BRITISH ASSOCIATION, 1843. 6j 



was such as to obscure their individual importance, and 

 merge them all in the one discovery of the mechanical 

 equivalent of heat, which, although it was the crowning 

 discovery, and of the greatest general importance, besides 

 being the most easily intelligible, was standing by itself, only 

 one step towards the end which had been reached. 



For the exaltation of the " mechanical equivalent of 

 heat " over his other discoveries, Joule was himself in 

 some degree responsible. Although the accounts of his 

 earlier discoveries were scattered about in various 

 publications, and some of them not then fully published, 

 yet in writing the account of the first determination of 

 the mechanical equivalent of heat, not only does he make 

 no attempt to bring them together, but he does not even 

 refer to their general significance. 



This research had been conducted in the six months 

 between January and August, 1843. On August 15th 

 Joule starts, in company with Mr. Eaton Hodgkinson, for 

 Cork, where the British Association was to assemble on 

 August 17th. His paper " On the Calorific Effects of 

 Magneto-Electricity and the Mechanical Value of Heat " 

 was read before the Chemical Section, August 21st, and 

 was received in general silence. The paper is dated 

 July 23rd, 1843, an d was published in full in the Philo- 

 sophical Magazine. 



In the paper itself, according to his wont, Joule con- 

 fines himself to very few remarks upon his work, but it, 

 nevertheless, contains inherent evidence, that, at the time 

 of writing, the philosophical significance of his discoveries 

 was rendered obscure to him by the dazzling effect of 

 the, to some extent meretricious, practical conclusions 

 which he conceives " may be drawn from the convertibility 



