THE WORK OF SADI CARNOT. 9 



takes the amount of power required to exert an 

 energy equal to that needed to raise one cubic 

 meter of water through a height of one meter, 

 as his unit; this is 1000 kilogrammeters, taken 

 as his unit of motive power; while he says that 

 this is the equivalent of 2.7 of his units of 

 heat; which latter quantity would be destroyed 

 in its production of this amount of power, or 

 rather work. His unit of heat is thus seen 

 to be 1 000 -f- 2. 7, or 370 kilogram meters. This 

 is almost identical with the figure obtained by 

 Mayer, more than ten years later, and from 

 presumably the same approximate physical data, 

 the best then available, in the absence of a Reg- 

 nault to determine the exact values. Mayer ob- 

 tained 365, a number which the later work of 

 Regnault enabled us to prove to be 15 per cent, 

 too low, a conclusion verified experimentally by 

 the labors of Joule and his successors. Carnot was 

 thus a discoverer of the equivalence of the units of 

 heat and work, as well as the revealer of the prin- 

 ciples which have come to be known by his name. 

 Had he lived a little longer, there can be little 

 doubt that he would have established the facts, as 

 well as the principles, by convincing proof. His 

 early death frustrated his designs, and deprived the 



