238 THE PHENOMENA OF MOTION 



brium during sleep = 100 = 17 waking hours, = 7 

 hours of sleep, we obtain the following proportions. 

 The mechanical effects are to those in the shape of 

 formation of new parts : 



In the adult man = 100 : 100 



In the infant . . = 25 : 250 (24 : 286) 



In the old man . = 125 : 50 (118 : 43) 



Or the increase of mass to the diminution of waste : 



In the adult man == 100 : 100 



In the infant . . = 100 : 10 (9) 



In the old man . = 100 : 250 (274) 



It is consequently clear, that if the old man performs 

 an amount of work proportional to the sleeping hours 

 of the adult, the waste will be greater than the supply ; 

 that is, his body will rapidly decrease in weight, if he 

 carry 15 Ibs. to the distance of 72,000 feet with a ve- 

 locity of 2j feet in the second ; but he will be able, 

 without injury, to carry 6 Ibs. to the same distance. 



In the infant the increase is to the decrease as 10 to 

 1, and consequently, if we in his case increase the ex- 

 penditure of force in mechanical effects to ten times its 

 proper amount, there will thus be established only an 

 equilibrium between waste and supply. The child, 

 indeed, will not grow ; but neither will it lose weight. 



If, in the adult man, the consumption of force for 

 mechanical purposes in 24 hours be augmented beyond 

 the amount restorable in seven hours of sleep, then, if 

 the equilibrium is to be restored, less force, in the same 

 proportion, must be expended in mechanical effects in 



