S>W^ Mr Faraday's Repli/ to Dr John Davys Remarks. 



I have said that Sir Humphry Davy spoke in general terms. 

 " The mode of action by which tlie effects take place is stated 

 very generally, so generally, indeed, that probably a dozen pre- 

 cise schemes of electro-chemical action might be drawn up, dif- 

 fering essentially from each other, yet all agreeing with the 

 statement there given (482)." In this and other parts of what I 

 have written (483 — 484), which Dr Davy quotes, he thinks 

 that I have been deficient in doing justice, or in stating Sir 

 Humphry Davy's *< hypotheses" correctly. 



. Dr Davy for my word " general,'' substitutes " vagueness." 

 I used general in contradistinction to particular^ and I fear that 

 vagueness cannot, with propriety, stand in the same relation. 

 I am sure that if Sir Humphry Davy were alive, he would ap- 

 prove of the word I have used ; for what is the case ? Nearly 

 thirty years ago he put forth a general view of electro-chemical 

 action, which, as a general view, has stood the test to this day ; 

 and I have had the high pleasure of seeing the Royal Society 

 approve and print, in its Transactions of last year, a laborious 

 paper of mine, in support and confirmation of that view (I834,i 

 part ii. page 448). But that it is not a particular account is 

 shown, not merely by the manner in which Sir Humphry Davy 

 wrote, but by the sense of his expression, for, as Dr Davy says, 

 " he attached to them no undue importance, believing that our 

 philosophical systems are very imperfect, and confident that they. 

 must change more or less with the advancement of knowledge.' 

 and what have I done but helped with many others to advance 

 what he began ; to support what he founded ? 



That I am not the only one, as Dr Davy seems to think, 

 who cannot make out the precise (or, I would rather say, the 

 particular) meaning of Sir Humphry Davy in some parts of his 

 papers, may be shewn by a reference to Dr Turner's excellent 

 Elements of Chemistry, where, at page 167, of the fifth edition, 

 the author says : " The views of Davy, both in his original es- 

 say, and in his subsequent explanation (Philosophical Transac- 

 tions, 1826), were so generally and obscurely expressed that 

 chemists have never fully agreed, as to some points of the doc- 

 trine, about his real meaning. If he meant that a particle of 

 free oxygen or iroQ chlorine is in a negatively excited state, then 

 Phil. Trans. 1826, p. 390, Edin. New Phil. Journ., Oct. 1836, p. 33. 



