“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. “As for those outside, we can lie in wait for them if they return, and trust to the _Narwhal’s_ speed and strength to sink as many of them as we can, or else, if they don’t put in an appearance, we can come home with the consciousness that we have done about all the damage in our power. Now, what do you think?” Alan was silent for a few moments, weighing the pros and cons of the desperate venture--for desperate it was, in spite of the incomparable speed and strength of the splendid vessel he commanded. It was easy enough, always supposing that it could be accomplished without interruption; but to be caught in the tunnel, as was quite possible, between a force inside and one outside meant almost certain destruction, for if the _Narwhal_ was not rammed and sunk in a space too narrow for her to turn she would be certain to be blown up by the torpedoes which would be launched against her. In the end, the very character of the desperate venture, combined with the magnitude of the injury it would do to the enemy, overcame the scruples of his prudence. He put his hand on Alexis’ shoulder, and giving him a gentle shake, said with a laugh-- “Bravo, old philosopher! You’ve done more with your thinking than we have with our talking and writing. We’ll do it, if there isn’t a square foot of the _Narwhal_ left when the business is over.” “I knew you’d say that,” said Alexis. “Now let’s have some dinner and go to sleep, for we shall want it.” It was then very nearly midday, and the _Narwhal_ had cleared the islands, and, with her prow pointed direct for the north-eastern extremity of Wilkes’s Land, was rushing at full speed through the water about twelve feet below the surface of the sea. For twenty hours she sped silently and swiftly and unseen on her way, swept round the ice-barrier that fences the northern promontory of Victoria Land and into the bay dominated by the fiery crest of Mount Erebus. CHAPTER XIV. FROM THE SEA TO THE AIR.