DIRECTOR   Tegid Roijackers


A horse can in general draw no more up a steep hill than three men can carry; that is, from 450 to 750 pounds ; but a strong horse can draw 2000 pounds up a steep hill, which is but short. The worst way of applying the force of a horse, is to make him carry or draw up hill; for if the hill be steep, three men will do more than a horse, each man clunbing up faster with a burden of 100 pounds weight, than a horse that is loaded with 300 pounds : a difference which is owing to the position of the parts of the human body being better adapted to climb than those of a horse. On the other hand, the best way of applying the force of a horse, is an horizontal direction, wherein a man can exert least force ; thus a man, weighing 140 pounds, and drawing a boat along, by means of a rope coming over his shoulders, cannot draw above 27 pounds, or exert above one-seventh part of the force of a horse employed to the same purpose. The very best and most effectual posture in a man is that of rowing; wherein he not only acts with more muscles at once for overcoming the resistance than in any other position. but as he pulls backwards, the weight of his body assists by way of lever.—Desaguliers. The diameter of a walk for a horse-mill ought to be at least 25 or 30 feet.—Desaguliers. Some horses have carried 660 or 700 pounds, seven or eight miles, without resting, as their ordinary work; and a horse at Stourbridge carried eleven hundred weight of iron, or 1232 pounds, for eight miles.—Desaguliers, Experimental Philosophy, vol. i. Work of mules. Force C0"1'- D»y*« ' tiuance. work. Ca/anel says, that a mule works in the West Indies two hours out of about 18, witb a force of about 150 pounds, walliing three feet in a second.—Dr. Young's Philiaophy 4,5 2* 40' 1,2 These examples exhibit the great advantages which may be gained by directing the exertion of animals in a proper course, their effects being plainly reducible to the operations of mechanical powers. To describe the various modes of applying animal strength, as a first mover of mechanical engines, would greatly exceed our limits; we shall therefore merely state, that the most common machine for receiving the force of animals is the horse-walk, which affords the means of applying the action of that animal to create rotative motion. The noree-walk is formed of an horizontal lever or arm, attached to an upright spindle. The lever should not be less than twelve feet, as the labour of the animal is greatly i n creased by a small curve, which causes an unequal resistance upon his two shoulders. The machine should be so regulated that the horse may not be required to deviate from his usual pace of two miles and a half, with a burthen, an hour. The gives, in which the horse works, should not be immovably fixed to the arms, but hung by a swivel joint, so that he may place himself in the most comfortable position. The work should be supplied to the machinery as regularly as possible.