"Now I'll be able to show you some pretty sights, Mr. Hardley," said Tom, as he and his friends entered the forward compartment, while the steel shutters were rolled back from the heavy glass windows. "We'll be in deep waters presently."
Ten minutes later the depth gauge showed that they were down about three hundred feet, and that is pretty deep for a submarine. But Tom's boat was capable of even greater depths than that.
At first there was nothing much to observe save the opal-tinted water illuminated by the powerful lights of the submarine. Small, and evidently frightened, fish darted to and fro, but there was nothing especially to attract the attention of Tom and his friends, who had made much more sensational trips than this under water.
Mr. Hardley, however, was fascinated, and kept close to the observation windows.
"Are there any wrecks around here?" he asked Tom.
"Possibly," was the answer. "Though they do not contain any treasure, I imagine—brick schooners or cargo boats would be about all."
The submarine went deeper, plowing her way through the Atlantic at a depth of more than three hundred and fifty feet, for Tom wanted to subject her to a good test.
Suddenly Mr. Hardley, who was now alone at the window on the port side, uttered a cry of alarm.
"Look! Look!" he fairly shouted. "We're surrounded by a school of sharks! What monsters! Are we in danger?"