Southward lay Plum Island, seven miles distant, and beyond it the main shore of Long Island was hazily visible. To the southeast, in clear weather, one could see Montauk Point, but to-day it was hidden by a fog bank. There were numerous sailing craft in sight, and an excursion steamer, well loaded with passengers, passed down the Sound a half mile away, an occasional blare of music from her band reaching them on the breeze. There was very little sea to-day and The Dart sped along on an almost even keel. And how she did go! Fourteen miles, said Gerald, but it seemed to Kendall that it must be more than that. Gerald, from where he sat at the wheel in the cockpit, could look along the roof of the cabin and had a clear view of the course. Everything for the control of the launch was within reach, spark, throttle, clutches and a strident electric whistle.

“It’s just like an automobile, isn’t it?” said Harry with a sigh of envious admiration.

“It’s better,” laughed Gerald. “There aren’t any tires to blow out!”

Kendall perched himself in the stern where he could watch and enjoy the rush of the green water. Harry stretched himself along the cabin roof. “Are you going all the way across?” he asked.

Gerald shook his head. “No, I’m going to turn in a few minutes and run up toward Fishers Island. There’s fog over there and I don’t want to get caught in it. We’re three or four miles out now, I guess.”

When, presently, The Dart turned her head eastward the breeze was less apparent. For a moment the sun broke through and the waters of the Sound took on new shades of paler green as they broke past the stern. But the clouds soon closed again. Harry, lying against the low handrail at the edge of the cabin roof, showed an inclination toward slumber. Gerald and Kendall chatted of a hundred things while the launch shot her way steadily and swiftly along. Fishers Island grew larger and nearer. A four-masted schooner lazily dipped by and a long, low torpedo destroyer, her battleship-gray hull scarcely distinguishable from the sullen water, steamed toward the mouth of the Thames River, probably on her way to the Navy Yard above New London. Suddenly a slight exclamation from Gerald brought Kendall’s attention back from the wicked-looking craft. Gerald was gazing southward in surprise. All vestige of Long Island was gone and a bank of gray fog was advancing across the Sound.

“I don’t like that,” muttered Gerald, and The Dart circled rapidly and shot away toward home. The sudden turn disturbed Harry’s dreams and he looked down at the others, blinking inquiringly.

“What was that? Who shoved me? I say, Gerald, look at the fog out there, will you? Hadn’t we better beat it?”

“We’re beating it now,” answered Gerald grimly, advancing the throttle lever a little. The steady whirr of the propeller increased and there was a louder sound from the engine below. “Take the wheel a minute, Kendall, while I douse some oil. Hold her just as she is.”

Kendall scrambled over and gripped the rim of the wheel, while Gerald stepped into the cabin and poked around with a long-nosed oil-can. The Dart was headed straight back for Wissining, but there was a good five miles ahead of her and the fog-bank was rolling in fast. Kendall viewed it apprehensively, without realizing just what it meant. It moved toward them steadily, inexorably. At first nearly a mile away, now it was less than half that distance. While he looked a sloop, beating toward Orient Point, grew suddenly faint to view, then disappeared utterly from sight. Gerald came back and took the wheel.

“We’ll be in it in another five minutes,” he said. “Hustle down, Harry, and dig the fog-horn out of that after locker. That’s it. Know how to work it? Just turn the handle around as though you were churning ice cream or grinding coffee.”

Harry obeyed and a most dismal bellow was emitted from the box. “Isn’t it sweet?” laughed Harry. “Want me to do it again, Gerald?”

“Not yet. Put it up on the roof and when the fog hits us give her a turn every half minute or so.”

“How far from home are we?” asked Gerald, looking down the shore.

“Oh, three miles or so. She’s making a good sixteen miles now, but I’ll have to bring her down to four or five in a minute or two. Here she comes, fellows!”

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——

“Hold on hard, fellows!” shouted Gerald, twirling the wheel.

To the right, off the port bow of the launch, a hulking shadow took shape, a shadow that loomed high above the water and broadened instantly into the black bow of a steamer. Somewhere up there a voice shouted and was drowned in the roar of the whistle. For a long moment the three boys cowering in the cockpit of the launch, frozen into silence, neither spoke nor moved. Then Gerald seized a cushion from a seat and thrust it at Kendall.

“Hold tight to that and jump,” he cried. “Quick.”