“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.”