( 4()() ) 



Instccad of water uciduUited witli snlpliurio-jicid a saturated solution 

 of copper-sulpliatc was used as electrolyte: the electrodes were 

 formed in future hy two e(pu\lly larjre l>utcli hrouze coins. The hack 

 part of these coins and the battery-wires, to which they were sol- 

 dered, were vai'nished, as far as they were immersed in the electro- 

 lyte, in onler to he sure, that, during the electrolysis, the facing- 

 sides only soi-ved as pole-plates. The gauze tube was left away and 

 a screen of platinum (4X4:C.m.), hung up isolated, placed just 

 amidst the electrodes, who were 4 cm. from each other. If a copper- 

 deposit might appear on the ])latiuum, this could be ascribed to 

 electrolytic actions only. Very soon after the circuit was closed 

 (intensity rb 0,3 amp; voltage of the battery = 4 volts) there came on 

 the piece of platinum facing the anode a sharply bounded copper- 

 deposit, which, by continuation of the experiment, changed of thick- 

 ness exclusively and not of size. The experiment was continued for 

 2 days; still the I'csults remained the same. 



Now I resolved to remove the platinum screen between the electrodes, 

 to do the experiment ovei- again and repeat this several times. The 

 deposits obtained in all these cases w^ere not exactly of the same 

 size. The smallest deposit (diam. 18 mM) was obtained by hanging 

 the screen Ix'iwceu the electrodes (diam. 19 mM.), from which we 

 can conclude to a small gradual contraction to the middle. 



If two electrodes of different shape were used, then, by removing 

 the platinum screen from the anode to the kathode, the copper- 

 deposit passed from the shaj)e of one electrode into that of the other. 

 This was very clearly visible h\ using a nut as anode and a square 

 piece of sheet-copper as kathode. The hexagonal copperdeposit gra- 

 dually took a S(piaro shape. 



Superticially one would be inclined to suppose, that the only 

 thing, that has ha|»pened is the locally making of sections of the 

 envelope of the two electrodes by means of the screen, but consider- 

 ing, that, if electricity passes from one electrode to the other, the 

 stream-lines divide through the whole fluid — the current-density is 

 only larger within the above-mentioned envelope — it will be ob- 

 vious, that there must have been another cause, which made 

 some stream-lines prefer to take the way round the screen to the 

 shorter one through it. CoJisiderhig, that the resistance of the platinum 

 can be neglected in regard to that of the longer way through the fluid, 

 the explanation of the deviation of these stream-lines can oidy be 

 found in the polarisation, caused l)y the screen of platinum. 



To pro\<' the supi)(>sai, that stream-lines are going out from the elec- 

 trodes in all directious, the following experiment may serve: The 



