Letter to Lord Brougham. 107 



observed, as it seems to me, other mistakes in this volume, on 

 points of scientific history, which, venial as they are in one 

 who cannot be supposed to have devoted much of his valuable 

 time to these umbratile studies, are yet such as ought not to 

 pass without some notice. 



I must begin, however, my criticisms on your historical 

 chemistry, by repeating the grounds on which I deemed it 

 needful to controvert the statements of M. Arago respecting 

 the discovery of the composition of water. " The elope of 

 Watt, delivered before the French Academy by one of its 

 secretaries, and subjoined to the Annuaire for 1839, had just 

 been published. It was blemished by statements which re- 

 flect unjustly on the character of one whose memory is che- 

 rished among us as a bright example of the union of modesty 

 with science, of the purest love of truth with the highest facul- 

 ties for its discovery, and the most eminent success in its at- 

 tainment. Perceiving these statements to be founded in error, 

 I took the earliest opportunity of rectifying them, at the meet- 

 ing of the British Association which followed within two or 

 three weeks after I became acquainted with them, rejoiced 

 that I had it in my power, from the position in which, as 

 President of that body, I had then the honour to be placed, 

 to make the correction of the error as formal and public as 

 its promulgation had been ; and persuaded that M. Arago, as 

 soon as he should be full}' possessed of the facts, would con- 

 sider it a duty which he owes both to the Academy and him- 

 self, to retract the suspicions which he had expressed*." 



Those who feel that a sense of justice is a material part of 

 the character of illustrious men and illustrious bodies, are still 

 " waiting," not " till your fellow champion," as you express 

 it, " shall seal your adversary's doom," but till he makes the 

 amende honorable by withdrawing, in explicit terms, imputa- 

 tions which since the lithographing of the Cavendish MSS. 

 he must know to be unfounded. I am not content, my dear 

 Lord, that you should either for your " colleague" or yourself, 

 half retract and half retain those doubts which I perceive 

 that you have republished in one part of your volume, whilst 

 you disclaim them in another. 



" I cannot easily suppose," you say, " that M. Arago ever 

 intended, and I know that I never myself intended, to insinuate 

 in the slightest degree a suspicion of Mr. Cavendish having 

 borrowed from Mr. Watt." Certainly, as regards yourself 

 at least, no declaration can be more explicit than this. But 

 what then, give me leave to ask, is the significance of the fol- 

 lowing words in your now republished appendix to M. Arago's 

 * Report of the British Association for 1839, p, 22. 

 12 



