Prof. Tait on the Claims of Mayer and Joule. 265 



tions of this evening's discourse ? All that I have laid before 

 you is the work of a man of whom you have scarcely ever heard. 

 All that I have brought before you has been taken from the 

 labours of a German physician named Mayer/ 3 Now, in that 

 lecture, there is little about the general principle of Conserva- 

 tion of Energy, and we certainly never intended to hint that 

 Prof. Tyndall could have meant to put forward Mayer as having 

 any claims to this great generalization, although his pupil in 

 ( Macmillan ' seems to have so interpreted him. What he does 

 appear to claim for Mayer is, as in fact his lecture itself shows, 

 a succession of results regarding transformations of energy 

 which had been elaborated by mathematicians and naturalists 

 from Galileo to Davy. 



I am unwilling to enter upon matters of a more personal 

 character, but it is impossible to pass over the fact that, in 

 answer to an expostulation from Joule (having reference to this 

 lecture), Prof. Tyndall referred (Phil. Mag. 1862, second half-year, 

 p. 173) to statements he had made in a course of lectures which, 

 he now tells us, were completed before he acquired those views 

 of Mayer's claims to which Joule so naturally objected, and 

 that he now replies to Prof. Thomson and me, not by showing 

 that his lecture, to which we referred, was free from the ob- 

 jections which we urged against it, but by showing that these 

 objections could not be urged against a certain statement which 

 he quotes from a work, not published, but promised for publi- 

 cation. Referring to a passage quoted from his private materials 

 for this work, he makes the following remarkable statement : — 

 "If this recognition of Mr. Joule will not satisfy my critics, I 

 cannot help it. It is simply a difference of estimate between 

 them and me — a difference which may exist without the least 

 infraction of good faith on either side. There is nothing here 

 to ' startle' brave men, or to give the slightest colouring of 

 truth to insinuations regarding ' depreciation ' and ' suppres- 

 sion/ " It was not this, but something very different from 

 this, which startled Prof. Thomson and myself. We did not 

 insinuate, but we remarked, a tendency to depreciation and 

 suppression — a tendency which no reader knowing anything of 

 the history of science can fail to remark in that lecture as 

 reported in the Philosophical Magazine and in the popular 

 journals to which I have referred. 



I am happy to find that Prof. Tyndall now takes a view of 

 one important fundamental part of the labours of our illustrious 

 living countryman with which Prof. Thomson and I can cordi- 

 ally agree. At the same time it would be unjust to Joule to 

 omit the remark that this is but a very small part of what he 

 has done for the science of energy — work which includes re- 



