"Torpedo tube ready!" reported the torpedo master through the tube from the forward torpedo compartment. By this time I had the periscope submerged so that we were completely below the surface and out of sight, and it would be impossible to discover us from the steamer, even after the most careful searching of the horizon. "Advance on the enemy!" was our determination. Oh, what a glorious sensation is a U-boat attack! What a great understanding and coöperation between a U-boat and its crew--between dead matter and living beings! What a merging into a single being, of the nerves and spirits of an entire crew! "Just as if the whole boat is as one being," was the thought that passed through my mind when I, with periscope down, went at my antagonist, just like a great crouching cat with her back bowed and her hair on end, ready to spring. The eye is the periscope, the brain the conning tower, the heart the "Centrale," the legs the engines, and the teeth and claws the torpedoes. Noiselessly we slipped closer and closer in our exciting chase. The main thing was that our periscope should not be observed, or the steamer might change her course at the last moment and escape us. Very cautiously, I stuck just the tip of the periscope above the surface at intervals of a few minutes, took the position of the steamer in a second and, like a flash, pulled it down again. That second was sufficient for me to see what I wanted to see. The steamer was to starboard and was heading at a good speed across our bows. To judge from the foaming waves which were cut off from the bow, I calculated that her speed must be about sixteen knots. The hunter knows how important it is to have a knowledge of the speed at which his prey is moving. He can calculate the speed a little closer when it is a wounded hare than when it is one which in flight rushes past at high speed. It was only necessary for me, therefore, to calculate the speed of the ship for which a sailor has an experienced eye. I then plotted the exact angle we needed. I measured this by a scale which had been placed above the sights of the periscope. Now I only had to let the steamer come along until it had reached the zero point on the periscope and fire the torpedo, which then must strike its mark. You see, it is very plain; I estimate the speed of the boat, aim with the periscope and fire at the right moment. He who wishes to know about this or anything else in this connection should join the navy, or if he is not able to do so, send us his son or brother or nephew. VI--SCENE OF TERROR AS THE SHIP GOES DOWN