QUANTITY OF FOOD EEQUIllED. 67 



In calculating the diet for exertion, it has been estimated 

 that work at a walk requires from 6J grains to 9 grains of 

 nitrogenous matter for 7,233 foot-pounds of work performed ; 

 and that work at a trot or fast pace demands from 15 J grains 

 to 24 grains for every 7,233 foot-pounds of work. 



With regard to the amount of force exerted by horses 

 during labour, which it is important to know in order to 

 judge of the quantity of food required, it may be mentioned 

 that a one-horse engine working for ten hours per day raises 

 19,799,360 pounds one foot high — this being the calculated 

 amount of energy expended in ten hours if it could be all at 

 once exercised. But this is probably much more than a horse 

 could exert; a very hard day's work would in all likelihood not 

 be more than 16,400,000 foot-pounds, which would be exercised 

 by a horse pulling a load along at a walk for eight hours. 

 Eight hours' slow walking, with a traction force of 100 lbs., is 

 equal to 8,436,571 foot-pounds per diem. Slow farm work is 

 equal to 11,211,000 foot-pounds a day. "With regard to fast 

 work, the amount of foot-pounds raised is less, for the effort 

 required is sudden, and the waste of tissue or force is conse- 

 quently greater. The actual amount of work done is less, for 

 the reason that the animal cannot sustain the effort, and owing 

 to the greater waste incurred more food is needed. A Paris 

 omnibus horse is calculated to expend 4,377,433 foot-pounds 

 per diem ; in a mail-cart the amount was found to be 5,786,000. 



But it is evident that work both at a trot and walk must 

 vary considerably, depending upon the speed, and also the 

 weight carried or drawn. However, it has been suggested 

 that the following estimate is fairly correct : — 



A hard day's work for a horse at a walk ) , , p^^ nnn £ j. j 



would be j 11,500,000 foot-pounds. 



A moderate day's work, ditto 8,500,000 „ 



A hard day's work for a horse at a trot ) 7 ooo nnn 



of fast pace would bo \ ^^'^'^'""" 



A moderate day's work, ditto 3,500,000 „ 



F 2 



