178 THOMSON ON CARNOT'S 



enable us to calculate, from the data supplied by 

 Regnault, the abscissa and ordinate for each of the 

 curves described above (17) corresponding to any 

 assumed temperature t. After the explanations of 

 33, 34, 35, 36, it is only necessary to add that c 

 is a quantity of which the value is very nearly 

 unity, and would be exactly so were the capacity 

 of water for heat the same at every temperature 

 as it is between and 1; and that the value of 

 c(S t), for any assigned values of S and t, is 

 found, by subtracting the number corresponding 

 to t from the number corresponding to s, in the 

 column headed "Nombre des unites de chaleur 

 abandonnees par un kilogramme d'eau en descen- 

 dant de T a 0," of the last table (at the end of 

 the tenth memoir) of Kegnault's work. By 

 giving S the value 230, and by substituting suc- 

 cessively 220, 210, 200, etc., for t, values for x, y, 

 x', y', have been found, which are exhibited in the 

 table opposite. 



