Twenty minutes later I was locked in my room, charged by the excited Captain Merwin with murdering the mate. "Find the motive; find the man!" he had stormed. He had heard me threaten again through his window as he was undressing for bed, and nothing that I could say as to another man's threatening, too, had the slightest effect. His daughter had evidently seen, and had fainted from the shock. When she recovered she would, no doubt, so testify. With the boatswain standing my watch, I sat there until midnight; then, as the other boatswain relieved him, I crawled into my berth, but not to sleep. The problem would not permit it; for it was a problem that would not solve. But, in my casting about for a solution, I was forced to exonerate Bill, the only man besides myself with the "motive." For how could Bill, whom I had seen on the yard just before going below, descend to the lee alley, knife the mate through the window, and get aloft in time to answer at four bells? Mentally counting my steps along the alley and down to the passage, the half-minute or so while I was engaged at the log slate, and the succeeding interval of time between his death scream and Bill's call from aloft, I found it incredible. Even had he been able so to time his descent by any means as to reach the window before I had closed the log slate, still the men had wakened at the scream, and one or more would have seen him before he could have got out of sight behind the cro'-jack on his way aloft. As for Tom, who also had a motive, though a lesser one, he was out of the question. There were no beckets nor lanyards with which to secure the wheel, and had he dropped it the canvas would have been in ribbons before he could reach the window. The steward, who slept off the forward cabin, had come out, rubbing his eyes, palpably stupid from recent sleep; and he had no motive--the mate had liked him. When I had sprung on deck the strong moonlight had shown it clear of men as far forward as the main hatch, from which a few were arousing themselves. The murderer could not have run forward. Who else? I asked myself. Mabel? She could have run forward by the lee alley after I had gone down by the other; but why? She had no motive for the crime, and if she had why would she have chosen such a moment, when discovery was inevitable? Then, too, it required strength beyond hers to drive a sheath knife to the handle into the body of a man. No, Mabel was also out of the question; but there came to my mind the equally disquieting query, What was she doing on the main deck, or in the alley near the mate's room, at that time of night? This I could not answer; but at daylight it was answered for me. Captain Merwin opened the door of my room, and I rolled out of my berth. "Mr. Rogers," he said, "I owe you an apology. You did not kill the mate. She has recovered and explained." "Who did, sir?" I asked.