"What are you following us for?"
"Following you?" repeated the man, for the strange vessel had also come to a stop. "We're not following you."
"It looks like it," replied Mr. Swift. You'd better give it up."
"I guess the waters are free," was the quick retort. "We'll follow you if we like."
"Will you? Then come on!" cried the inventor as he quickly closed the heavy glass window and pulled a lever. An instant later the submarine began to sink, and Mr. Swift could not help laughing as, just before the tower went under water, he had a glimpse of the astonished face of the man on the bridge. The latter had evidently not expected such a move as that.
Lower and lower in the water went the craft, until it was about two hundred feet below the surface. Then Mr. Swift left the conning tower, descended to the main part of the ship, and asked Tom and Captain Weston to take charge of the pilot house.
"Send her ahead, Tom," his father said. "That fellow up above is rubbing his eyes yet, wondering where we are, I suppose."
Forward shot the Advance under water, the powerful electrical plates pulling and pushing her on the way to secure the sunken gold.
