"Start the motor! Start the motor, Mr. Sharp!" cried Tom.
"I'm trying to, but something seems to be the matter."
"We're being drawn right over the fire!" yelled Mr. Damon. "It's getting hotter every minute! Can't you do something?"
"You take the wheel," called the balloonist to Mr. Damon. "Steer around, just as if it was an auto when we start the engine. Tom, come here and give me a hand. The motor has jammed!"
The young inventor sprang to obey. Mr. Damon, his face showing some of the fear he felt, grasped the steering wheel. The airship was now about a quarter of a mile high, but instead of resting motionless in the air, sustained by the gas in the container, she was being pulled forward, right toward the heart of the mass of black vapor, which it could now be seen was streaked with bright tongues of flame.
"What's making us go ahead, if the motor isn't going?" asked Tom, as he bent over the machine, at which the aeronaut was laboring.
"Suction—draught from the fire!" explained Mr. Sharp. "Heated air rises and leaves a vacuum. The cold air rushes in. It's carrying us with it. We'll be right in the fire in a few minutes, if we
