HORSE-CHESTNUT 



2842 



HORSE POWER 



may be watered when warm if due care is 

 taken; the best practice is to let him have a 

 swallow of water, then pull his head out of 

 the trough, let him have another swallow and 

 pull his head out again. Continue this prac- 

 tice until the most of his thirst has been 

 quenched. The danger in watering a horse 

 when he is hot comes not from the water, but 

 because a large quantity of water striking his 

 stomach at one time chills it or partially 

 paralyzes it, resulting in acute trouble. A 

 horse should have a chance to drink every 

 five hours, or more often if convenient. 



It will cost $75 to $125 per year to maintain 

 a horse doing medium work. This will include 

 feed and shoeing. The efficiency of a horse 

 will of course depend on the length of his 

 working day. Every owner of work horses 

 should so plan his work that his teams do not 

 stand idle at any season of the year. 



DISEASES OF HORSES. Under their various head- 

 ings in these volumes the following diseases of 

 horses are treated: 

 Distemper Heaves 



Glanders Spavin 



Consult Johnstone's The Horse Book; Harper's 

 Management and Breeding of Horses; Hayes' 

 Illustrated Horse Breaking; Lydekker's The 

 Horse and Its Relatives. 



HORSE-CHESTNUT, a species of ornamen- 

 tal trees and shrubs, with showy white, yellow 

 or red flowers and large, opposite, fan-shaped 

 leaves. Many of these trees grow to heights 

 of sixty to eighty feet, and are hardy, with 

 the exception of the Californian and Hima- 

 layan species. They thrive best in moist, loamy 

 soil. The sleds are large, brown and highly 

 polished, and the bitter meats were at one time 

 used as food for animals, particularly horses, 

 from which fact the name was derived. The 

 horse-chestnut is in no way allied to the sweet 

 chestnut, except in name; it is more orna- 

 mental than useful. The several species found 

 in North America are smaller than the true 

 horse-chestnut, and their wood is of less value. 

 See CHESTNUT. 



HORSE FLY, also called GADFLY, an active, 

 strong-flying black fly which, because it is a 

 great water drinker, is generally found near 

 inland ponds and streams in all parts of the 

 United States and Canada during the summer. 

 These flies, which attack both men and ani- 

 mals, particularly horses and cattle, are a great 

 pest along country roads and in pine woods, 

 although their bite is not as painful as that 

 of a mosquito, as no poison is injected. The 

 young (pupae) appear first in early spring, 



and the full-grown fly, which appears from 

 May to July, has a broad head, large eyes and 

 two thin wings. There are 1,500 species, prob- 

 ably 200 of which live in America, and the 

 largest, found in the Southern states, is an 

 inch and a quarter long. The terrible disease 

 known as malignant pustule is carried to men 

 by horse flies from diseased cattle which they 

 bite. 



HORSE LATITUDES, the name given by 

 mariners to a belt in the Atlantic Ocean, near 

 the tropic of Cancer, notorious for its tedious 

 calms. It is said that in colonial times vessels 

 freighted with horses from New England to 

 the West Indies were often so long detained 

 under the scorching rays of the sun in this 

 belt of calms that many of the animals per- 

 ished because of lack of water, and because of 

 this the name was applied. The term, how- 

 ever, is given generally to the same belt in 

 other oceans. See DOLDRUMS. 



HORSE POWER is the unit in which the 

 power of an engine is measured. It was de- 

 termined by James Watt, after many experi- 

 ments to find the loads that strong draft 

 horses could pull, to be the power required 

 to lift a weight of 33,000 pounds one foot in 

 one minute. If an engine moves the same 

 load one foot in one-half or one-quarter the 

 time, it is twice or four times as powerful, and 

 has therefore two or four horse power. That is, 

 the power is proportional to the time used to 

 pull the load. 



If a man weighing 175 pounds climbs seven 

 flights of stairs to a height of seventy-five feet, 

 he will do 13,125 foot-pounds of work. If he 



does it in one minute, he will exert ' 125 



33,000 



or .39 horse power. If the climb requires five 

 minutes, the power will be one-fifth as much, 

 or .078 horse power. 



How the Horse Power of an Engine is De- 

 termined. Since the development of the gaso- 

 line engine considerable confusion has arisen 

 because of various means of determining power, 

 and it is not uncommon to see an automobile 

 advertised as 20 horse power according to one 

 method of rating and 40 horse power accord- 

 ing to another. Three methods are explained 

 here. 



"Indicated" Horse Power. Steam engines 

 have long been ranked in power according to 

 the work done upon their pistons by the steam. 

 If the force exerted upon the piston of a cylin- 

 der is multiplied by the length of its stroke 

 in feet and by the number of strokes per 



