There was no doubt that the steamer was coming after the submarine. Several observations Captain Weston made confirmed this, and he reported the fact to Mr. Swift.
"Well, we'll change our plans, then," said the inventor. "Instead of sailing on the surface we'll go below. But first let them get near so they may have the benefit of seeing what we do. Tom, go below, please, and tell Mr. Sharp to get every thing in readiness for a quick descent. We'll slow up a bit now, and let them get nearer to us."
The speed of the submarine was reduced, and in a short time the strange steamer had overhauled her, coming to within hailing distance.
Mr. Swift signaled for the machinery to stop and the submarine came to a halt on the surface, bobbing about like a half-submerged bottle. The inventor opened a bull's-eye in the tower, and called to a man on the bridge of the steamer:
"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.