464 report — 1884. 



On the Seat of the Electromotive Forces in the Voltaic Cell. 

 By Professor Oliver J. Lodge, D.Sc. 



(A communication ordered by the General Committee to be printed in txtenso 



among the Reports.) 



As this is the first formal discussion ever held in Section A, I may be- 

 permitted in starting to say with what hope I look forward to these dis- 

 cussions in the future, and how auxions I am that they should succeed. 

 I have attended the meetings of the British Association consecutively for 

 twelve years, and have been gradually more and more impressed with the 

 small result the Sectional meetings have, as compared with what might be 

 expected considering the magnitude of the men who frequently take part 

 in them. In this Section room physicists from all parts of the British 

 Isles, as well as from Europe and America, are more frequently to be met 

 with than at the meetings of the Royal Society itself, and the whole 

 atmosphere ought to be favourable to a free and informal interchange of 

 opinions, most beneficial, instructive, and stimulating to the younger men 

 like myself. And to a great extent this is the case, especially when our 

 present sectional President is at the meeting, whether in the chair or out 

 of it. But still as a rule, mitigated it is true by a few brilliant exceptions, 

 there is a long list of somewhat dreary papers to be worked through every 

 day, the discussion on each being nipped in the bud in order to get on to- 

 the next and clear off the list. 



In favour of this practice of encouraging papers rather than discussion, 

 it may be truly urged that useful discussion on abstract papers such as we 

 are likely to have in this Section is almost impossible : only in case he 

 has been recently working at a similar subject, does an ordinary physicist 

 feel competent even to ask a pertinent question. But if papers on fun- 

 damental or controversial topics were encouraged and definitely asked for 

 in good time beforehand, workers might be encouraged to look up that 

 particular subject specially, to read its literature, to make experiments 

 on it perhaps, and generally to give it that careful thought without which 

 discussions can neither be lively nor fruitful. Abstract papers can at any 

 time be communicated to one of the learned societies whose business is 

 with papers and their publication, and where the general public are not 

 admitted. It was with these ideas that the Secretaries of the Section 

 last year agitated lor the inauguration of such discussions, and, thanks to 

 the energy of Dr. MacAlister, the first of them now begins at this unique 

 and most interesting meeting. 



The subject chosen for the present discussion illustrates in a remark- 

 able way the need for such conversations. It is scarcely credible at the 

 present rate of progress that, eighty-four years after the discovery of the 

 voltaic pile, opinion should still be utterly divided as to the seat of the main 

 E.M.F. in it. I venture to hope that it may now be decided, and a sub- 

 stantial agreement arrived at with respect to it. My business is to open the 

 discussion, but it so happens that for some seven or eight years I have 

 believed myself to see more or less clearly to the root of this particular 

 matter, and a laborious review of the literature of the subject has only 

 Btrengthened my conviction. Having therefore strong and definite views- 

 I can hardly help letting them appear, and without assuming prematurely 



