last horse died down the canyon, the implication of
mystery lying heavy behind the words.

Casey went back to the tent and read the note through again twice,
studying each word as if he hoped to twist some added information out of
it. It sounded as though the writer had expected his partner back from
some trip and had left the note for him, since he had not considered it
necessary to explain what it was that he had seen again in a different
place. Casey wondered if it might not have been that strange light which
he himself had followed. Whatever it was, the fellow had not liked it. His
going had all the earmarks of flight.

Well, then, why had the last horse died down the canyon? Casey decided
that he would go and see, though he was not hankering for exercise that
day. He took a long drink of water, somewhat shamefacedly filled a new
canteen that lay on a pile of odds and ends near the tent door, and
started down the canyon. It couldn't be far, but he might want a drink
before he got back, and Casey had had enough of thirst.

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.