158 Prof. Oliver Lodge on the Seat of the 
Quite detached from any connection with the controversy, 
because at that time quite unintelligible to all but one or two 
here and there, two papers appeared in 1851 by the President 
of this Section, which were the triumph and apotheosis of the 
chemical theory of the source of the current in the voltaic 
cell*. In one of these papers (that on “ Hlectrolysis ”) it is 
irrefutably established, on the basis of the conservation of 
it, and an essential property of matter ?”—Page 44: “The great tendency 
of the attraction of the different chemical agents by the positive and nega- 
tive surfaces in the Voltaic apparatus seems to be to restore the electrical 
equilibrium... .The electrical energies of the metals with regard to each 
other or the substance dissolved in the water, seems to be the cause that 
disturbs the equilibrium, and the chemical changes the cause that tends 
to restore the equilibrium; and the phenomena most probably depend on 
their joint agency.” He then gives a very Voltaic account of the action 
of the pile—much in agreement with Sir Wm. Thomscn ; and endeavours 
to reconcile chemical and contact theorists by pointing out how essential 
a part chemical action plays in the production of a current, a most clear- 
sighted thing to do at that date. One more sentence may be quoted from 
this remarkable paper, though it is not quite so striking as the preceding. 
—Page 49: “These ideas are evidently directly in contradiction to the 
opinions advanced by Fabroni, and which in the early stage of the investi- 
gation appeared extremely probable, viz. that chemical changes are the 
primary cause of the phenomena of Galvanism. Before the experiments 
of M. Volta on the electricity. excited by mere contact of metals were 
published, I had to a certain extent adopted this opinion; but the new 
fact immediately proved that another power must necessarily be con- 
cerned, for it was not possible to refer the electricity exhibited by the 
opposition of metallic surfaces to any chemical alterations, particularly as 
the effect is more distinct in a dry atmosphere, in which even the most 
oxidizable metals do not change, than in a moist one, in which many 
metals undergo oxidation.” 
* Sir W. Thomson :—1. “ On the Mechanical Theory of Electrolysis and 
the Applications of the Principle of Mechanical Effect to the Measurement 
of Electromotive Forces in Absolute Units,” Phil. Mag. December 1858. 
Reprint of Mathematical and Physical Papers, vol. i. pp. 472 and 490. 
2. On the Dynamical Theory of Heat, part vi. Thermoelectric Cur- 
rents: ’ Proc. R. 8. Edin. Dec. 1851 ; Trans. R. S. Edin. 1854; Math. and 
Phys. Papers, vol. 1. pp. 232 and 316. 
Helmholtz also clearly applied the conservation of energy to Voltaic 
circuits in his memoir Dre Erhaltung der Kraft, read before the Physical 
Society of Berlin, 23 July, 1847. In this powerful memoir Prof. Helm- 
holtz sails placidly through a great part of physics, applying to various 
phenomena the then new principle of the conservation of energy. He 
regards all action as occurring at a distance, and shows, as is well known, 
that, on this hypothesis, central forces are the necessary and sufficient 
condition of conserved energy. This part may now be regarded as super- 
seded; but in the more special portions, among other things, he develops 
the mechanical theory of the H.M.F. of voltaic cells, of thermoelectric 
piles, and of magneto-machines ; anticipating in many respects the some- 
what later though independent work of Sir W. Thomson on these subjects. 
Prof. Helmholtz’s memoir is easily accessible through a translation, by 
J[ohn] Tyndall |, which appeared, in May 1853, in the “new series” of 
‘Scientific Memoirs,’ issued by Taylor and Francis. 
