178 



THE HUMAN MOTOR 



maximum daily work is that which takes place in the most econo- 

 mical manner. 



Lau1ani6, however, found that this was not the case.( x ) 

 Certain experiments with a man on the authoi's friction dyna- 

 mometer (see Technics, 221) gave the following consumptions of 

 oxygen : 



The mechanical maximum of 905 kilogrammetres does not 

 coincide with the economical maximum of 2-16 cu. cms. per kilo- 

 grammetre. It will be seen in the same way that the minimum 

 expenditure in walking, without carrying a load, is at a speed of 

 about 4-500 km. per hour.( 2 ) Our muscles, as a result of long 

 habit and acquired or hereditary experience, function so as to 

 economise the store of energy, and adapt their effort and their 

 speed with an inimitable precision and certainty to this end, 

 by the regulating action of the nervous system. 



122. The Maximum Work of Man. (1) From the Mechanical 

 Point of View. From the industrial point of view, the mechanical 

 work estimated in kilogrammetres must be considered in most 

 trades. As Montgolfier said, " It is live force that pays." This 

 work is evaluated by determining the power of the subject, the 

 product of his effort, and his speed in unit time, a second, and by 

 multiplying this power (F X v) by the effective duration of the 

 labour in seconds, whence : 



T == F X v X t. 



Particular values of these three factors can be found, so that 

 the product F X v X t is a maximum. T will then represent 

 man's greatest daily output. 



(!) Laulante (Traiti de Physiologic, 2nd edn., Paris, 1905, p. 803). 

 ( 2 ) Jules Amar (Journal de Physiologic, 1911, p. 217). See A. Imbert, 

 Mode de Fonctionnement Economique de I'Organisme, 1902 (Coll. Scienta). 



