“Now, my friend,” said Alan, turning to Alexis as soon as they were alone again, “what is your plan?”
“Simply this,” replied Alexis. “Mount Terror, or at any rate the mouth of the submarine tunnel, is in round numbers three thousand geographical miles from here. Our speed is thirty miles an hour faster than that of Olga’s squadron. That means that even if they go back at once and at full speed we shall be there four or five hours before them.
“They, I think, have had quite enough fighting for to-day, and I don’t believe they’ll attack the island again—first, because they know that they can’t take our sea defences by surprise, and, second, because they think the Narwhal will remain on guard.
“Either they will go off on a raiding expedition somewhere else with the air-ships—in which case we can’t follow them, for we don’t know where they’re going—or they will return to Mount Terror at an easy speed of fifty or sixty miles an hour. They will never dream that you and I will venture to attack the stronghold single-handed, and, therefore, that is just what I propose to do.”
“That will be odds of about forty to one against the Narwhal,” replied Alan, somewhat gravely. “Unless we can destroy it completely before they get back. But go on. Let’s hear the rest. I don’t think you can propose anything too desperate for me now that I have really tasted the blood of the enemy.”
“Well, what I propose is not to destroy the stronghold, simply because it would be impossible to do that by sea. I merely propose to get quietly into the tunnel, go to that narrow part about two miles from the entrance, fix a dozen torpedoes with time-fuses up against the roof of the tunnel, and then clear out into the open water.
“When those twelve torpedoes go off if they don’t bring a few thousand tons of rock down into the tunnel and block it pretty securely I’ll grant I know very little about explosives.”
“Good so far, very good!” said Alan. “I confess I envy you that idea. What next?”
“Well, after that,” replied Alexis. “You see we shall have shut in the vessels that are inside and shut out those that are outside. The ones inside will be no use for some time, for it will take the divers a good many days to open the tunnel again, even if they ever do.