"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 can't get started with this motor! I don't see what ails it."
"Can't we steer to one side, as it is?"
"No. We're right in a powerful current of air, and steering won't do any good, until we have some motion of our own. Turn the gasolene lever on a little more, and see if you can get a spark."
Tom did so, but no explosion resulted. The twenty cylinders of the big engine remained mute. The airship, meanwhile, was gathering speed, sucked onward and downward as it was by the draught from the fire. The roaring was plainer now, and the crackling of the flames could be heard plainly. The heat, too, grew more intense.
Frantically Tom and Mr. Sharp labored over the motor. With the perverseness usual to gas engines, it had refused to work at a critical moment.
"What shall I do?" cried Mr. Damon from his position in the pilot house. "We seem to be heading right for the midst of it?"
"Slant the elevation rudder," called Tom. "Send the ship up. It will be cooler the higher we go. Maybe we can float over it!"
"You'd better go out there," advised Mr. Sharp. "I'll keep at this motor. Go up as high as you can. Turn on more gas. That will elevate us, but maybe not quick enough. The gas doesn't generate well in great heat. I'm afraid we're in for it," he added grimly.
Tom sprang to relieve Mr. Damon. The heat was now intense. Nearer and nearer came the Red Cloud to the blazing forest, which seemed to cover several square miles. Great masses of smoke, with huge pieces of charred and blazing wood carried up by the great draught, circled around the ship. The Red Cloud was being pulled into the midst of the fire by the strong suction. Tom yanked over the elevation rudder, and the nose of the craft pointed upward. But it still moved downward, and, a moment later the travelers of the air felt as if they were over a fiery furnace.