400 



THE HUMAN MOTOR 



The production for eight hours of actual labour was therefore : 

 13-7 X 0-76 X 3,600 X 8 = 299,865 kilogrammetres 

 13-3 X 0-757 x 3,600 X 8 = 287,081 



i.e., a quantity of 300,000 kilogrammetres 



approximately. 



In practice, at a speed of -75 metres, the maximum period of 

 actual labour is 6 hours. Hence the real daily output is : 



300,000 X 6 = 225,000 kilogrammetres. 

 8 



The most accurate experiments show that the speed and the 

 effort should not be reduced to less than 0-50 m. and 15 kilo- 

 grammes respectively. Hachette, with a man working quite 

 easily at 3-8 kgm. per second, obtained a daily output of barely 

 110,000 kilogrammetres of work done. 



306. The muscular power, acting on the crank-handle, develops 

 a variable quantity of work. It is not only the muscles of the 



arms which furnish the necessary 



g A effort. The horizontal component of 



..... --------- the weight of the man has also a 



certain effect. As a rule, the work- 

 man adopts an attitude making 65 

 with the direction that the crank 

 handle must take, and he acts by a 

 lever having its fulcrum at the height 

 of the loins, or at about -f of his height. 

 If he weighs 65 kilogrammes, his effort 

 will be : 

 FIG. 275w fip; y Q 



= 39 kilogrammes. 

 o 



The effective component is (fig. 275) : 



OA = 39 x sin 25 C (or cos 65) = 39 x 0423 = 16-500 kg. 

 If the body is inclined 45, the component is : 



39 X 0-707 = 27-600 kg. 

 but then the equilibrium of the man is upset. 



One of the earliest observers, Sauveur, found the values of 

 12-24 kg. and 0-51 m. for a continuous labour of 8 hours. This 

 gives for the day's work : 



12-24 X 0-51 x 3,600 X 8 = 260,000 kilogrammetres 

 approximately, and this is a maximum. 1 



( J ) BSIidor (Architecture HydmuHque i. p. 72 quoted above). 



