But there was a difficulty in rescuing them, just as there had been in rescuing the burros. Casey could not find their tracks, and so could not follow them. He and William hunted the canyon from top to bottom and ranged far out on the valley floor without discovering anything that could be called the track of a man. Which was strange, too, in a country where footprints are held for a long, long while by the soil,--as souvenirs of man's passing, perhaps. So it transpired that Casey at length returned to the new tent just below the spring in the nameless canyon beyond Crazy Woman Lake. Chipmunks had invaded the place and feasted upon an opened package of sweet crackers, but otherwise the tent had been left inviolate. Neither Fred nor his partner had returned. Wherefore Casey opened more cans and "made himself to home," as he naively put it. He was impatient to continue his journey, but since he had nothing of his own except William, he meant to beg or buy a few things from this camp, if either of the owners showed up. Meantime he could be comfortable, since it is tacitly understood in the open land that a wayfarer may claim hospitality of any man, with or without that man's knowledge. He is expected to keep the camp clean, to leave firewood and to take nothing away with him except what is absolutely necessary to insure his getting safely to the next stopping place. Casey knew well the law, and he busied himself in setting the camp in order while he waited. But when five days and nights had slipped into history and he and William were still in sole possession, Casey began to take another viewpoint. Fred might possibly have left in a flying machine. The partner might have decamped permanently before Fred lost his nerve. Several things might have happened which would leave this particular camp and contents without a claimant. Casey studied the matter for awhile and then pulled the four suitcases from beneath the cots and proceeded to investigate. The first one that he opened had a note folded and addressed to Fred. Casey read it through without the slightest compunction. The handwriting was different from that of the first note, hurried and scrawly, the words connected with faint lines. Here is what Fred's partner had written: