So 



THE ANIMAL AS A MACHINE. 



the work performed in horizontal carriage of burdens 

 is nearly equivalent to raising the total weight one 

 foot in five, for which we have sin~i^--^ 11.5°. The 

 art of securing best results in the use of animals draw- 

 ing loads in vehicles of various sorts is that of so pro- 

 portioning load, line of pull, weight of vehicle, and 

 speed of travel as to permit the animal to take its 

 natural gait and best total effort under load, this 

 effort being measured at the traces. Obviously, the 

 lighter the wagon or cart it is found practicable to em- 

 ploy for the proposed load the better. Also, the larger 

 the loads transported in one vehicle the better, as a 

 rule ; and thus, in all large operations, heavy loads in 

 comparatively light carriages, and drawn by numbers 

 of animals, give most economical results. As inclines 

 decrease the useful work in rapid proportion with 

 their rise, the production of level and smooth roads is 

 an essential to economy. This is illustrated in the 

 case of railways, where enormous sums are expended 

 to insure straight, level, and smooth tracks. For men 

 the treadmill, and for animals well-constructed "horse- 

 powers," embodying the same principles of construc- 

 tion, give highest efficiency as measured by the work 

 performed per day, in foot-pounds or kilogrammetres. 

 Walking up a moderate incline carrying only the 

 weight of the body is the most easy and natural of all 

 methods of employing its power. This system is 

 capable, however, of but very limited application in 

 ordinary industrial work. It is oftenest seen in use in 

 threshing-machines and other agricultural apparatus. 



26. In Selection and Care in the employment of 

 men and animals, the engineer is compelled to regard 

 them as machines, to be selected with careful reference 



