a half to three
`` How did he know it ? '' continued Bob . `` By the looks of the tracks and the distance between them . When a horse is walking his hind foot covers about half the print made by his fore foot , and the tracks are from two and a half to three feet apart . When the horse is trotting the tracks are not so distinct , the one made by the fore foot being nearly covered up , and they are from seven to eight feet apart . When he is running the print of only one foot can be seen , as a general thing the ground about the tracks is considerably disturbed , and they are from seven to twelve feet apart . '' If Carey and the rest of the squad did not learn to their entire satisfaction that they were not out on a picnic this time , the horses on which they were mounted certainly did , for before an hour had passed they were very much in need of water -- so much so that Bob brought them down to a trot , and at last to a walk .