SADI CARNOT 235 



of this fact, but was prevented by his all too early death from 

 following up the matter, so that it remained completely 

 hidden. 



Sadi Carnot, who was born in Paris, was the second son of 

 Nicolas Marguerite Carnot, known as Napoleon's minister 

 and organiser of France's national defence. He studied 

 technical science and entered military service.^ 



His last studies, which remained incompleted, as well as 

 other notes by his hand,^ show, no less than his published 

 essay, that a rare mind was lost by his early death. We 

 will only remark that in his papers a numerical value for the 

 mechanical equivalent of heat (1000 metre-kilograms ^2.7 

 calories = 370 metre-kilograms per calorie) is given 

 without any further indications of its origin, together with 

 plans for a considerable part of the measurements later car- 

 ried out by Joule. ^ Along with these we find remarks - as 

 concerning the injuriousness of war to the race, religion, and 

 everyday and purified Christianity - which expose with re- 

 markable clearness evils still existing to-day.* 



^ Our portrait shows him at the age of seventeen in the uniform of a 

 student of the Ecole Polytechnique in Paris. Some years later, after 

 Napoleon's abdication, which resulted in his father's banishment, he 

 retired from the service in order to be able to devote hiinself, in the 

 greatest seclusion, entirely to his scientific studies. This mode of life 

 was only interrupted by a journey to Germany, where he visited his 

 father who was living in Magdeburg, and later, after publication of his 

 Reflexions, by a short re-entry into the army, during which he was made 

 a Colonel. He died early, only thirty-six years of age, the victim of an 

 epidemic of cholera. 



^ In the edition by his brother already referred to. 



3 Since Carnot's ideas had remained completely unknown, this does 

 not affect Robert Mayer's credit for having first made this equivalent 

 known, and generally, for having discovered the idea of it, nor Joule's 

 credit for having carried out the experiments; but it bears of course upon 

 the estimate we are to make of Carnot himself. 



* These remarks may be appreciated later, when the time comes for 

 such thinkers to be valued, even when they do not bring us only technical 

 progress; see pages 83-87 of the 1878 edition. 



