Shirley happened to be looking through the grimy caboose window at that moment.  On the top log of the load the object of her unhappy speculations was seated, apparently quite oblivious of the fact that he was back once more in the haunt of his enemies, although knowledge that the double-bitted axe he had so unceremoniously borrowed of Colonel Pennington was driven deep into the log beside him, with the haft convenient to his hand, probably had much to do with Bryce’s air of detached indifference.  He was sitting with his elbows on his knees, his chin in his cupped hands, and a pipe thrust aggressively out the corner of his mouth, the while he stared moodily at his feet.

Shirley suspected she knew what he was thinking of; he was less than six feet from her, and a morbid fascination moved her to remain at the window and watch the play of emotions over his strong, stern face.  She told herself that should he move, should he show the slightest disposition to raise his head and bring his eyes on a level with hers, she would dodge away from the window in time to escape his scrutiny.

She reckoned without the engine.  With a smart bump it struck the caboose and shunted it briskly up the siding; at the sound of the impact Bryce raised his troubled glance just in time to see Shirley’s body, yielding to the shock, sway into full view at the window.

With difficulty he suppressed a grin.  “I’ll bet my immortal soul she was peeking at me,” he soliloquized.  “Confound the luck!  Another meeting this afternoon would be embarrassing.”  Tactfully he resumed his study of his feet, not even looking up when the caboose, after gaining the main track, slid gently down the slight grade and was coupled to the rear logging-truck.  Out of the tail of his eye he caught a glimpse of Colonel Pennington passing alongside the log-train and entering the caboose; he heard the engineer shout to the brakeman—­who had ridden down from the head of the train to unlock the siding switch and couple the caboose—­to hurry up, lock the switch, and get back aboard the engine.

“Can’t get this danged key to turn in the lock,” the brakeman shouted presently.  “Lock’s rusty, and something’s gone bust inside.”

Minutes passed.  Bryce’s assumed abstraction became real, for he had many matters to occupy his busy brain, and it was impossible for him to sit idle without adverting to some of them.  Presently he was subconsciously aware that the train was moving gently forward; almost immediately, it seemed to him, the long string of trucks had gathered their customary speed; and then suddenly it dawned upon Bryce that the train had started off without a single jerk—­and that it was gathering headway rapidly.

He looked ahead—­and his hair grew creepy at the roots.  There was no locomotive attached to the train!  It was running away down a two per cent. grade, and because of the tremendous weight of the train, it was gathering momentum at a fearful rate.