e simplest
explanation.

The secrecy of the Indian's movements might be accounted for by a
natural reserve, and specially by a shyness before the uniform. But
where was he hiding? That he was never far away was apparent. Mahon
added to his other duties this new trail.

He realised the difficulty of his task after several distinct twinges
of that strange sense developed in the wary at being under unseen eyes.
It could not be a bohunk, for the workmen were not clever enough to
trail him unseen. Also it was not an inimical inspection. Only the
Indian could trail the trailer with such unerring confidence.

It was not unnatural, therefore, that as time went on the Indian
assumed the proportions of a gripping mystery.

On the track of the new problem, Sergeant Mahon took to roaming the
woods by night. His reward was unexpected and unsought--it had no
connection whatever with the Indian. He discovered that the bohunks
were meeting in their hundreds under cover of the darkness. To satisfy
himself that an outside menace was not added to the perils surrounding
the trestle, Mahon took to inspecting the camp from hiding whenever he
came on one of these gatherings. The fact that they were composed of
the ordinary bohunks of the camp, on some nights almost emptying it,
relieved him.

He was turning his attention more directly to these meetings in the
woods, when something happened to alter his plan.

CHAPTER XX

INDIAN OR POLICEMAN?

The tang of the northern evening drifted through the open door of the
shack, within which the contractor lounged in his big arm chair,
smoking hard but thinking harder. Near the table, bending to let the
full light from window and door fall on her work, Tressa stitched at a
rip in a disreputable old vest of her father's.

The days were getting noticeably shorter, and the advance breath of the
long, tight winter was beginning to add a new snap to the air. The
noises of the camp drifted up over the grade fitfully, dreamily; some
new hunger that might have been called homesickness was urging a new
tone into the evening sounds.

Torrance, the stability of his work assured, imagined that he was
supremely happy. But life had lost a fraction of its zip, though he
refused to acknowledge it.

But Tressa knew it. Idleness was worse than medicine to her father,
and for days he had been fuming with impatience for the opening of the
last operation, more than a little irritable. She