"Matter enough," was Ben's rejoinder, "he has evidently got that shark line entangled in his clothing and when the monster gave a pull at the hook it yanked him overboard."

"What are we to do?" cried Harry.

"Put on full speed and go about," cried Ben, suiting the action to the word.

At top speed the Bolo rushed through the water after poor Billy, who was still being borne along at a terrific rate by the hooked shark.

"Get ready to shoot the shark when he comes up," yelled Ben.

"But will he come up?" asked Frank.

"He's got to," was Ben's brief reply, "with that hook in him, he's as good as dead. He won't keep under much longer now."

"Hold up, Billy," shouted the boys to their imperiled companion, but the young reporter was too far gone and too choked with the water he had swallowed in trying to keep his head above water to reply.

Frank dived into the cabin and reappeared with a heavy rifle. He slipped into it a cartridge carrying an explosive bullet. Trembling with eagerness, he took up his position on the bow of the speeding Bolo, anxiously scanning the waters ahead for any sign of the shark's reappearance.

Suddenly an ugly black fin loomed up, cutting through the water like the conning tower of a submarine.

"Crack!"

The explosive bullet sped from the rifle, but either Frank's aim was bad from nervousness or the powder charge was too heavy, the ball struck the water fully a foot from the racing creature.

"Try again," said Ben consolingly, "I'll slow down the boat."

Luckily the shark had not dived and his fin still afforded a good mark. It was moving so rapidly, however, that it was going to be a difficult matter to hit the large body that moved beneath it.

Once more Frank rested the rifle and drew a careful sight on the fin.

He aimed a little ahead of it this time, with the result that there was a terrific disturbance of the waters as the bullet sped home and the wounded creature convulsed with the pain.

"Another," cried Ben; "good work."

Before Frank could fit another cartridge--his rifle was a single-chambered one--the shark had dived, leaving only a crimsoned pool on the smooth surface to bear testimony that he was wounded.

The boys uttered a groan of dismay as they saw the thrashing form vanish and a second later saw Billy flash out of view.

It seemed impossible that their chum could survive being dragged to the depths of the sea.

The shark, however, did not remain down long. It soon reappeared on the surface, with Billy in tow, still thrashing the water into crimson fountains with its fins and tail. Sometimes it leaped clear out of the water in its agony.

"Bang!"

Another bullet sped from Frank's rifle, and this time the maddened animal seemed to sense from whence came the attack, for it suddenly charged furiously at the motor-boat.

Quick as thought, Ben Stubbs, who had seen its coming, leaned over the side and with his seaman's knife in hand waited the moment when it dived under the boat.

As it did so he gave a quick downward slash.

The rope that seemed to be pulling Billy to his doom severed under the blade with a crack. The next minute the young reporter was able to swim feebly to the side of the Bolo.

Badly weakened and unnerved by his experience he was pulled on board and laid on a bunk in the cabin, where restoratives were administered to him.

It was late in the evening before he was himself again, and he then explained how he had been idly twisting the line in and out of a hook on his belt when there came a sudden tug. Before he knew what was happening he found himself rushing through the air and was then immersed. Fortunately, he was a good swimmer and kept his head or there might have been a more serious termination to his adventure.

"How big do you think that shark was, Billy Barnes?" Frank could not help asking him mischievously later in the evening.

"Oh, at least fifty feet," was the young reporter's reply, delivered in all seriousness.

CHAPTER XVIII.

INTO THE SARGa.s.sO.

The days slipped rapidly by until one fine morning, about a week after the events narrated in our last chapter, Ben Stubbs and Frank announced that their observations showed that they had doubled the southernmost cape of Florida (which had been the scene of some earlier thrilling adventures described in the second volume of this series, "The Boy Aviators on Secret Service"), and were now on a direct course for the mysterious region of the Sarga.s.so Sea. For three days more they went steadily onward toward the rising sun, occasionally sighting a school of porpoises and scaring up whole legions of flying-fish with their sharp bow. The days were glorious--a trifle hot, perhaps, but none of the boys minded that; and at night the stars, "as big as lamps," Billy declared they looked in the far southern lat.i.tude they had now reached, gave almost as much light as the moon in our chilly northern clime.

Every day, now, some one of the party took turns with the gla.s.ses under a small shelter erected with canvas and oars in the bow of the boat, and painstakingly scanned the horizon all about for any sight of the Brigand or Luther Barr's dirigible. But although once or twice they saw distant smoke, it always turned out to be a false alarm, and they hourly grew nearer the Sarga.s.so without having made out a trace of the rival treasure-hunters. This fact put them all in high spirits, and each of the boys was already busy building lofty air-castles concerning what he would do with the treasure when he got it.

Much of the time, too, was occupied in clearing away the lashings of the planes and other apparatus and parts of the Golden Eagle attached to the cabin top forward, and discussing plans to erect her at sea.

Frank perhaps was the only one of the party who fully realized the extreme difficulties that confronted them. However, the water was at present smooth as gla.s.s almost and seemed likely to remain so, if Bluewater Bill and Ben Stubbs were to be relied on as weather prophets.

"We are getting into the Doldrums now for fair," the old sailor announced one morning, pointing to the horizon, where a big, full-rigged vessel lay motionless in the breathless atmosphere. "That ship yonder may not get out of here for a week."

The chart now showed that they were far out of the track of all ships and on a lonely sea, so that the becalmed wind-jammer had probably been driven off her course in the same hurricane that menaced them and was likely to be a long time before she got out of her melancholy predicament.

One day Billy, who was leaning over the side, gave a sharp cry and drew back from the bulwarks.

"Come here, fellows--ugh, what an awful-looking thing," he cried.

He pointed down at the sea. The others rushed to his side, and as they gazed into the water, which was as clear as crystal for a considerable depth, they felt like echoing his exclamation of repulsion.

Through the opalescent green overside could be seen a huge shadowy shape slowly settling downward, though from the depth two menacing eyes gleamed upward at the young watchers.

From every side of the creature's round, barrel-like body stretched huge arms covered with myriads of suckers. It looked like some evil spirit of the deep, and the boys estimated the length of its arms as at least twenty-five feet. It slowly waved the long feelers as if in farewell as it sank.

"That there's a devil-fish," proclaimed Ben, who had joined the group as the monster vanished, "some calls 'em octopus, but devil-fish is a better word, to my thinking."

The boys agreed with him.

"Surely that must have been an unusually large one, Ben?" exclaimed Frank, still with the feeling of repulsion with which the monster had imbued him strong upon him.

"A big one," echoed Ben. "Oh, no, not so extra big--though he was sizeable, I'll admit. I've never seen such things myself, but I've heard crews of whalers tell of having been attacked by one of them critters, and sometimes they come back to the ship several men short.

Them devil-fish are as ferocious as tigers and many's the poor sponge-diver they have gobbled up."

"Are there any in Sarga.s.so Sea?" asked Billy, who seemed fascinated by the subject.

"I should say there are," put in Bluewater Bill, "and they grow there as big as elephants to a rabbit compared to this fellow. I don't doubt that some of them has lived there for hundreds of years, just like turtles. You see it's a fine place for feeding in, among all that seaweed, and when a ship gets in there and some poor chap goes crazy and jumps overboard, why, then they have an extra nice morsel to make 'em get fat and live long."