Intelligence and Miscellaneous Articles. 479 



Zn SOJH 2 SOJK 2 S0 4 jK 2 Pt. 



Such an explanation appears to me to be much more simple than 

 one which involves the idea that neutral zinc, when placed in a 

 neutral solution, shoots off positive ions, leaving the remaining 

 portion of the metal negative ; the electric charges which convert 

 the atoms into ions consisting of a something, and the charging 

 being accomplished in a manner, of which, as Prof. Ostwald 

 admits (p. 148), no explanation can be given. 



Other experiments are quoted which seem no less inconclusive 

 than the above in favour of the dissociation theory* The slow 

 dissolution of copper in weak oxygenated sulphuric acid would 

 seem to be explained at least as well on the view that the copper 

 is first oxidized, and that the oxide of copper then dissolves (copper 

 oxide, but not metallic copper, being capable of doing so with 

 evolution of heat), as on the view that the hydrogen ions of 

 the acid are oxidized, and thus give place for the copper ions shot 

 off from the metal. The dissolution of gold in chlorine-water 

 obviously requires no recourse to the free ion theory for an expla- 

 nation ; nor does the following experiment, which practically closes 

 the list of Prof. Ostwald's " proofs." A beaker containing ferrous- 

 chloride solution is connected, by means of a siphon containing 

 sodium-chloride solution, with another beaker containing chlorine 

 solution : on inserting connected platinum plates into the beakers a 

 current passes, and the ferrous chloride becomes chlorinated to ferric 

 chloride. Here the platinum in the one beaker is slightly acted on 

 by the chlorine, and therefore becomes electropositive towards the 

 platinum in the beaker with the ferrous chloride ; the latter pla- 

 tinum consequently becomes electronegative, the iron atoms in its 

 proximity become more than usually electropositive, being thereby 

 rendered capable of attaching to themselves more chlorine, accord- 

 ing to the following scheme : — 



Fe^ 1 Cl:PeCl CliFeCl ClJNa Olfefa OlrCl 



L/l : i : i ; . + 



Pt j i | Pt. 



Fe^J Cl:FeCl CljFeCl CljNa ClJNa CljCl 



It is perhaps more probable that the chlorine atoms which the 

 sodium atoms on the extreme right combine with are derived, not 

 directly from the chlorine molecules as represented in this scheme, 

 but from molecules of hydrochloric acid or platinum chloride 

 present in the liquid. The chlorination of the ferrous chloride 

 naturally occurs with those molecules which are nearest to the 

 negative platiuum, as Prof. Ostwald observes is the case. It is 

 di Hi cult to see why such an experiment should be regarded as a 

 proof of the dissociation theory. 



All these experiments seem to be on a par with one described 

 some time ago by Prof. Ostw r ald, consisting in the production of a 



