All that day Jo followed, and managed, when it was needed, that the herd should keep the great circle, of which the wagon cut a small chord. At sundown he came to Verde Crossing, and there was Charley with a fresh horse and food, and Jo went on in the same calm, dogged way. All the evening he followed, and far into the night, for the wild herd was now getting somewhat used to the presence of the harmless strangers, and were more easily followed; moreover, they were tiring out with perpetual traveling. They were no longer in the good grass country, they were not grain-fed like the horses on their track, and above all, the slight but continuous nervous tension was surely telling. It spoiled their appetites, but made them very thirsty. They were allowed, and as far as possible encouraged, to drink deeply at every chance. The effect of large quantities of water on a running animal is well known; it tends to stiffen the limbs and spoil the wind. Jo carefully guarded his own horse against such excess, and both he and his horse were fresh when they camped that night on the trail of the jaded mustangs. At dawn he found them easily close at hand, and though they ran at first they did not go far before they dropped into a walk. The battle seemed nearly won now, for the chief difficulty in the 'walk-down' is to keep track of the herd the first two or three days when they are fresh. All that morning Jo kept in sight, generally in close sight, of the band. About ten o'clock, Charley relieved him near Jos. Peak and that day the mustangs walked only a quarter of a mile ahead with much less spirit than the day before and circled now more north again. At night Charley was supplied with a fresh horse and followed as before. Next day the mustangs walked with heads held low, and in spite of the efforts of the Black Pacer at times they were less than a hundred yards ahead of their pursuer. The fourth and fifth days passed the same way, and now the herd was nearly back to Antelope Springs. So far all had come out as expected. The chase had been in a great circle with the wagon following a lesser circle. The wild herd was back to its starting-point, worn out; and the hunters were back, fresh and on fresh horses. The herd was kept from drinking till late in the afternoon and then driven to the Springs to swell themselves with a perfect water gorge. Now was the chance for the skilful ropers on the grain-fed horses to close in, for the sudden heavy drink was ruination, almost paralysis, of wind and limb, and it would be easy to rope and hobble them one by one.