"There is only one way for him to get out, and it is not a pleasant way. But in his nightmares he has often rehearsed it, and he has always made sure that it could be done before he went to sea. There must always be a way out for one man at least, if not for more. '_L'état, c'est moi!_' "He beckons to the little Bavarian. 'I have all the diamonds in my pocket,' he says. 'The time is come for you to help me, Otto.' "Now, Roy, you know what the conning tower of a submarine is like inside? It is like a round chimney, with a lid at the top to keep out the water when you are submerged. You can climb up into this conning tower and steer the ship from it if you wish. There is also another lid at the bottom of the conning tower, which you can close as well. Then if you wish you can flood your chimney with water. "Now, if a submarine cannot rise to the surface, it is possible for a man to climb into this conning tower. Another man then closes the lid below and floods the tower very slowly. When the water reaches the head of the man in the tower there is just enough pressure for him to push open the lid at the top and shoot up to the surface. The lid at the top can then be closed from the interior of the submarine. The lower lid can be opened slowly, and the water from the tower pours out into the hull. Then, perhaps, another man can climb up into the tower, and the process can be repeated. There is room for only one man at a time. "The captain tells the little Bavarian that he is going to do this. 'But, my captain, it is very dangerous. You may be drowned. It is not certain that you can open it. The pressure may be too great above.' "'It is for the Fatherland, Otto,' says the captain; and the little Bavarian salutes, standing at attention, just like a pretty little wax doll. "'When the men wake, you will be able to follow by the same road,' says the captain, and he climbs up into the conning tower. "The lower lid is closed. The water begins to creep up round the captain's knees in the darkness. He is horribly frightened. He has a crowbar in his hand to help him to open the upper lid quickly, but he still thinks perhaps it will not open. When the water has reached his waist he begins to push at the upper lid, but it cannot move yet. The weight of the whole sea above is pressing down. He knows it cannot move but he cannot help pushing at it, till the sweat breaks out on him, though the water is like ice. It is worse than he expected, worse than any of his nightmares. The water reaches to his neck. He struggles with all his strength, and still the lid will not move. A prayer comes to his lips. The cold water creeps--creeps over his chin. There is only three inches now between his face and the lid. He holds his head back to keep his nostrils above the water, fighting, fighting always to open the lid. Then the water covers his face. The conning tower is full.