The twenty thousand pounds so engrossed his thoughts that he did not attend to any slight soreness of foot, or stiffness of limb.

But had he been really as fresh and as alert, as when he first set off, he would be able to go the second twenty miles with as much ease as the first, and so on, the third, &c.

Which leads to a palpable absurdity.

When a horse of spirit is nearly half tired, by the stimulus of the spur, added to the proper management of the bit, he may be put so much upon his mettle, that he would appear to a standerby, as fresh and as high spirited as if he had not gone a mile.

Nay, probably, the horse himself, while in the heat and passion occasioned by this stimulus, would not feel any fatigue; but it would be strangely contrary to all reason and experience, to argue from such an appearance that, if the stimulus were continued, the horse would never be tired.