There was a faint, damp puff of wind in their faces. Then it passed over them and gradually the shore line was blotted from sight. Around them fell a gray blanket of mist. Twenty feet away in any direction the eye lost itself in the fog. _The Dart_ slowed down and the triumphant whirr of the screw died away to a timid thudding. The engine clicked feebly and the rods at the sides of the cylinders moved up and down as though grown suddenly weary. “Harry, get busy with your horn,” directed Gerald. “Kendall, you crawl along to the bow and keep your eyes peeled. If you see anything, even a log of wood, yell back to me. We’ll be home in half an hour or so now, but I don’t want to run down a Fall River steamer or anything like that. It’s awfully bad for your paint!” At intervals Harry turned the crank of the patent fog-horn and a lugubrious wail arose to lose itself in the impenetrable mist. Between times, from various directions, far and near, came similar sounds. Save for these warnings the silence was deep. What breeze there had been was scarcely perceptible, although the bank of fog was not stationary, but moved constantly across them toward the mainland. Once or twice its grayness was tinged with amber as, for a moment only, the sun came through the clouds above. Kendall, seated at the forward end of the cabin roof, strained his eyes into the blank wall ahead. Ten minutes passed. From somewhere off the bow came the faint shriek of a locomotive. “Can’t be far out now,” observed Gerald. “Can you see anything, Kendall?” “Not a thing, but――I think I hear something.” “So do I. Get busy with that horn, Harry!” And Gerald, seizing the whistle pull, sent a series of frantic blasts into the air that so surprised Kendall that he almost fell overboard. Then Harry worked the horn again, and after that they listened intently. From somewhere ahead came the loud beat of an engine. Then a hoarse shriek broke the silence. “She’s a steamer,” muttered Gerald, “and a big one, I guess.” Again he sent the short, sharp peals of the whistle into the air. Now they could hear the beat of the propeller on the approaching steamer. Again her fog-horn tore the silence asunder. “She’s right on us!” cried Harry, grinding frantically at the crank. Gerald, standing at the wheel, peering forward, worked desperately at the whistle pull and jammed a lever over. _The Dart_ lost headway, slowed, stopped. The loud throb of the steamer’s screw seemed all about them. Uncertainly, Gerald started _The Dart_ forward again, turning her nose to starboard. Then, as another hoarse bellow came to them, he stopped the launch as suddenly and pulled the lever to reverse. The launch began backing away, circling slowly, to an accompaniment of hysterical shrieks of the whistle and agonized groans of the fog-horn. “Come back here, Kendall!” called Gerald, and Kendall scurried for the cockpit. There was a sudden _swash_ as of a wave running up a beach, and then――――