ANIMAL MOTORS 287 



develop power at his maximum rate. It is also possible to 

 develop power at very nearly the maximum rate while 

 pumping. A large man working at a winch can exert 

 0.50 horse power for two minutes and one-eighth horse 

 power by the hour. It is stated that an ox will develop 

 only about two-thirds as much power as a horse, owing 

 to the fact that he moves at a much slower speed. 



404. The horse is the only animal used extensively at 

 present as a draft animal or for the production of power. 

 As reported in the Twelfth Census, the number of horses 

 and mules on the farms in the United States was 15.517,- 

 052 and 2,759,499, respectively, making a total of 18,- 

 276,551 animals. If it be assumed that each animal de- 

 velop two-thirds horse power, the combined horse power 

 while at work would be 12,184,366, an excess of 184,285 

 horse power over that used for all manufacturing pur- 

 poses during the same year, 1900. 



From a consideration of the skeleton and muscular 

 development, it is perceived that the horse is an animal 

 specially well adapted to dragging or overcoming hori- 

 zontal resistances rather than for carrying loads. With 

 man it is different. Although greatly inferior in weight, 

 man is able to bear a burden almost as great as that of a 

 horse, while at dragging he is able to exert only a small 

 horizontal effort, even when the body is inclined well for- 

 ward. The skeleton of man is composed of parts super- 

 imposed, forming a column well arranged to bear a 

 burden. The horse is able to draw upon a cart a 

 load many times his own weight, while he is unable to 

 carry upon his back a load greater than one-third his 

 weight. 



It is to man's interest that his best friend in the brute 

 world should be strong, live a long life, and waste none 

 of his vital forces. Much attention has been given to the 



