I managed to effect a change of costume without arousing my Scottish friend. He snored harmoniously and uninterruptedly. When I returned to the deck, no trace of mist was visible. The sea looked like oil and the heat was oppressive. I lingered at the rail for a moment, staring forward to where the Cornish coast lay veiled in distance. Right ahead, I discerned a faintly moving white speck. Then I became aware of someone beside me. I turned. The Captain stood at my elbow. “No rest for me to-night, Mr. Decies,” he said. “The Channel is a mass of soup.” “So I have heard,” I replied. “What’s that ahead?” “I have been wondering,” he murmured. “It looks like a motor boat--and right on our course. Excuse me. I might as well go up.” A few minutes later, as I rejoined O’Shea, the ship bellowed her warning to the small craft ahead. O’Shea was in the operator’s room. “What’s that?” he asked. “Not fog already?” “No,” said I. “There’s some kind of boat in our way.” “Oh,” said he. “Fisherman?” “No. It looks like a pleasure cruiser.” He stared for a moment. I had never seen him look so ill groomed. His wavy hair, since he had gone hatless all night, was wildly disordered. Then the instrument began its mysterious coughing. O’Shea placed his monocle carefully in position and lighted a cigarette. The operator adjusted the headpiece. “Here it is, sir!” he said. “At last!” “Excellent,” said O’Shea calmly. And, whilst this long-awaited message came through, the horn began its disturbing solo--and mist crept, damply, into the cabin. We had struck the outer fringe of the Channel fog. At this moment I saw Nanette. She stood at the door, wide-eyed, wrapped in a furry coat. I ran out to her. “Oh!” she exclaimed, and clutched me--“where is--Major O’Shea?” She was trembling. “Nanette!” I said. “What is it? He is there--in the operator’s room.” “Thank God!” I heard her whisper. Then: “I have been so frightened!” she went on, clinging to me. “Mrs. Porter sleeps like a log--and Captain Slattery came to our room a few minutes ago and knocked. I opened the door, not realizing who it was.” “Yes?” I said, clenching my hands tightly. “He was--insane. He said--he was going to kill Major O’Shea----” “What’s that?” came in a cool voice. O’Shea stepped out on the deck. He held a slip of paper in his hand. The mist had closed down, now, like a blanket. Even the deep note of the fog-horn was muted. “I’ve got him, Decies!” said O’Shea. “What!” “He sent off two code messages before my eyes were opened; and he received one reply. I don’t know the code.” Dimly, through the fog, a queer, high siren note reached us. “Major O’Shea!” Nanette released her grip and grasped O’Shea’s arm. “Are you talking about Captain Slattery?” The Marconi operator joined our party as: