Having thus determined the exact place of crossing, Tom concentrated his attention on this spot, examining the bark systematically, inch by inch.  But no vestige of a clew rewarded his microscopic scrutiny.  He was baffled and his curiosity and determination rose in proportion to the difficulties.  His big mouth was set tight, a menacing frown clouded his countenance, so that instinctively little Skinny refrained from speaking to him.

Tracing the apparent line of the animal’s crossing over the log, Tom scrutinized the prints on the other side, that is, the side nearest camp.  Here the prints were very clear by reason of the crust of mud caused by the dampness usually found near logs and fallen trees.  Marks on this showed like marks on hard butter.

Suddenly Tom’s attention was riveted by something directly under the apparent line of crossing, something which he had never seen the like of in all his woodland adventures since he had become a scout.  What he saw looked singularly out of place there.  Yet there it was printed in the hard crust of mud, and as clear as writing on a slate.  No human footprint was near it.  If a human being had made those marks that human being must have reached from the log to do it.  And the printing was almost too nice for that.

Utterly dismayed, Tom looked again for human footprints but the nearest were those of Hervey on the other side of the log, some ten or a dozen feet beyond.

“Did either of you fellows do that?” Tom asked, pointing.

“Does—­does it mean I can’t have the badge?” Skinny asked, apprehensive of Tom’s mood.

“Did either of you fellows do that?”

“N-no,” Skinny answered timidly.

“Have you brought any one else up here?”

“Honest—­I ain’t.”

“Well then,” said Tom, with a kind of grim finality, “either some one else who didn’t have any feet has been here or else that animal knows how to write.  Look there.”

Skinny obediently looked again.  There below the log and close to the tracks were printed as clear as day the letters H. T. They were about two inches in size.

“Take your choice,” said Tom with a kind of baffled conclusiveness which greatly impressed his little companion. "Either those letters were printed there by some one who didn’t have any feet, or else the animal knew how to write.  Either one or the other.  It’s got me guessing."

CHAPTER XXVII

THE GREATER MYSTERY

Since there was no solution of this singular puzzle, Tom did not let it continue to trouble him.  He was too busy with his duties incidental to the closing season to concern himself with mysteries which were not likely to reveal anything of value.  The kidnapping was a serious affair, and the curious discovery which he had made in the woods was soon relegated to the back of his mind by this, which was now the talk of the camp, and by his increasingly pressing labors.