“Here is a regular underground waterway,” declared Gif presently. “It looks to be pretty deep, too.”
He was right. To the surprise of everybody they had come out upon what seemed to be an underground pond. On the side upon which they had emerged there was a small sandy slope. The other side, and the far end, were covered with jagged rocks.
The strange blowing, pounding, and clanking continued, and almost deafened the cadets. They felt that they were on the point of a great discovery, but could not imagine what it would be.
“It’s a workshop, all right enough,” declared Fred, a minute later. “Jack, put out that light, quick!” And at this command the flashlight was turned off.
The cadets had rounded a bend of the underground waterway, and now at a distance they saw a number of electric lights shining brightly. There was some machinery set up among the rocks, and several workmen were present, all seemingly busy.
“Look!” exclaimed Jack, his eyes almost starting out of his head at the sight. “What do you think of that, fellows?”
He pointed to a spot beyond where the strange men were working. There the waterway seemed to broaden and deepen, and in the water lay a strange-looking craft more than three-quarters submerged.
“It’s a submarine!” breathed Fred excitedly. “A submarine! What do you know about that?”
“A SUBMARINE! WHAT DO YOU KNOW ABOUT THAT?”