170 



THE HUMAN MOTOR 



The economy, therefore, increases with the speed, and what 

 takes place when the work is motive is also true in the case of 

 exactly similiar resistant work. The expenditure of oxygen per 

 kilogrammetre being : 



cu. cm. cu. cm. cu. cm. 



With increasing weight 141 1-21 147 



With increasing speed 1-68 1-32 1-12 



By comparing motor and resistant work, it is found that the 

 latter benefits more than the former, from the effects of the speed. 

 Inversely if the movement is gradually reduced, a point can be 

 found at which the expenditure is almost the same, whether 

 ascending or descending a staircase, for example. Thus a man 

 weighing 70 kilogrammes gave the following results ( l ) : 



The expenditure for motor and resistant work respectively is 

 about the same for a speed of about 100 metres an hour. 



There is, therefore, no doubt that speed is an extremely im- 

 portant factor of economy. The labourer who works the fastest 

 will expend the least. Increase of load has the opposite effect. 



116. Analysis of Chauveau's Formula. Reducing his formula 

 to three terms : 



D rf = D, + Ph + V, 



which is sufficient for a first approximation, Chauveau analysed 

 it by experiment.( 2 ) By means of an ingenious contrivance, he 



( 1 ) A. Chauveau (Comptes Rendus Sciences, vol. cxxii., 1896). 



( 2 ) A. Chauveau (Comptes Rendus Sciences, 1904, vol. cxxxviii. June- 

 July). 



