various dia- 

 phragms were employed, viz. : bolting silk (bolt), earthenware 

 (earth), intestinal membrane (darm) and gold beaters' skin 

 (gold). Anode Cd, the cathode is indicated below in the fourth 

 column. One experiment each. 



The author observed with a differential spectroscope the cur- 

 rents occasioned in the solutions by the diaphragms ; these oc- 

 curred only with the chlorides of cadmium, calcium, barium, 

 and strontium, the nitrates of silver and thallium, and the strong 

 free acids ; not with the nitrates, acetates, and iodides of the 

 alkalis. The action is described as the splitting up of the solu- 

 tion into a more concentrated and a more dilute, which are 

 ejected at opposite sides of the diaphragm. The diaphragms 

 which modify the transport number are : intestinal membrane, 

 gold-beaters' skin, membrane of an egg, and gelatine. With- 

 out influence are : agar agar, and earthenware. 



