At this hour of the night, however, there were none passing save Naval officers on duty. None other than the lieutenant himself had lately passed in the corridor. How, then, had this electric light bulb been shattered and made to give forth the sound of the explosion? "It wouldn't go up with a noise like that," murmured the lieutenant to himself. "These tungsten lights don't explode like that, except when rapped in some way. They don't blow up, when left alone. At least, that is what I have always understood." So the puzzle waxed and grew, and Lieutenant Adams found it too big to solve alone. "At any rate, I've questioned all the young gentlemen about the window episode, and they all deny knowledge of it," Lieutenant Adams told himself. "So I'll just report that fact to the O.C., and at the same time I'll tell him of the blowing up of this tungsten light." Two minutes later Lieutenant Adams stood in the presence of Lieutenant-Commander Henderson, the officer in charge. "So you questioned all of the midshipmen who might, by any chance, have entered by a window?" asked the O.C. "Yes, sir." "And they all denied it?" "Yes, sir." "Did you see signs of any sort to lead you to believe that any of the midshipmen might have answered in other than the strict truth?" continued the O.C. "No, sir," replied Lieutenant Adams, and flushed slightly, as he went on: "Of course, sir, I believe it quite impossible for a midshipman to tell an untruth." "The sentiment does you credit, Lieutenant," smiled the O.C. Then he fell to questioning the younger discipline officer as to the names of the midshipmen whom he had questioned. Finally the O.C. came to the two names in which the reader is most interested. "Darrin denied having been out after taps?" questioned Lieutenant-Commander Henderson. "He did, sir." "Did Mr. Dalzell also deny having been out of quarters after taps?" "He did, sir." Lieutenant Adams answered unhesitatingly and unblushingly. In fact, Lieutenant Adams would have bitten off the tip of his tongue sooner than have lied intentionally. So firmly convinced had Adams been that Dan was about to make a denial that now, with the incident broken in two by the report of the tungsten bulb, Lieutenant Adams really believed that had so denied. But Dan had not, and had Dave Darrin been called as a witness he would been compelled to testify that Dan did not deny being out. The explosion of the tungsten bulb was too great a puzzle for either officer to solve. A man was sent with a new bulb, and so that part of the affair became almost at once forgotten. Dan finally fell into a genuine sleep, and so did Dave Darrin. In the morning Dave sought out Midshipman Farley to inquire to whom the doughface should be returned. "Give it over to me and I'll take care of it," Farley replied. "Say, did you hear a tungsten bulb blow up in the night!" "Did It" echoed Darrin devoutly. Then a sudden suspicion crossed his mind.