From the start this time Dave knew that he had a better grasp of the mechanism than on his first trial. The Reliance behaved splendidly. Once clear of shore obstructions and sandbars, they must have run a stretch at nearly forty miles an hour. Sand Point, at the rounding end of the great lake, was reached without a mishap. Dave did not wait to try any maneuvering for a crowd that had gathered to watch the Reliance. "Straight home," he observed, as they made the turn. "It's time, I'm thinking," said Hiram. A squall had come up, and the dimness of coming eventide had already spread over the water, but there was no rain. In fact, it had turned too cold for that. A fine baffling mist was falling, however, and this was condensing into a heavy fog. "Not much to see, eh?" propounded Dave, as they got clear of the shore. "I shouldn't like to run into some stray craft." It was something of a strain on Dave, the present situation. No air signal had yet been placed on the Reliance, nor was its lighting apparatus installed. The darkness increased, and the fog became almost an impenetrable shroud. "What was that?" shouted out Hiram sharply, as there was a heavy jarring shock. "Grazed a rock, I think," replied Dave. "I don't like this a bit. If I knew my bearings, I'd run straight ashore." "Do it, anyway, Dave," advised Hiram. "We don't want to wreck the Reliance on her first trip." Dave gave the wheel a turn. Just then a distinct yell rang out across the muggy waters, and then, in rapid succession, seven quick, snappy explosions. CHAPTER VII A RESCUE IN THE FOG "What do your suppose that was?" inquired Hiram excitedly. "It was kind of startling," said Dave. "Listen." With the power shut off, the hydroplane drifted, Dave checking its slack running. They were now in a dense fog; with night fast coming on. For the moment everything was still. Then there rang through the misty space one word: "Help!" "It was in that direction," said Hiram quickly, pointing. "I think so, too," nodded Dave, "and not far away." "What could have happened? Those shots?" "Probably fired to call assistance." "If you could speed up the hydroplane a little--" "I would have to get the starter in use, and we might run into something. Hello! Hello! Hello!" Dave shouted loudly. There was a speedy reply. "Here! Hello! this wa-aa-ay!" "That's a man's voice, and he's right near to us," declared Hiram, leaning forward and peering through the mist. "Hey, there!" "I see you. Good!" There was a tilt of the machine. The person in the water had seized one of the wing stays. "Careful, there," ordered Dave. "Don't cling to that wing or bear it down." "I can't hold out." Dave cautiously edged from his seat towards a form now plainly visible. It was that of a man about thirty years of age. It was no easy task to take the man aboard. One of his hands was useless. He seemed in pain and half choked with water he had swallowed.