"The indicator shows that the submarine is turning," said the captain. The boys watched the indicator; it had swung around almost half-way. "There,--look at the inclinometer," said Ralph. "It is moving upward----" "Ting! ting!" Two more sharp bells forward. The cylinder was off the torpedo, and it lay before them exposed. Three bells more; and now there was feverish haste. An oval door in the wall ahead was swung open, revealing a round, black hole. "That is the torpedo tube," said the captain quietly. The torpedo was moved back three feet, and then again carried forward on its truck so that the end of the torpedo entered the tube. One bell more. The torpedo moved into the tube, the breech block, which in this case was the oval door, closed, and the crew stood at attention. While thus waiting the boys glanced at the inclinometer and at the direction indicator. "See it swing back and forth," said Alfred. "It seems to act queerly." "Not at all," replied the captain. "Evidently we are chasing a ship which is zig-zagging, as we did, for the direction dial is constantly moving." While thus conversing they were startled by the signal of four bells. One of the men, reaching forward, touched a button, and the signal could be heard in the conning tower. That was, evidently, to inform the commander there that all was in readiness. Everything was expectancy now. The ship still manoeuvered. Then, without a warning of any kind, there was a singular dull sound, which seemed to shake the submarine from stem to stern. "They have fired it," said Alfred. "And they are putting in another one." "If I am not mistaken it is the last one they have," suggested the captain. "Why do you think so?" asked Alfred. "I notice that all the cylinders with the open ends are without torpedoes, and you will notice that the one they are now putting in is the last one with the closed end," responded the captain. "I am glad they haven't any more of them," said Ralph. Three bells again sounded; the officer at the gun responded, and during the next two minutes of suspense, the boys were quiet, waiting for the next shot. It soon came; the ship shook as before, the breach block opened, the shell behind the torpedo was extracted, the door closed and the men stood at attention. When the officer, who had handled the torpedoes, walked down the steps from the conning tower, the boys noticed him shake his head sadly. "Did you notice that?" asked the captain. "Do you mean the way he shook his head?" said Alfred. "Yes; I am curious to get your views about that action of the officer," remarked the captain. "That is, why he shook his head?" interjected Ralph. "Yes," answered the captain. "Do you think he looked discouraged because the shot failed in its mission, or because it went home successfully? That is the problem."