THE WORK OF 8ADI CARNOT. 5 



loss of heat in a completed cycle and in thus ignor- 

 ing the permanent transformation of a definite 

 proportion into mechanical energy ; but his propo- 

 sition that efficiency increases with increase of 

 temperature-range is still correct ; as is his asser- 

 tion of its independence of the nature of the 

 working substance. 



Oarnot's "Reflexions sur la Puissance Motrice 

 du Feu" published in 1824, escaped notice at the 

 time, was only now and then slightly referred to 

 later, until Clapeyron seized upon its salient ideas 

 and illustrated them by the use of the Watt dia- 

 gram of energy, and might, perhaps, have still re- 

 mained unknown to the world except for the fact 

 that Sir William Thomson, that greatest of modern 

 mathematical physicists, fortunately, when still a 

 youth and at the commencement of his own great 

 work, discovered it, revealed its extraordinary 

 merit, and, readjusting Carnot's principles in ac- 

 cordance with the modern views of heat-energy, 

 gave it the place that it is so well entitled to in 

 the list of the era-making books of the age. But 

 it still remained inaccessible to all who could not 

 find the original paper until, only a few years 

 since, it was reprinted by Gauthier-Villars, the 

 great publishing house of Paris, accompanied by a 

 biographical sketch by the younger brother, which 



