the ashy residues. They were interesting to see.
Charley continued to level the burned leaves on one side of the pile. At
the touch of his stick they lost their shape and crumbled into formless
ashes, even as fairy crystals of snow turn to water beneath a warm current
of air.

Suddenly Charley stopped dead still. Among the ashes turned over by his
stick was a long, thin sheet of ash. Charley looked at it a moment in
astonishment. Then he knew that it was pasteboard. He sank to his knees on
the blackened earth and with his fingers carefully worked in the still
warm ashes, raking off the upper layers of leaves gently, so as not to
disturb the bottom of the pile. Carefully he worked, until he had laid
bare a long strip of what had been pasteboard. At his touch this, like the
leaves, crumbled. But one end of it did not disintegrate. A tiny piece was
unconsumed. From the ashes Charley drew forth a charred bit of greenish
pasteboard. Swiftly but carefully he raked aside the burned pasteboard.
Then he gave a little cry. On the ground, in the very bottom of the heap,
was some candle grease. His startled exclamation brought Mr. Marlin and
Lew running to his side.

"What have you found?" asked the forester sharply.

"A piece of unconsumed pasteboard and some candle grease," said Charley
slowly. "They were under this mound of burned leaves."

"We need look no farther for the starting-place of this fire," said the
forester, his face very sober. "It is just as I suspected. This fire was
of incendiary origin. Whoever set it, placed a lighted candle inside a
pasteboard box, partly filled the box with leaves, heaped some leaves on
top of it, and hurried away. The candle probably burned for hours before
it burned low enough to set fire to the leaves. By that time the culprit
was far away and could prove an alibi."

Charley drew from his pocket the little microscope he used in his class in
botany in the high school. Over and over he turned the scorched scrap of
pasteboard, studying it intently.

"The fibers are arranged in a peculiar way," he said, "and there's an
almost invisible machine marking of a peculiar pattern. The color of the
pasteboard was a dark green."

The forester took the microscope and examined the charred fragment,
handing both, when he had finished, to Lew.

"This is our clue to the incendiary," he said slowly. "We must find where
pasteboard like that comes from and who had some of it. Meantime, do not
breathe