Bob knew there was an answer to the problem, and it was probably something ridiculously simple, but it evaded his every mental effort and he finally turned to the comic page of the newspaper for a chuckle or two at the antics of the comic characters. The other passenger in the car put down the magazine he had been reading and went forward to his berth in another car. Bob was alone in the observation lounge without even a trainman in the car. From up ahead the dismal hoot of the locomotive whistle drifted back and seconds later the car lurched as the trucks crashed over the frogs of a siding and the dimmed lights of a village drifted by in the storm. Then the train was in the heart of the desolate night once more. After the events of the afternoon, with Tully’s sudden collapse and the disappearance of Hamsa, it was not a scene to inspire confidence in the heart of any young federal agent and Bob felt a queer chill running up and down his spine. Once or twice before, when sudden danger impended, he had had the same feeling. Some premonition caused Bob to turn quickly toward the forward end of the observation car and his eyes riveted on a hand, extended around the edge of the corridor, which was groping for the switches controlling the lights inside the car. Bob was motionless, but for only a second. Then he leaped forward, his powerful legs driving him ahead as the groping hand finally found the switch and he saw the fingers tense as they started to move the lever downward which would plunge the car into darkness. A blanket of darkness engulfed the interior of the observation car and Bob heard the faint click of the switch. His body was hurtling forward with a momentum impossible to stop and he crashed almost headlong into the steel partition at the end of the car. Bob was dazed by the shock of the impact and he dropped to the floor, too bruised to move for a moment. Then a finger of light sought him out. The tiny ray was almost blinding in its brilliance and the beam swept Bob’s face as he struggled to get up. He was on his knees and facing the mysterious beam when there was a sharp blow on his face. The impact was not hard, but there was no mistaking that he had been struck. A sudden nausea swept Bob and he felt his power of control ebbing rapidly. He tried to cry out, but his tongue seemed to swell and stick in his mouth. His arms dropped at his sides and he felt his knees wobbling. In spite of everything he could do he collapsed on the floor of the observation car. The last thing Bob remembered was the thin beam of light which still sought him out with relentless steadiness and then a mocking laugh, heavy and daring, that might easily have come from the lips of Joe Hamsa had he been on the Southern Limited. Chapter XI DOUBLE DANGER ★