work with the pup, for the forest was full of creatures that constantly
excited the young animal. The training required no end of patience: but
Charley loved the dog and never wearied in his efforts. By the time he had
completed his labors with the pup, his own shadow was hardly more constant
and quiet than the dog.

Charley was elated one day when the dog signaled the approach of a
fisherman by no more than the faintest sort of a bark, and then at
command, came promptly to heel and remained there, silent and watchful. It
was the pup's first test with human beings. The fisherman proved to be
one of two who were making their way along the margin of the run. Charley
and the dog remained quietly behind some bushes until the fishermen were
out of sight and hearing. Then Charley praised his little pup and went on.

His efforts with the dog, however, did not prevent him from thinking of
other matters. Day after day his mind returned to the problem of the
forest fire and the piece of green pasteboard. Ever since he had found the
telltale pile of ashes and the charred pasteboard beneath it, Charley had
been turning the problem over in his mind. How he was to solve the puzzle
he did not see. Somewhere, he felt sure, he had seen pasteboard like the
charred piece now in possession of Mr. Morton; but when or where he had
seen it, he had not the slightest recollection. How he was ever to find
another piece like it, he could not imagine; for as a fire patrol he had
neither time nor opportunity to mingle with people.

He could see just one possibility of success. Undoubtedly there was a
great deal more of the green pasteboard in the world than had been
contained in the burned box. Hence persons other than the incendiary must
have some of that same pasteboard. Perhaps some of those persons might
bring a bit of it into the forest. Campers and fishermen often brought