His ammunition would not last if this kept up.

“Get busy, Shea!” he cried.  “Find something and slap at the fire for all you’re worth!  Fight it, man, fight it!”

As Frank happened to turn his head to learn what the other was doing he saw something that made very little impression on his mind just then, but which had considerable bearing on the matter later.

A light was speeding along the road, heading away from town, and Frank realized that the firebug had seized upon his convenient wheel and was making his escape.

Later on he might figure out the meaning of this movement.  Just then he really had no time to give it a thought, no matter if a dozen wheels were concerned.  The fire demanded every atom of his attention.

Shea did get busy.  Once he became stirred up, and he proved a valuable helper.  He went for the flames tooth and nail, smothered them with his coat, regardless of consequences, after he had slipped that article of wearing apparel off; kicked and tore and fought until it became evident that between them they were certainly making a decided impression on the threatening conflagration.

All this while it seemed to Frank that his heart was in his throat.  Not so much because he feared that they would fail to gain the mastery over the fire as that some spark might find ingress to the shed and happen to alight upon a can of the dangerous gasoline.

If such a thing occurred he knew that it would be all over.  The hangar must be completely destroyed and, of course, their little darling airship would share in its fate.

So, even though he saw the end of the conflagration in sight, Frank knew he had no reason to breathe easily until every spark had been trampled under foot.

By now he was conscious of loud shouts coming from points near at hand and realized that doubtless Andy as well as others had been awakened by the racket and were coming on the run to assist.  Had the safety of the airship depended on their reaching the shed in time, though, its chances would have been next to nothing.

Frank was just stamping on what seemed to be the very last vestige of the fire when Andy came galloping to his side.

“W-what’s all this mean, Frank?  Where in the wide world did you come from, and who set our hangar afire?” he gasped, almost winded from his exertions, for he had dressed in about a minute, despite his trembling fingers, and was barefooted even then.

“Don’t know who did it, but he ran off on my wheel a few minutes ago.  I was on the way home—­carrying medicine to Susie Lovejoy.  Saw flames and gave alarm.  Got here on the jump and we managed to get the better of it.  But it was a close shave, all right, I tell you, Andy!”

Frank himself had no breath to spare, nor could it be wondered at, considering the recent valiant fight which he had made against big odds.

“So the ornery skunks did try to burn us out, after all!” burst forth the other part owner of the monoplane, bitterly.  “Say, where was Shea all this time?  What use was he as a watchman?”