Change* of Voltaic Energy of Alloys during Fusion. 27 



the polarization current I venture, though with considerable 

 diffidence, to ask whether it really is evidence of actual elec- 

 trolysis. It is explained by the statement that a coating of 

 liberated ions is formed on the electrode, and that these can- 

 not be discharged so as to become ordinary atoms till the 

 potential of the electrode attains a certain value, they conse- 

 quently remain there and cause a reverse current. But 

 might not such a current be caused by a similar coating of 

 simple but undecomposed molecules ; such molecules are, I 

 believe, not fully saturated compounds, but still possess a 

 certain amount of residual affinity, or, on the older electro- 

 chemical theory, a certain amount of unneutralized charge; 

 these would be attracted to the electrodes and would present 

 their + and — ends to the — and + electrodes respectively : 

 a charge would thus be retained on the electrodes after the 

 battery was disconnected, and this charge would cause a 

 reverse current when the two electrodes were connected 

 together. The action in fact would be similar to that in a 

 condenser. Such an explanation may obviate objections 

 which can, perhaps, be urged against the idea of a coating of 

 ions, for it seems difficult to see why a certain E.M.F. should 

 be reached before the atoms can discharge themselves, unless 

 we imagine a definite attraction between an atom and its 

 charge, or why the E.M.F. required to effect this discharge 

 should not always be the same whenever the same element is 

 liberated ; it also obviates the necessity of regarding an ion 

 as possessing any form of charge which a free atom does not. 

 Whatever be the value of these suggestions, and of the 

 objections raised against that part of Olausius's conception 

 which supposes the presence of a/ewfree atoms in a liquid owing 

 to the accidental superheating of some of the molecules, it 

 must be borne in mind that this view is totally distinct from 

 the modern dissociation theory, that all the molecules are dis- 

 sociated, and that too not by heat but by their affinity for 

 electrical charges of incredible origin, and possessing hitherto 

 unknown characteristics. 



IY. On Changes of Voltaic Energy of Alloys during Fusion. 

 By Dr. G. Gore, F.R.S.* 



MJ. REGNAULD has observed that liquid gallium is 

 • electropositive to solid gallium in a neutral solution 

 of gallous sulphate (Comptes Rendus Acad. Sci. June 10, 

 1878 ; ' Chemical News/ vol. xxxviii. p. 33). He states that 

 * Communicated by the Author. 



