"If we could only film it!" added Charlie, his voice and that of his chum ringing hollow in the tunnel.
"We'd stand about as much chance as we did when the volcano let loose in Earthquake Land," answered Blake. "Come on, fellows! This isn't over yet."
"I only hope we don't run into a party of Huns who'll drive us out," murmured Joe.
But, so far, they had met no one, though ahead of them they could hear a sound as though others were running through the underground shaft seeking a place of safety.
"Where are we going, anyhow?" asked Charlie at length.
"Going until we stop," answered Joe.
"And that'll be soon," added Blake, "for I see the last of the lights."
The boys looked down the long passage, which was well made and was high enough to permit them to run upright. It was wide enough, also, for three to go abreast. As Blake had said, the string of incandescent lights, suspended overhead, came to an end a little farther on. They stopped under the third light from the last and looked about them.
"Isn't this as good a place as any?" asked Joe. "If we go on any farther we may get into a hole we can't get out of. I say, let's stay here. We'll be safe from the airship bombs."
"I don't know about that," said Blake. "If you'll notice, we have come along pretty much on the level. This tunnel wasn't dug in the side of a hill. It went into the ground slanting, and at such a gradual slope that the top can't be very far under the surface."