78 



THE ANIMAL AS A MACHINE. 



24. The ''Mechanism of Transmission" of the 



power of the animal is the vehicle or other apparatus 

 through which the power is exerted in the moving of 

 the load. In some cases the load is directly applied, as 

 where pack-animals are employed ; in others a wagon 

 is used ; in still other cases the pull on a rope is made 

 effective in raising weights. A strong man can walk 

 an average of about 3^^ miles an hour 10 hours a day, 

 unloaded ; under 80 pounds he can walk at half this 

 speed seven or eight hours a day ; and he may hft at 

 long intervals 180 to 200 pounds. The work of hori- 

 zontal transport may be approximately computed by 

 taking it at 0.08 the product of weight carried into 

 distance moved over. Thus measured, we find from 

 the above statement that a man should do about 

 2,000,000 foot-pounds of work per day, his weight 

 being included in the amount taken as load. By the 

 use of a wagon, or its equivalent, the weights that may 

 be transported are increased, often, ten times or more. 

 Training may double the efificiency of a workman in 

 manual employments and enormously increase it in 

 cases of skill coming of long practice. The differences 

 between reputably first-class workmen may amount to 

 15 or 20 per cent. 



The pull of the average draught-animal is usually 

 not far from one fifth its weight. Gerstner gives us 

 the following ^ : 





Weight. 



Av. Pull. 



Vil. per 



Work per 



Work per 





Lbs. 



Lbs. 



Sec. Av. 



Sec. 



8-hr. Day. 



Man. . 



.. 150 



30 



2.5 



75 



2,160,000 



Horse. 



.. 600 



120 



4.0 



480 



13,824,000 



Ox,.. 



. . 600 



120 



2.5 



300 



8,640,000 



Mule. . 



.. 500 



100 



3-5 



350 



10,080,000 



Ass . . . 



.. 360 



72 



2-5 



180 



5,184,000 







* Mechanik, vol. 



i. 





