194 



THE HUMAN MOTOR 



ture. By reducing the latter, the yield is improved (115 and 

 following), and what is even more important, the yield improves 

 in proportion to the work done. 



Example : 54,993 kilogrammetres of work done on the bicycle 

 dynamometer, f 1 ) 



And, with varying speed (fig. 138) : 



so that increase of speed increases the yield up to a certain limit 

 and thereafter decreases it. 



J* n*t>rs 70 80 



_Fw. 138, 



Variations of the Yield. 



90 



Speed can exercise the same influence on the yield of inanimate 

 motors. The following results were obtained with an internal 

 combustion engine ( 2 ) : 



(*) Jules Amar, Le Rendement, pp. 61-3. 



() Hopkinson and Ricardo (G6nie Civil, 4th May, 1907). 



