concerning Volte? s Contact Force. 465 



exponentially connected with their chemical activity, e. g. their 

 heat of oxidation. 



It is needless to point out that in the above equation most 

 voltaic cells are included, at least if one is content to omit 

 from consideration the inert non-migrational non-chemical 

 junction of the two metals. 



Some remarkable cells of this kind have been suggested 

 where the liquids overpower the metals, so to speak ; none 

 more so than a cell specified by Hittorf *, who says that by 

 surrounding copper with a solution of a cyanide it can 

 be made electropositive to zinc, so that copper shall go into 

 solution and zinc shall be turned out, being deposited upon a 

 zinc plate. 



The scheme for this cell of Hittorf s is said to be 



Zn | ZnS0 4 | K a S0 4 | KCN | Cu. 



The object of the K 2 S0 4 is, as in many of these cells, to 

 interpose a neutral harmless substance between two solutions 

 which otherwise would precipitate each other. 



Perhaps some one will set up a cell of this kind and 

 verify the statement ; though Hittorf s is very high authority. 



Electron or Corpuscular View of Voltaic Action, 



The theory which seeks to reduce the whole material 

 universe to electric charges, their motions and interactions, 

 constitutes a gigantic subject upon which it is scarcely rash 

 to predict that a great deal will be said during the ensuing 

 century. 



Dr. Larmor (Phil. Trans*) seeks not only to explain physical 

 phenomena in general by means of electrons, but also to 

 explain the electron itself as an intrinsic aether strain. 

 Prof. J. J. Thomson (Phil. Mag. passim, especially December 

 1899) adduces experimental facts in favour of the real and 

 even isolated existence of such charged corpuscles, whether 

 they be pure electrons or not. 



Meanwhile the mode of expression in term of corpuscles is 

 less ambitious than that in terms of electrons, though both 

 are revolutionary and striking enough. Let us take it then 

 as granted hypothetically that every material atom is built 

 up of the same fundamental corpuscles, each with the usual 

 ionic charge ; a hydrogen atom being composed of about 500 

 of such corpuscles of opposite signs, a sodium atom of about 

 10,000, and a mercury atom of about 100,000 of them. 



Let every electric current (except a displacement current in 

 * Zetis. f. physical. Chem. 1892, vol. x. p. 592. 

 Phil Mag. S. 5. Vol. 49. No. 300. May 1900. 2 K 



