342 Note bj/ M. Ampere on Heat and Light 



me more pleasure in relation to my last published paper, the 

 Eighth Series*, than the thought that whilst I was helping to 

 elucidate a still obscure branch of science, I was able to sup- 

 port the views advanced twenty-eight years ago, and for the 

 first time, by our great philosopher. 



I have such extreme dislike to controversy that I shall not 

 prolong these remarks, and regret much that I have been 

 obliged to make them. I am not conscious of having been 

 unjust to Sir Humphry Davy, to whom 1 am anxious to give 

 all due honour ; but, on the other hand, I feel anxious lest 

 Dr. Davy should inadvertently be doing injury to his brother 

 by attaching a meaning, sometimes of particularity and some- 

 times of extension, to his words which I am sure he would 

 never himself have claimed, but Which, on the contrary, I feel 

 he has disavowed in saying " that our philosophical systems 

 are very imperfect," and in expressing his confidence "that 

 they must change more or less with the advancement of science" 

 On these points, however, neither Dr. Davy nor myself can 

 now assume to be judges, since with respect to them he has 

 made us both partisans. Dr. Davy has not made me aware 

 of anything that I need change; and I am quite willing to 

 leave the matter as it stands in the printed papers before sci- 

 entific men, with only this request, which I am sure before- 

 hand will be granted, that such parts of Sir Humphry Davy's 

 papers and my own as relate to the subject in question, be 

 considered both as to their letter and spirit before any con- 

 clusion be drawn. 



Royal Institution, January 9, 1835. 



XXXVIII. Note by M. Ampere on Heat and Light consi- 

 dered as the Results of Vibratory Motion. \ 

 T^HANKS to the labours of Young, Arago, and Fresnel, it 

 * is now demonstrated that light is produced by the vibra- 

 tions of a fluid diffused throughout space, and which has been 

 called aether. Radiant heat, which follows in its propagation 

 the same laws, may be explained in the same manner. But 

 when heat is propagated from the most highly heated part of 

 a body, to another which is less heated, the laws of its trans- 

 mission are entirely different : instead of a vibratory motion 

 propagated in undulations or waves in such a manner that 

 every wave leaves at rest the fluid which it sets in motion at 

 the instant of its passage, we have a motion propagated gra- 

 dually in such a manner that the part which originally was 

 the hottest, and consequently the most agitated (explaining 



[* Reprinted in Loud, and Edinb. Phil. Mag., vol. vi. p. 34 et scq. — Edit.] 

 t From the Annates dc Clrimic ct dc Physique, tome lviii. p. 434—444. 



