n't that beat everything you ever heard of, Bob?" declared
Frank, turning to his chum.

"It certainly does," replied Bob, and then the ranchman's boy continued:

"Perhaps you remember me telling you some things about this queer old
uncle of dad's, Bob, and how, after he had made a name for himself, he
suddenly vanished in a night, leaving word behind that he was going to
study the biggest subject any man could ever tackle. And as he didn't
want to be bothered, he said he would leave no address behind. They've
looked for him all over Europe, Asia and Africa, but he was never heard
from again. And now to think that he's sent word to dad; and in a sealed
bottle too!"

"That looks as if he must be somewhere on the Colorado River, don't it?"
suggested Bob.

"Undoubtedly," replied the stockman; "in fact, in this brief
communication he admits that he is located somewhere along the Grand
Canyon, in a place where travelers have as yet never penetrated. I can
only guess that Uncle Felix must have been seized with a desire to
unearth treasures that might tell the history of those strange old cliff
dwellers, who occupied much of that country as long as eight hundred
years ago. All he mentions about his hiding place is to call it Echo
Cave. You never heard of such a place, did you, Mr. Hinchman; and you've
lived on the lower river many years?"

"I never did, Colonel," replied the man from Mohave City; "and perhaps
few people have climbed through that wonderful gash in the surface of
the Arizona desert as many times as I have."

"In this brief note," continued Colonel Haywood, "Uncle Felix simply
says that he has become aware of the passage of time; and since his
labors are not yet completed, and he does not wish to allow his friends
to believe him dead, he has concluded to communicate with me, his
nephew. And as he knew of no other way of doing so, he resorted to the
artifice of the floating bottle."

"Mighty considerate of him, that's sure," chuckled Frank. "Been gone now
two or three years, and suddenly remembers that there are people who
might worry about his dropping out of sight."

"But son," remarked the stockman, "don't forget that Uncle Felix is
wrapped up in his profession, and cares very little about the ties of
this world. I know him well enough for that. But it happens, singularly
enough, that just now it is of the greatest importance he should be
found, and communicated with. I would undertake the task myself,