236 MOTIVE POWER EMPLOYED

resistance of the carriages in winter would begreater than that shewn in the Table, we mayperhaps take the power of a horse as equal to112lbs., the mean of Tables III. and IV. , tra-velling at the rate of two miles an hour, ortwenty miles a day, which, on a level Rail-road, would make the weight of goods con-veyed equal to ten tons.

Taking then ten tons, moved over the spaceof twenty miles a day, as the performance of ahorse, the effect will be equal to 200 tons onemile; and, as this performance is effected atthat pace or velocity which the horse inad-vertently falls into himself, we may consider ithis maximum effect . I have not in the Tablesgiven the speed at which the horses travelled ;that would vary much, according to the resist-ance presented in the different parts of (lieroad ; but the average velocity of Table III.did not amount to more than two miles an

hour. And I am inclined to think, from ntten

tively noticing the speed of the horses in theother* at various parts of the road, that thevelocity w ith which they travelled would not (be more.

I am not acquainted with any experimentsmade on the performance of horses, travellingat different rates of speed.—The rapid diminu-tion of their power, from the great portion of