250 THE PHENOMENA OF MOTION 



Or the increase of mass to the diminution by 

 waste: 



In the adult man = 100 : 100 

 In the infant ... = 100: 10 

 In the old man... = 100 : 250 



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 de- 

 crease in weight, if he carry 15 Ibs. to the distance 

 of 72,000 feet with a velocity of 2^ 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 expenditure of force in mechanical effects to ten 

 times its proper amount, there will thus be estab- 

 lished only an equilibrium between waste and sup- 

 ply. 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 the next 24 hours. If this be 

 not done, the mass of the body decreases, and the 

 state characteristic of old age more or less decidedly 

 supervenes. 



With every hour of sleep the sum of available 



