Already the horror of the murderer was in his eyes as he glanced furtively around.
[Illustration: QUEST JUMPS FROM THE SIGNAL TOWER ON TO THE FAST MOVING TRAIN.] [Illustration: A PAIR OF MYSTERIOUS HANDS PLACE THE BLACK BOX ON QUEST'S TABLE.] "I never meant to drop him," he muttered.

"I got mad at seeing Quest get off.

That man's a devil." "What are we going to do ?" the other demanded hoarsely.

"It's a quiet spot this, but there'll be some one round before long.

There goes the damned signals already!" he exclaimed, as the gong sounded in the tower.
"There's the auto," Gallagher shouted.