

UNVEILING OF JOULE'S STATUE. 563 



was only when the body was quiescent or walking 

 about on a level or going downhill that the 

 chemical attraction between the food and the 

 oxygen dissolved in the blood developed its whole 

 energy in animal heat. He showed, further, that 

 a horse or a man employed in doing mechanical 

 work against resistance was more economical of 

 fuel than was any steam engine hitherto realised. 

 This was a very far-reaching idea, and seemed to 

 hold out prospects of greatly advancing the 

 efficiency of the steam engine. That promise has 

 not been lost. It is due to Joule more than to 

 any other individual that the great improvement 

 of surface condensation was now universal ; 

 although it was very rarely practised before 

 1860 or 1862. Between 1855 and 1862, Joule and 

 I had a small steam engine fitted up in the stable 

 of his father's house, Oakfield, for use in our joint 

 investigations on the thermic effects on fluids in 

 motion. To that little steam engine Joule ap- 

 plied a surface condenser on an entirely new 

 principle and plan, which gave us such good 

 results that starting from it he undertook a special 



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