"How far are they from us?" asked Alfred.
"Two miles!" said Ralph in astonishment. "Why, I thought I was stretching it when I said a half mile."
"To be more exact, the range finder in the crow's nest makes the distance 10,980 feet," said the captain.
"Well, they can't hit us at that distance," said Ralph, "can they?"
"No; we can easily avoid that fellow, but he may have appeared as a ruse," said the captain, glancing to starboard, with an anxious air.
The first officer standing near, although intently watching the submarine in the distance, remarked: "It is now the custom for two or more of the undersea boats to operate in unison; the one we are now looking at may be a decoy."
"What do you mean by 'decoy'" asked Ralph, in astonishment. "Is it likely that they would expect us to steer right into them?"
"No; their idea is to have one of the submarines show up in front, knowing that the intercepted vessel will turn to avoid it. Then the other submarine, with nothing but its periscope above the water, and on the other side of the sailing course of the ship, will be in position, the moment the turn is made, to deliver the shot. That is why the captain has gone to the other side, as you will notice the vessel is now going to starboard," said the officer.
The ship had now turned so that it was broadside to the distant submarine. Not only its conning tower was now visible, but a long black object fore and aft could be plainly observed.
"Three points to port!" shouted the captain.
The quartermaster swung the wheel around, and the ship seemed to heel over, so suddenly did the rudder act.
"One point to starboard, and full speed ahead!" was the next order from the captain.
It seemed that the order had no more than been executed than he again sang out:
"He is zig-zagging the ship through the sea," replied the officer.
"There is another submarine three points to starboard astern."
"Yes; the one behind us is near enough to reach us if we keep on a straight course, but the captain has manoeuvered so as to bring him directly in our wake, and continually changed the target so that the submarine cannot aim with accuracy," interrupted the officer.
The passengers on the decks below did not need to be told that something unusual was happening. The changing course of the ship, the unusual activity on the bridge, the leveling of the glasses to the port side and to the stern by the different groups, were sufficient warnings of the presence of the dread monsters.