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tion. Now I ought to say something of the 

 electrical, mechanical, and chemical character of 

 Joule's work, although to examine it properly 

 would require the space not of one short address 

 but of a whole course of lectures illustrated by 

 experiment. A great surprise that came out very 

 early in Joule's work was burning without heat 

 an absolutely novel idea which Joule developed 

 most wonderfully and most magnificently by his 

 experiments on the generation of heat in the 

 voltaic battery. Joule was the first to develop the 

 idea, and it came to him not as a bright flash of 

 genius, but as the demonstrated result of years of 

 hard, measuring, calculating work. This burning 

 without heat was a fundamental idea that pervaded 

 all Joule's work. A few years later he expanded 

 it in an admirable way. About 1844, in a joint 

 paper by himself and Scoresby, " On the Mechanical 

 Powers of Electromagnetism, Steam and Horses," 

 he brought out the startling but truly philo- 

 sophical idea that when a man or any other 

 animal walked uphill only a part of the heat of 

 combustion of his food was developed, and that it 



