UNVEILING OF JO ULE'S S TA TUE. 56 5 



Very early, however, in his working time Joule 

 brought out the mechanical equivalent of heat, 

 and in a paper at the British Association at Cork 

 in 1843, published afterwards in the Philosophical 

 Magazine, he gave the number " 770." Six years 

 later a second determination gave him a result 

 about \ per cent, larger, and twenty-nine years 

 later he completed a third determination. The 

 result of this final investigation of Joule's is 772*43 

 Manchester foot Ibs. for the quantity of heat re- 

 quired to warm from 60 to 61 Fahr., one pound 

 of water weighed in vacuum : which is about -$ per 

 cent, greater than the result of 1849 expressed in 

 the same term. 



In the year 1824 a great theory was originated 

 by a very young man, who died only a few years 

 later Sadi Carnot, son of the Republican War 

 Minister and uncle of the present President of the 

 French Republic. It was he who made " Carnot's 

 theory " a household word throughout the world 

 of science ; and great as is the French President, 

 much as he has done and is doing for his country 

 and the world, in after times his uncle Sadi will be 



