Charley called up Willie and told him they were about to leave the forest and would be in Oakdale in about four hours. Then the wireless was quickly dismantled and packed, and the little party started across the burned area once more, on their way out to the distant road. They did not forget to examine the ground as they went. They had gone perhaps a hundred feet when Charley noticed a heap of burned leaves. They were in the cut-over area, and the floor of the forest had apparently been carpeted thinly and evenly with leaves. So the little mound caught his eye. At first he thought nothing of it. But when his glance swept the surrounding ground and he saw how very thin the ashy coating was, and what a dense pile of ashes was in this little heap, he wondered why the leaves should have collected in this way. Without as yet really suspecting anything, he walked over to the heap and began to rake the ashes from one side of it with a little stick. Many of the burned leaves still retained perfectly their shape and outline. The serrated edges and the feathery veining were distinct in 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."