“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.