"All aboard, then," ordered Mr. Swift, and they went into the submarine. Tom and his father, with Captain Weston, remained in the conning tower. The signal was given, the electricity flowed into the forward and aft plates, and the Advance shot ahead on the surface.
The sailor raised his telescope once more and peered through a window in the tower. He uttered an exclamation.
"What's the matter?" asked Tom.
"That other ship—a small steamer—is weighing anchor and seems to be heading this way," was the reply.
"Maybe it's some one hired by Berg to follow us and trace our movements," suggested Tom.
"If it is we'll fool them," added his father. "Just keep an eye on them, captain, and I think we can show them a trick or two in a few minutes."
Faster shot the Advance through the water. She had started on her way to get the gold from the sunken wreck, but already enemies were on the trail of the adventurers, for the ship the sailor had noticed was steaming after them.