now it had completely vanished, merely a few little pools of water remaining in depressions on the bottom of the channel. There were steps leading down to the bottom, and other steps ascending on the other side, showing that the river was used as a barrier to further progress along the tunnel.
"Forward!" cried Tom gaily, and they went on.
They went down into the river channel, taking care not to slip on the wet steps, and a few seconds later they had again ascended to the tunnel, pressing eagerly on.
Straight and true the tunnel ran through the darkness, the only illumination being their electric flash lamps. On and on they went, hoping every minute to reach their goal.
"Dish suah am a mighty long tunnel," remarked Eradicate. "Dey ought t' hab a trolley line in yeah."
"Bless my punching bag!" cried Mr. Damon, "so they had! Now if those ancients were building to-day"
He stopped suddenly, for Tom, who was in the lead, had uttered a cry. It was a cry of joy, there was no mistaking that, and instinctively they all knew that he had found what he had sought.
All confirmed it a moment later, for, as they
