Now that you have seen the weapon--and can at any rate imagine the handling of it--you are naturally keen to sight the game, and realise the conditions of a good shot. You go back to the central compartment, where the Commander is ready to show you a ship through the periscope. Not, of course, an enemy ship--in this war, if you want a shot at an enemy ship, you must go into his own waters--into the Bight or the Baltic--to find him; and even there he is probably tucked up very tight in his berth, with chained barges and heavy nets all round him, and mines all up the approach. But there are plenty of our own ships out every day--sweeping, cruising, trading; and transporting men, food, mails, and munitions. And what you see will help you to understand why the Germans have spent so many torpedoes, and sunk so comparatively small a proportion of our enormous tonnage. The boat is now less deep in the water; the gauges mark 15 feet, and you are told that the top of the periscope is therefore some two feet above the surface. The shaft of it is round, like a large vertical piston; but at the bottom it ends in a flattened box, with a hand-grip projecting on each side. You take hold of the grips and look into the box. Nothing is visible but an expanse of water, with a coast-line of low hills beyond it--all in miniature. The Commander presses the back of your left hand on the grip, and you move round slowly as the periscope revolves. The coast-line goes out of the picture, the sea lies open to the horizon, and upon it appears a line of odd-looking spots. They are moving; for the nearest one, which was narrow a moment ago, is now three or four times as broad, and is in a different place in the line.