INDUSTRIAL LABOUR 395 



At the end of the seventeenth century some illustrious physi- 

 cists and geometricians, such as Sauveur, Phillippe de la Hire, 

 and Amontons, gave some consideration to the human mechanism. 

 De la Hire showed, by experiment, that the weight of a man is a 

 factor in his physical strength, and may be of actual utility, as 

 in the case of lifting weights by means of a rope and pulley up to 

 a limit of about 65 kg. He also noted that in pulling a rope up- 

 wards a man could exert more force standing than sitting. He 

 considered that 75 kg. was the maximum load which could pro- 

 fitably be carried on the shoulders of a man walking slowly on 

 level ground. He concluded that any given height can be most 

 economically reached by mounting to it by an inclined plane, 

 and he also was of opinion that human labour is not profitably 

 employed in traction, f 1 ) 



Amontons ( 2 ) concerned himself chiefly with measurements of 

 the power developed in executing rapid operations in very short 

 times. His results will be dealt with later. It should be noted 

 that most of these early researches were confined to the evaluation 

 of static force, although the above-quoted scientists were aware 

 that the work done in overcoming resistance and producing dis- 

 placement corresponded to the lifting of a weight to a certain 

 height. The prominence given to the study of hydraulic energy 

 during the seventeenth century led to a consideration of the 

 mechanical work produced by muscular activity. It was during 

 this period that Bernoulli, Bouguer, Deparcieux, Euler, and 

 Schultze carried out the investigations which have been referred 

 to in para. 119. In 1785 the great French philosopher, Cou- 

 lomb (1736-1806) ( 3 ) communicated to the " Institute " his re- 

 markable researches on " the strength of man/' although they 

 were not published in the Proceedings of the Institute until the 

 beginning of the year 1799. He proposed to investigate the 

 maximum work which could be done without injury to health in 

 the most arduous occupations. His results are dealt with later. 



Lazare Carnot ( 4 ) at the same date expressed the same views 

 as Coulomb, although he made no independent experiments. It 

 may be said that up to the year 1850 all the researches in this 

 subject were dominated exclusively by the physical point of 

 view, in spite of the birth of the science of energetics. Never- 

 theless, the work of these earlier scientists, based as it was on the 

 " degree of fatigue," was not without utility. They measured, 



(!) De La Hire (Hist. A cad, Roy. d$s Sciences, 1666 to 1686, p. 70; 

 Memoir es Acad'. Roy. des Sciences, 1699, p. 155 and 1702, p. 95). 



( 2 ) Amontons (M&moives Acad. Roy. Sciences, 1699, p. 112, and 1703, 

 p. 100). 



( 3 ) Coulomb (see his Theorie des Machines, Bachelier, 1821). 

 (*) L. Carnot, Essai sur les Machines en General, 1786. 



