As they went Jack flashed a swift word to Ned.

“You say that the chests my father took such care of are still in the cabin?”

“Yes; in the Professor’s stateroom.”

“Good. I’ve a notion they contain something that may prove valuable to us right now. Open them up and see if one of them contains some queer-looking guns. If it does, bring the weapons on deck right away, and—summon Captain Andrews.”

Ned retraced his steps and Jack ran swiftly up after Tom. On deck they found the sailors running about distractedly. The shot they had heard had carried away part of the foremast of the Sea King. The wreckage lay in a tangle, about which the seamen hovered confusedly.

While the boys still stood regarding the scene, hardly knowing for the moment what to do, a stoutly-built man, with an overcoat hastily thrown on over a suit of pajamas, joined them. It was Captain Andrews. The light from the incandescents fell on his bronzed, blonde-bearded face, and Jack felt, as he clasped the newcomer’s hand, that here was a man who could be relied on to the last ditch.

“Ned Bangs told me I would find you here,” he said. “I hastened on deck right away. I should have been out and about long ago; but——”

“That’s all right, captain,” spoke Jack swiftly, “you had earned your rest and no mistake. The thing is, what are we going to do now?”

“The rascal Herrera has attacked us, Ned told me.”

“Yes. His craft is in the offing now. He has shot away part of the foremast. The riding-light on it must have acted as a target for him.”

As the lad spoke a voice came cut of the darkness:

“We want that silver casket. Are you going to give it up peaceably, or do we have to blow your vessel out of the water?”

“You infernal scoundrels!” shouted Andrews, before Jack could check him.

The captain bounded forward to a machine gun. With quick, nervous fingers he was ripping off its cover when Jack laid a hand on his arm.

“Hold on a minute, captain,” he said, “I’ve another plan. We shall know in a few seconds now if it will succeed.”

The captain looked at him wonderingly.

“They outnumber and outarm us,” he began. But Jack broke in:

“I’ve an idea that one of those chests in my father’s cabin contains some novel weapons,” he said, “a new kind of gun, the invention of Tom and myself. They contain a magazine of shells loaded with a gas which will paralyze any form of animal life with which they come in contact.”

The captain gasped.

“Well,” he said, “I’d heard that you kids were inventive wonders, but this——”

“Oh, we didn’t invent the gas,” interposed Tom, who had been an interested listener to Jack’s last words, “Professor Chadwick did that. But we applied it to use in the guns.”

“And they work?”

“Well, we’ve tried them on rabbits and small game, and brought down whatever we aimed at. You see, the shells are loaded with this gas in a semi-solid form. When the gun is fired a fuse is lighted, which releases the gases, and they fill the atmosphere, surrounding anything they strike with a vapor that causes temporary helplessness.”

As Jack spoke there came another hail out of the darkness.

“We are waiting. Resistance is useless. We know you have that casket with you. What is your answer?”

“Will you give us a few moments to consider?” shouted back Jack.

A pause followed.

“I wonder how on earth they know that Ned and the rest secured the casket?” wondered Tom.

This was a poser. It was not till long afterward that they found out that, following the discovery of their escape from the Tarantula, a sailor had noticed the severed string hanging from the porthole of the Professor’s cabin prison. Herrera’s keen mind at once guessed the purpose it had served, and also surmised that the casket must be very valuable. Professor Chadwick, on being questioned, admitted,—thinking of course that the Sea King was by that time out of danger of pursuit,—the manner in which he had tricked the Mexican and the contents of the box.

Suddenly, out of the darkness, ranged the ghostly outlines of El Tarantula. Hardly twenty-five yards separated her from the Sea King. She was moving slowly, far below her usual swift motion. Her dash from the mainland had resulted in overheated engines, which accounted for the space of time those on board the Sea King had been free from her presence.

“We’ll give you five minutes and no more,” came a voice from her midships.

“Good,” murmured Jack, as he heard the terms of the armistice, “that ought to be plenty of time and—Oh, glory be!”

Ned had come on deck while the young leader was speaking. In his arms he carried a collection of as strange-looking weapons as were ever seen outside of a museum. Yet they represented a type of gun destined to become famous.

“Hurray!” muttered Tom under his breath, “they’re the gas-guns, sure enough.”

While Captain Andrews’ eyes fairly bulged. Jack took one of the guns. They were of a dull colored metal, allowing no light to glint from any bright surfaces. A barrel about three and a half feet in length, terminated in a cylinder of greater diameter than the barrel itself. This was a muffler, which effectually silenced the sound of the spring that was used to send the gas globes on their way and snap the fuses. The stocks of these odd firearms, if such they could be called, were large, and contained sixteen “gas globes”—spheres of a tough and glutinous kind of gelatine, filled with the destructive gas—a compound of ammonium nitrate,—in a semi-liquid form.

“How do you fire them?” asked Captain Andrews.

“Handle them just as you would an ordinary gun,” rejoined Jack. “The globes will burst when they strike the Tarantula and spread the gas they contain broadcast. Luckily, the craft is to leeward of us, or we might be in danger of getting a dose of our own medicine when the gas globes detonate.”

“Will the gas kill them?” asked Captain Andrews, in such a vindictive tone that Jack couldn’t help smiling.

“Hardly,” he said; “but it will take the fight out of them for a while, I imagine.”

Acting under the lad’s instructions. Captain Andrews summoned some of the interested sailors to him. There were twelve of the guns “and a chest full of ammunition below,” whispered Ned.

Eight of the men were given a gas-gun each. Their faces expanded in grins as they learned the nature of the novel weapons.

“First time I ever heard of knocking a feller out with a gas pill,” said one of them in an undertone.

The serving out of the gas-guns had hardly been completed when the voice from the Tarantula hailed them again:

“Five minutes is up,” it said; “we’re going to board you.”

At the same instant the Tarantula began to range in alongside. Evidently those on board her did not fear resistance, for as she drew closer her decks blazed with light, and those on board the Sea King could see that her machine guns were trained full on the yacht.

Under Jack’s orders the armed portion of the Sea King’s company had dropped behind the bulwarks, aiming their guns through scupper holes. Thus, of course, all that was revealed to the enemy was a group of flurried-looking sailors standing about the wreckage of the mast forward. Hardly ten yards separated the two vessels when Jack gave the whispered command: “Fire!”

What followed, so Tom described it afterward to the author, “was like watching a moving picture.”

There was no sound as the triggers on the gas-guns were pulled, but as the collapsible globes struck the Tarantula’s decks and superstructure and burst with a soft, pattering sound, her crew began to roll about like drunken men.

As the stupefying vapors impregnated the air with their fumes, one after another the men began to drop like flies. The resistance of the stoutest didn’t endure for more than a space of five minutes. Herrera himself, the last to succumb, fell beside the wheel house as he was shouting at the helmsman to withdraw from the infected air.

The young inventors’ wonderful gas-guns had received their first real test, and had surely not been found wanting in efficiency. The Tarantula, a few moments since the scene of feverish activity, now lay a drifting hulk. Her engines were still slowly revolving, but there was no hand to govern them. Several of the gas globes had been aimed at the engine-room hatches, which were open. Deflecting thence they had burst into the machinery space, stupefying the force at work there.

The victory was complete and sweeping.