"There's a rowboat adrift!" exclaimed one of a group of men who stood on the edge of a large pier at Chicago's water front."Yes, and the steamer will sure smash it," added another. "She's headed right for it! It's a wonder folks wouldn't learn to tie their boats secure. Whose is it?""I don't know. It's a good boat, though. Pity to see it knocked into kindling wood.""That's right."The pilot of the big freight steamer, which was approaching her dock after a voyage down Lake Michigan, also saw the drifting boat now, and, doubtless thinking some one was in it, he pulled the whistle wire sharply. A hoarse blast from the steamer's siren came across the water. The signal was one of alarm.At the sound of it a boy, who had been sitting on a box at the edge of the wharf, idly swinging his bare feet to and fro, looked up. He was a lad about fifteen years old, with brown eyes and a pleasant face. Though clean, his clothes-what few he had on-were very much patched."Something's the matter," said the lad. "Something in the path of the steamer, I guess," for he had been around the lake front so constantly that he was a regular water-rat, and he knew what every whistle signal meant.