into the engine room, which, like the other parts of the cabin, was now murky with choking vapor and soot.
Suddenly the elevation gauge showed that they were falling. The airship was going down.
"What's the matter?" called Mr. Damon, from the cabin floor.
"I don't know," answered Tom, "unless the rudder has broken."
He peered through the haze. No, the big elevation rudder was still in place, but it seemed to have no effect on the ship.
"It's a down draught!" cried Mr. Sharp. "We're being sucked down. It won't last but a few seconds. I've been in 'em before."
He seemed to have guessed rightly, for, the next instant the airship was shooting upward again, and relief came to the aeronauts, though it was not much, for the heat was almost unbearable, and they had taken off nearly all their clothing.
"Lighten ship!" sung out Mr. Sharp. "Toss over all the things you think we can spare, Tom. Some of the cases of provisions! We can get more—if we need 'em. We must rise, and the gas isn't generating fast enough!"
There was no need for the young inventor at the steering wheel now, for the craft simply could not be guided. It was swirled about, now this
