through the glass, then as carefully looked at Charley's thumb. Then he
chuckled. "We've taken another king in this little checker game," he said.
"Look at that."

While Mr. Morton held the lantern for them, the two boys studied the
burned ball of clay. On it were a number of distinct thumb-prints, now
turned into solid brick by the action of the fire. The boys looked at each
other questioningly and then at Mr. Morton.

"It's a clever rogue who doesn't trip himself up somewhere," chuckled the
ranger. "What happened is as clear as daylight. Collins and his companion
found this clay while they were inspecting your camp. They must have
suspected that it was fire-clay and that you had found a deposit of value.
They took some along to test, and rolled what was left into a ball again,
thinking you would never notice the difference. But they forgot that clay
would take finger-prints so readily, and they have left their calling
cards behind them."

The ranger carefully wrapped the clay ball in his handkerchief, and then
in a newspaper. "Let me have this," he said. "The police may have some
duplicate prints somewhere. We don't know what Collins and his pal are up
to, but we have something here that we may find very useful. It isn't
every crook that is so considerate as to leave his thumb-prints behind
him."




Chapter XVI