PUBLISHERS' NOTE. ix 



William Thomson, his "Account of Carnot's 

 Theory," in which that great physicist first points 

 out to the world the treasure so long concealed, 

 unnoticed, among the scientific literature, already 

 mainly antiquated, of the first quarter of the nine- 

 teenth century. The distinguished writer of this 

 paper has kindly interested himself in the scheme 

 of the Editor, and has consented to its insertion 

 as a natural and desirable commentary upon the 

 older work, and especially as exhibiting the rela- 

 tions of the fundamental principles discovered and 

 enunciated by Carnot to the modern view of the 

 nature of thermodynamic phenomena relations 

 evidently understood by that writer, but not by 

 the leaders of scientific thought of his time, and 

 therefore ignored by him in the construction of 

 his new science. 



The Appendix contains a number of Carnot's 

 own notes, too long to be inserted in the body of 

 the paper in its present form, and which have 

 therefore been removed to their present location 

 simply as a matter of convenience in book- 

 making. 



The dedication of the work to the grand- 

 nephew of the author, who by a singular coinci- 

 dence happens to-day to occupy the highest posi- 

 tion that any citizen can aspire to reach in that 



