JAMES PRESCOTT JOULE. 349 



ilia: It was read before the Chemical Section of the British Asso- 

 ciation Meeting at Cork, on the 21st of August, 1843. Some of 

 the members of the Royal Society expressed the opinion that it was 

 nonsense from beginning to end, that the author must live in some 

 benighted region, that the imponderables could not be expressed in 

 foot pounds, etc., and as a body they refused to publish it in their 

 Transactions. Sir William Thomson in 1847, though not entirely 

 persuaded of the truth of Joule's conclusions, seems to have been the 

 only one to show any degree of friendliness to them, and he advised 

 moderation in the condemnation ; nevertheless, the paper was not pub- 

 lished by the Society until 1850, seven years after its presentation.* 



Sir H. E. Roscoe said, when referring to the reception of this 

 epoch-making paper of 1843, that "the men who so bitterly opposed 

 it ought to have known better." But it is certain that they had been 

 taught differently, and when one has achieved distinction in physical 

 science he is likely to possess his own philosophy of things, in which 

 not a small part of the data is symbolic, and is represented in mind only 

 by a name, and if this name chances to suggest something mysterious, 

 as, for instance, an imponderable, the less is one likely to attempt or 

 suffer others to attempt to displace it by definite mechanical conceptions. 

 To change one's fundamental conceptions necessitates a change in his 

 philosophy, — a change that is not only difficult, but highly distasteful, 

 to everybody ; hence one could hardly expect much of a welcome to a 

 man whose work demanded such a change ; and this was the case with 

 Joule, as it was with Galileo, with Newton, with Laplace, Young, and 

 Faraday. 



His inquiries thus far had led him to the examination of the quan- 

 titative relations not only existing between heat and so-called me- 

 chanical motion, but also those existing between chemical affinities, 

 electricity, and magnetism, — in fact, between all the forms of energy in 

 inorganic phenomena; and for these he was able to show a mechanical 

 equivalent, in such a way as to make it certain that the only differ- 

 ence between the so-called forces of those days was a difference in 

 the character of the motions the bodies that exhibited the forces had. 

 In this body, all the molecules are moving in one direction at a cer- 

 tain rate, and we call it mechanical motion. In another body, the 

 molecules are individually vibrating while the body as a whole does 



* In 1849 he presented a paper to the British Association upon tlie same sub- 

 ject, which was printed, except the followinji proposition, wliich tlie committee 

 was unwillins to publish. " Friction consists in the conversion of mechanical 

 power into heat." ( ! ) 



