The cables were untied from the trees and taken aboard, the rudder tilted to pilot the Hawk skyward, the motor was started, and presently the power was switched into the propeller.
Then, just as the air ship was given a boost upward, the engine stopped dead. Without the power of the propeller behind her the car became unmanageable, and the wind, faint though it was, tossed the big gas bag against the limbs of one of the trees.
This lasted only a moment, for, as suddenly as it had stopped the engine had taken hold again, and the propeller began to whirl. Quick as a wink Matt depressed the steering rudder. The Hawk dipped downward, cleared the branches, and then was brought up to continue the climb into the air.
"A tight squeak, mate!" gasped Ferral. "Whatever was the matter with the engine?"
"Any one of a dozen things may have happened," replied Matt, "but we seem to be all right now. Come back here, Dick, and do the driving while I look over the motor."
Matt could see nothing wrong with the motor, and felt sure that, no matter what had caused the sudden failure of the engine, the trouble would not happen again.
Having finished his examination of the machinery, Matt turned his attention to the gas bag. The top of the bag, of course, he could not see, but there were no indications that anything was wrong. With a sense of relief, the young motorist returned to his post and sent Dick ahead to join Carl at the lookout.
There was something to quicken the pulses in the mere thought of venturing far out over the sea in a "dirigible." The Hawk was mistress of the air, but, if any accident happened and she was precipitated into the sea, the steelwork of the car would drag her under and bring certain death to all aboard.
But Matt and his chums had implicit confidence in the Hawk. They had sailed her over Lake Michigan, and why could they not sail her across the Florida Straits?
Carl, leaning over the rail, had a dismal thought as they left the line of white surf and headed boldly toward the heaving horizon to the east and south.