"All aboard!" cried Freddie, as they went on the small steamer that was to take them to Mount Vernon. "All aboard. I'm the fireman!"
"There aren't any fires to put out," said, Nell, teasing the small chap a little.
"Yes, there is—a fire in the boiler, and it makes steam," said Freddie, who had often looked in the engine room of steamers. "But I'm not that kind of fireman. I put out fires. I'm going to be a real fireman when I grow up," he added.
Soon they were comfortably seated on board the boat, which after a bit moved out into the Potomac. Mr. and Mrs. Bobbsey were talking together. Nan, Bert, Billy and Nell were watching another boat which was passing, and Flossie was near them. But Freddie had slipped away, in spite of what Bert had said about going to keep a watchful eye on his small brother.
Suddenly, when the steamer was well out in the river, there was the loud clanging of a bell, and a voice cried:
"Fire! Fire! Fire!"
At once every one on the boat jumped up. The women looked frightened, while the men seemed uncertain what to do.
"Clang! Clang! Clang!" rang the fire alarm bell.