CHAPTER XXI.
DIRIGIBLE VS. AEROPLANE.
A galvanic shock passed through the boy at the discovery, and he silently crawled to where Harry and Ben lay and placing his hand over their mouths he in turn awoke them.
"Don't utter a word," he whispered, "Luther Barr's air-ship is here."
From the spot in which they crouched, keeping as closely in the shadow of the stout mast as they were able, the adventurers could hear distinctly the conversation of the men in the dirigible.
"This must be the galleon," Frank heard a voice he recognized as
Sanborn's saying, "it's lucky we decided to keep on."
"Well, we might as well have turned back for all the good we can do now," came another voice—that of Malvoise. "I'm not going to run a chance of wrecking the ship by making a landing in the dark."
"What, you are not going to descend?" came Sanborn's voice in a querulous tone.
"Not much," was the rejoinder. "What's the use of risking our necks and taking a chance on smashing up the air-ship. If she is damaged we would be stranded here and leave our bones in the Sargasso in all probability."
"That's so," chimed in another voice—that of the inventor Constantio. "It would be very dangerous, senor, to make a landing to-night. Let us go back to the island and start out to-morrow again."
The boys exchanged glances. So the Barr party had encamped on an island; doubtless one of the numerous little keys that abound in those waters and which, had they water on them—which few have—are ideal spots.
"That's my idea, Sanborn," went on Malvoise, "come, shall I put her about and sail back?"
"Let's circle the ship first," exclaimed Sanborn. "So far as we know we are here ahead of those Boy Aviator cubs, but we can't tell positively unless we make an examination."
Frank's heart stood still. If they circled the ship there was little doubt they would spy the Golden Eagle floating alongside; in black shadow though she was. His fingers closed on his revolver. But fortunately there was no need to use weapons then, for Sanborn's idea was overruled, and from the position in which the air-ship hovered she could not spy the aeroplane.
"No; come on, let's get back," urged Malvoise; "there is something wrong with one of the cylinders and I want to fix it before we tackle the job of taking off the treasure."
"Very well then," said Sanborn, yielding to the will of the majority. "We'll get back, but I want to be here first thing in the morning and make a thorough overhauling of the ship. There ought to be enough gold aboard her, from what I overheard Bluewater Bill say, to make us all kings."
"Ah, then I can invent more dirigibles, large ones to carry passengers across the Atlantic," the boys heard Constantio say—though of course, till Ben told them, they were not aware of the speaker's identity.
To their great relief the engine of the dirigible, which had hovered stationary above the galleon during the men's talk, was once more set in motion and the big air-ship drove off at a rapid pace.
"Phew! that was a narrow escape," exclaimed Frank. "I don't want many more like that, I can tell you."
"If they had only gone round the galleon they could not have escaped spying the Golden Eagle," said Harry.
"Fortunate for them they didn't," said Ben grimly, fondling his blue magazine revolver; "they'd have got some indigestible leaden pills, I'm thinking."
"Shooting is just what we want to avoid," said Frank. "I never want to have to fire on a human being."
"Well, if they fire at you first, what are you going to do?" was Ben's incontrovertible argument.
Naturally the Boy Aviators and their companion slept no more that night. The remaining hours before daybreak were occupied with getting everything in first-class shape aboard the Golden Eagle in readiness for what might prove a dash for life.
"Are we faster than the dirigible?" asked Harry, who realized as well as his brother that there might be a chase between the two air-ships.
"I don't know," was Frank's reply, "we ought to be; but from Ben's description, and what we saw of her, that dirigible must be at least a hundred and fifty feet long and she has a more powerful engine than we have."
"But look at her weight," argued Harry.
"That doesn't cut so much figure if you have a powerful enough engine to overcome it," was the reply; "some European dirigibles, bigger than Luther Barr's, have made eighty and even ninety miles."
"Well, we wouldn't stand much chance with an affair like that and that's a fact," commented Harry.
"We can only hope things won't come to such a pass," said Frank.
Soon all was ready for a start and Frank, taking careful bearings, headed the Golden Eagle round on the course she had followed on her way to the galleon. As the sun poked his rim above the horizon the Golden Eagle shot into the air and rapidly the hulls of the galleon and Bluewater Bill's castaway hulk were mere specks behind them.
The spirits of the boys rose. They breakfasted on cold stuff cooked before they started and coffee heated over the exhaust of the engine. Ben lit his pipe, and with Frank at the wheel and Harry on lookout, any one looking at the party in the Golden Eagle would have said that they were a trio of pleasure-makers instead of adventurers engaged on a daring dash for fortune.
It was about nine o'clock in the morning when the danger they had feared loomed up out of the clear sky as suddenly as a tropic squall.
Coming straight toward them, but a mere dot on the sky, though momentarily growing larger, was an air-ship that they could not doubt was Luther Barr's.
"What are you going to do?" asked Harry, as Frank put the wheel over and brought the aeroplane on a course which would take her far to the westward of the dirigible.
"Try to avoid her," was Frank's reply; "they are equipped with a rapid-firing gun and could make mince-meat of us in a short time."
"We have rifles," said Harry.
"They would be little use against such a weapon," replied Frank.
But as the Golden Eagle shifted her course it became clear to those aboard her that the other air-ship did the same.
"They have seen us," gasped Harry.
"Yes, and mean to pursue us, too," was Frank's reply, through gritted teeth; "well, we'll give them a long chase of it."
The Golden Eagle was speeded up to her full capacity, although with the heavy load she was carrying, she by no means attained the speed of which she was capable.
In one thing, however, she had the advantage over the dirigible. She could maneuver with twice the speed and turn and twist like a snake, while the more cumbersome air-ship took a lot of handling to navigate in any intricate movements.
As the dirigible drew nearer, the boys, critical as was the moment, could hardly restrain their admiration at the fine appearance she presented. Her distended gas-bag shone in the sunlight like silk and her cabin woodwork sparkled where brass handholds and plates were attached to it, like the main deck of a passenger liner.
Suddenly, however, her sinister character became apparent.
There was a puff of smoke from what, if she had been a "sea" ship, would have been her bow, and a projectile sang by the Golden Eagle. "That was a warning shot, Frank," cried Ben; "the next will come closer."
"I am going to watch them get ready to fire and then drop suddenly," said Frank, his face white, but with a set, determined look on it.
The man at the lanyard of the dirigible's gun, who looked like Sanborn, bent low over the weapon once more and adjusted it carefully for a second shot, the helmsman of the air-ship at the same time swinging her so that she would be on a direct line with the Golden Eagle.
Frank watched his every movement with a hawk-like intensity. Just as Sanborn stepped back, lanyard in hand, to fire a second shot, Frank dived like a sea-gull sweeping down on a fish and the missile whistled harmlessly overhead.
At the same instant Ben Stubbs, unable to restrain himself any longer, snatched a rifle from one of the lockers and aimed at the pilot-house of Luther Barr's craft.
A shower of splinters flew from the casing of a porthole as his bullet struck, but no further harm was done.
The aeroplane was now far below the dirigible, which was soaring at a height of two thousand feet. At such an angle it was impossible for those on board to use their rapid-fire gun, and Frank, setting the Golden Eagle's rising planes, soared rapidly along at an elevation of about two hundred feet.
By the time the men on the dirigible had got her round, the Golden
Eagle was two miles ahead of the gas-suspended craft.
"We've escaped them," cried Harry.
"Not yet," said Frank; "don't holler till you are out of the woods. They know now we've got the treasure and they are not going to give up the chase as easily as all this."
From time to time the dirigible, which was not gaining on the Golden Eagle, fired a shot from her forward gun, but the dipping, scudding aeroplane afforded a poor mark and, moreover, the deck of a dirigible at full speed is not the steadiest place in the world. So after a few attempts more to wing the swift aeroplane, the crew of the dirigible gave the effort up and turned all their attention to getting every ounce of speed out of their craft. With sinking hearts the boys realized that she was gaining on them.
Hour after hour, above the glassy Sargasso Sea, the battle went on, the aeroplane ducking and diving and gliding and skimming whenever the dirigible got a good chance to send a fatal projectile into her.
From time to time, also, Ben got a chance to send a bullet crashing into the dirigible's gas-bag, and from the actions of the men aboard her they were evidently badly worried by this. However, as Ben knew, the gas-bag of the dirigible was constructed in sections and the gas manufactured by Constantio was so buoyant that if even one section remained intact it would still serve to sustain the dirigible in the air.
But no fight of such a character can endure long. Sooner or later one or the other of the combatants is bound to succumb, and so it was in this case.
Just as Frank was making a dive to avoid, for the twentieth time, getting within range of the dirigible's gun, a skillfully aimed projectile came crashing through the Golden Eagle's gasolene tank. The fluid poured out in a flood.
A few minutes later the engines ceased to revolve and the aeroplane was compelled to descend, Frank driving her down in a long arc that brought her to the surface of the water without accident.
Crippled as she was, the Golden Eagle could not be set going again without repairs that would take hours.
In the meantime their opponents had taken advantage of the aeroplane's plight to riddle her wings with bullets.
Brave as the boys were, they were not foolhardy.
Ten minutes after the fatal accident to the tank, Ben Stubbs, with bitter protests, waved a white shirt in token that the occupants of the Golden Eagle were driven to surrender.