RELATION BETWEEN HORSE AND MASTER 221 



and protection from the elements and predatory foes; under 

 natural conditions such expenditure may be considerable. 



In Domestication. — The husbandman, with his system of 

 domestication, substitutes an artificial for a natural environ- 

 ment, relieving the horse of all responsibility in the matter of 

 feed, water, and protection, conserving to himself the energy 

 that would otherwise be expended for that purpose. There 

 is thus made available to the husbandman energy for work of 

 whatever character the horse is capable, and to just the extent 

 that energy has been saved. To balance the account, horses 

 working up to their full capacity must be furnished all that is 

 required for their subsislence and comfort; to underfeed or 

 overwork is to overdraw the account, and against one who has 

 not the usual privilege of protest. 



Economic efficiency of the horse in service is more essential 

 now than ever before, on account of the high cost of feedstufFs 

 and the continued improvement in the motor vehicles with which 

 the horse is in competition. 



Two men may ride or drive the same horse or team over the 

 same route with the same load and in the same time, yet there 

 will be a marked difference in the condition of their horses after 

 having accomplished the same task. This difference is due to a 

 more intelligent use of the available motive power in the one 

 case than in the other. If the various ways in which energy 

 may be expended in the performance of work were more care- 

 fully taken into account, both the period of usefulness and the 

 daily capacity of the average horse would be much increased. 



A Horse's Capacity for Work. — The unit of measurement 

 by which work is expressed is the foot pound or the foot ton, i.e., 

 the power required to lift a weight of one pound or one ton to a 

 height of one foot against the force of gravity. The energy re- 

 quired to do work equivalent to 33,000 foot pounds per minute 

 constitutes a horse-power. This estimate of a horse's power is 

 not literally correct, however, but exceeds the capacity for work 

 of the average horse by about one-third. 



Horses have been forced, experimentally, to do the equiva- 

 lent of Y800 foot tons in a day, but that is far in excess of their 

 normal capacity, as shown by the marked loss in weight which 



