But the fire was now too hot to enable much to be done in the way of salvage.  One or two small things were carried out from a little addition to the main structure, and then the rescuers were driven back by the heat of the flames, as well as by the rolling clouds of black smoke.

“Keep away!” warned Mr. Swift.  “It will explode soon.  Keep back!”

“That’s right!” added Mr. Damon.  “Bless my powder-horn!  We may all be going sky-high soon, and without aid from any of Tom Swift’s aeroplanes, either.”

Warned by the aged inventor, the throng of men began slowly moving away from the immediate neighborhood of the blazing shed.  Though it may seem to the reader that some time has elapsed since the first sounding of the alarm, all that I have set down took place in a very short period—­hardly three minutes elapsing since Tom and the others came rushing out of the aerial warship building.

Suddenly a cry arose from the crowd of men near the red shed.  Ned, who stood ready with several lines of hose, in charge of Koku, Eradicate and others, to turn them on the airship shed, in case of need, looked in the direction of the excited throng.

The young bank clerk saw a strange sight.  From the top of the dirigible balloon shed a long, black, cigar-shaped body arose, floating gradually upward.  The very roof of the shed slid back out of the way, as Tom pressed the operating lever, and the dirigible was free to rise—­as free as though it had been in an open field.

“He’s going up!” cried Ned in surprise.  “Making an ascent at a time like this, when he ought to stay here to fight the fire!  What’s gotten into Tom, I’d like to know?  I wonder if he can be—­”

Ned did not finish his half-formed sentence.  A dreadful thought came into his mind.  What if the sudden fire, and the threatened danger, as well as the prospective loss that confronted Tom, had affected his mind?

“It certainly looks so,” mused Ned, as he saw the big balloon float free from the shed.  There was no doubt but that Tom was in it.  He could be seen standing within the pilot-house, operating the various wheels and levers that controlled the ship of the air.

“What can he be up to?” marveled Tom.  “Is he going to run away from the fire?”

Koku, Eradicate and several others were attracted by the sight of the great dirigible, now a considerable distance up in the air.  Certainly it looked as though Tom Swift were running away.  Yet Ned knew his chum better than that.

Then, as they watched, Ned and the others saw the direction of the balloon change.  She turned around in response to the influence of the rudders and propellers, and was headed straight for the blazing shed, but some distance above it.

“What can he be planning?” wondered Ned.

He did not have long to wait to find out.

An instant later Tom’s plan was made clear to his chum.  He saw Tom circling over the burning red shed, and then the bank clerk saw what looked like fine rain dropping from the lower part of the balloon straight into the flames.