466 Prof. 0. Lodge or the Controversy 



free space) be associated with a transfer of corpuscles, a con- 

 vection of ionic charges, whether in liquids or in metals or in 

 gases ; the only difference being lhat in liquids the travelling 

 corpuscle carries the whole atom with it, whereas in gases it 

 can travel in some cases isolated from all the rest of an atom*, 

 though in other cases it may be clogged with a considerable 

 molecular aggregate of atoms t ; while in solids presumably a 

 corpuscle can only travel by being handed on from one atom 

 to the next: though a shift inside each atom will correspond 

 to a polarisation current. 



At an electrode the corpuscle leaves its ion to do the best it 

 can, and passes on into the metal, each atom receiving it into 

 its atomic grouping and instantaneously passing on an equal 

 corpuscle to the next : or at least that is what I suppose to 

 happen, consistently with the hypothesis. At a junction of 

 two metals, then, a corpuscle which had formed part of an atom 

 of one metal finds itself received and incorporated by a different 

 kind of atom. This may clearly involve a gain or a loss of 

 energy, and accordingly some propelling or opposing E.M.F. 

 It may be expressed if we choose somewhat in the language 

 of Helmholtz's hypothesis, that one metal attracts electricity 

 more forcibly than another. If the excess energy takes the 

 form of molecular agitation, such a procedure may entirely 

 account for the Peltier and Seebeck phenomena. 



I have spoken of it above (April, p. 364) as a futile kind of 

 " transmutation " : " transmutation " because a portion of the 

 substance of say an iron atom enters into and becomes part of 

 the substance of a copper atom ; " futile " because there is no 

 effective conversion of iron into copper, since the amount of 

 each metal remains the same as before. 



If corpuscles could be passed into a metal without being 

 passed out again there would be a kind of transmutation, and 

 this is hypothetically done when a body is charged with 

 negative electricity ; it has gained corpuscles which do not 

 belong to it. But the fact that they do not belong to it — being 

 evidently there on sufferance and tending to escape as soon 

 as possible — shows that there is no real transmutation : a 

 charged sodium atom is not a mere sodium atom but a 

 sodium monad ion ; it has one negative corpuscle too many. 



It might be thought that by giving to a metal charges of 

 positive and negative electricity alternately some extra atoms 

 could be built up : but unfortunately this is not consistent with 

 the fact that, under known circumstances, the negatively 



* J. J. Thomson, Phil. Mag. Dec. 1899. 



f Cf. Chattock, Phil. Mag. Nov. 1899 5 also Rutherford, Townsend, 

 Wilson, &c , Phil. Trans. 



