snatched the sack, tore it open, and shook it out.

A number of pieces of rock fell to the floor, a couple of geologist's
hammers, a pair of socks, and a couple of small, oilcloth-covered
notebooks.

On these Fred pounced, and opened them. They were full of penciled
notes.

"They're his!" the boy exclaimed wildly. "They're Horace's notebooks!
I knew his turkey. Horace was here. Don't you see? _He_ was the sick
man!"

For a minute his companions, hardly comprehending, looked on in
amazement. Then Macgregor took one of the books from his hand. On the
inside of the cover was plainly written, "Horace Osborne, Toronto."

"It's true!" he muttered. "It must really have been Horace." Then,
collecting his wits, he added, "But he must be all right, since he's
gone away."

"No!" Fred cried. "He'd never have gone away leaving his notes and
specimens. It was his whole summer's work. He'd have thrown away
anything else. He must be dead."

"He was vaccinated. He's sure not to have died of smallpox," Peter
urged.

Fred had collapsed on the mud floor, holding the "turkey," and fairly
crying.

"He had the diamonds on him. That half-breed may have murdered him,
and then fled in a hurry. Things look like it," said Maurice aside to
Peter.

"Yes, but then Horace's body would be here," the Scotchman returned.
"I don't understand it."

"They can't have both died, either, or they'd both be here. So they
must both have gone. But no trapper would have left these valuable
pelts, any more than Horace would have left his notes."

"There's something mysterious here," said Fred, getting up resolutely,
and wiping the tears from his eyes. "Horace has been here.
Something's happened to him, and we've got to find out what it is."

"And we'll find out--if it takes all winter!" Macgregor assured him.

They searched the hut afresh, but found no clues. They now regretted
having burned the heap of rubbish, which perhaps had contained
something to throw light on the problem.

During the rest of that afternoon they searched and searched again
throughout the cabin, and prowled about its neighborhood. They dug
into the snowdrifts, poked into the brushwood, scouted into the forest
in the faint hope of finding something that would cast light on
Horace's fate. All they found was the trapper's birch canoe, laid up
ashore, and buried in snow.

At dusk they got supper, and ate it in a rather gloomy silence.

"We've nothing