Prof. Ostwald on Chemical Action at a Distance. 155 



platinum plate, and the chlorine seems consequently not to 

 exert its action where it itself is located, but at any arbitrary 

 distance. Since, under the customary views, this phenomenon 

 presents a rather unusual aspect, I shall describe in a few 

 words a suitable arrangement of the experiment. 



The solutions in question are put into two small glass 

 beakers ; in one ferrous chloride, in the other a solution of 

 sodium chloride saturated with chlorine : in the place of the 

 latter a solution of bromine in common salt solution, or one 

 of potassium bichromate and hydrochloric acid may be con- 

 veniently used. In each glass is placed a platinum electrode, 

 and both these are joined by metallic connexion through a 

 galvanometer. Finally the circuit is closed by an inverted 

 siphon-tube filled with salt-solution, the ends of the tube being 

 closed by parchment-paper. The galvanometer indicates at 

 once a current which passes in the liquid from the ferrous 

 chloride to the chlorine, and at the electrode in the ferrous 

 chloride this salt changes into the ferric chloride. In order 

 to render it evident that the action takes place neither at the 

 parchment-paper nor uniformly in the entire liquid, but is 

 limited to the surface of the electrode, where the formation 

 of ferric ions from ferrous ions by the transfer of positive 

 electricity is alone made possible, the ferrous-chloride solution 

 (which is previously to be completely reduced by digestion 

 with iron powder) may be treated with a little potassium 

 sulphocyanate ; the development of the red-brown coloration 

 exclusively at the electrode becomes then readily apparent. 



In place of ferrous chloride there may of course be employed 

 any other " reducing " solution. In order to realize a case, 

 where the transfer of electricity takes place without the inter- 

 vention of metal ions, I have combined sodium bisulphite 

 with a solution of sodium chloride containing bromine, and 

 have observed entirely similar results ; even when the con- 

 nexion is made by a siphon filled with a solution of pure 

 salt, in a few moments the presence of sulphuric acid may be 

 detected by means of an acid solution of barium chloride, 

 while at the same time sodium bromide, that is bromine ions, 

 has been formed on the other side. 



The change in the ions of the sulphite, which here takes 

 place, may be explained in different ways. There exist in 

 sodium bisulphite solution the negative ions HS0 3 . The 

 change of these into the more stable negative ions of sulphuric 

 acid may be represented by the reaction 



2HS0 8 -r H 2 = H 2 S0 3 + H 2 S0 4 , 



in which the resulting acids may be considered as partially or 



