He was not long in finding the horse that had died, and in fact all the horses that had died.  There had been four, and the manner of their death was not in the least mysterious.  They had been staked out to graze in a luxurious patch of loco weed, which is reason enough why any horse should die.

Of course, no man save an unmitigated tenderfoot would picket a horse on loco, which looks very much like wild peavine and is known the West over as the deadliest weed that grows.  A little of it mixed with a diet of grass will drive horses and cattle insane, and there is no authentic case of recovery, that I ever heard, once the infection is complete.  A lot of it will kill,—­and these poor beasts had actually been staked out to graze upon it, I suppose because it looked nice and green, and the horses liked it.

The performance matched very well the enamel-trimmed oil stove and the tinned dainties and the expensive suitcases.  Casey went back to camp feeling as though he had stumbled upon a picnic of feeble-minded persons.  He wondered what in hell two men of such a type could be doing out there, a hundred miles and more from an ice-cream soda and a barber’s chair.  He wondered too how “Fred” had expected to get himself across that hundred miles and more of dry desert country.  He must certainly be afoot, and the camp itself showed no sign of an emergency outfit having been assembled from its furnishings.

Casey made sure of that, inspecting first the bedding and food and then the cooking utensils.  Everything was complete—­lavishly so—­for two men who loved comfort.  Even their sweaters were there; and Casey knew they must have discovered that the nights can be cool even though the days are hot, in that altitude.  And there were two canteens of the size usually carried by hikers.

Casey was so worried that he could not properly enjoy his supper of pate de foi gras and crackers, with pork and beans, plum pudding—­eaten as cake—­and spiced figs and coffee.  That night he turned over on his spring-cot bed as often as if he had been lying on nettles, and when he did sleep he dreamed horribly.

Next morning he set out with William and an emergency camp outfit to trace if he could the missing men.  The great outdoors of Nevada is not kind to such as these, and Casey had too lately suffered to think with easy-going optimism that they would manage somehow.  They would die if they were left to shift for themselves, and Casey could not pretend that he did not know it.

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.