"SCIENTIFIC PAPERS." 167 



only with the full scope and completeness of Joule's research, 

 but what was more important, with the extent to which 

 Joule had himself anticipated those who followed him in 

 generalizing from his own results. Up to that time Joule's 

 work was mostly known at second hand, or by reference 

 to the paper containing the final determination of the 

 Mechanical Equivalent of Heat, in the Phil. Trans., 1850. 

 But few authors have referred to any of the series of Joule's 

 early discoveries by which he was led to the recognition 

 of the Conservation of Energy almost before he had 

 determined the Equivalent. These discoveries excited no 

 remark at the time they were made, and while Joule was 

 pursuing the equivalent others had taken up his previous 

 work, and these discoveries, including that of the Universal 

 Conservation of Energy, had been swallowed up in the 

 rising tide of science, from which they were only rescued 

 by the appearance of this volume. Until this volume 

 appeared it is improbable that any one of the many eminent 

 physicists then living had any knowledge of Joule's lecture 

 at the St. Ann's Church Reading Room, published in the 

 Courier in 1 847, containing the only full expression of his 

 views on the indestructibility of energy. 



The second volume of Joule's " Scientific Papers " 

 appeared in 1887. This contained his joint papers with 

 the Rev. Dr. Scoresby, Sir Lyon Playfair, and Sir William 

 Thomson. 



Joule not only collected his papers and edited these 

 volumes, adding numerous notes containing references to 

 subsequent researches on the various subjects, both his own 

 and others, but also added accounts of several of his 

 researches not previously published. The most important 

 of these, is, perhaps, his " Account of Experiments on 



