This subterranean labyrinth of roads was similar to the yard of a great railroad center. Men were in every direction, turning switches, coupling cars, clearing tracks, etc.
Their train was taken about a mile underground, and then run into a great iron tunnel. A peculiar sighing sound, like that of a great storm a long distance off, now fell upon his ears. Turning inquiringly to Rawolle, he asked the meaning of it.
“Air—sucking air,” was the answer.
“Yes; I presumed as much,” Cobb returned, piqued at the brevity of the answer.
“Observe all you can, Mr. Cobb, for you have but a few minutes more. I will explain it after we are in the car,” noticing the impatience of the other.
The tunnel in which they then were was, like the great lower chambers, well lighted up. At one side, and opposite to where they stood, was a recessed chamber containing what appeared to be very powerful machinery. Cobb saw the motor disconnect from the train at this point, but he was not permitted to notice further the working of this most remarkable invention, for the guards ordered them into the car, and the door was closed and bolted.
Going back to the smoker, they lighted their cigars and settled themselves comfortably among the cushions.
“Now,” exclaimed Rawolle, sending up a cloud of smoke, “now I am at your service.”