"One question I should like to ask--I hope you will not think me impertinent or unduly inquisitive--that is, where did you obtain your officers?" The captain pursed his lips for a few moments before replying. "They are, for the most part, gentlemen," he observed. "But, unfortunately, they have fallen in the social scale, and wish to regard their past as a closed book. I can tell you of a few cases, though, of course, in strict confidence. Mr. Palmer, one of our lieutenants, for example, was but a few years ago a commander in the Royal Navy. Ran his vessel full tilt on the rocks, was court-martialled, and 'smashed.' As far as his friends are concerned, Palmer--though that is not his real name--is supposed to be away for a three-years' tour in the Rockies. Then there's White, the surgeon--also an _alias_, by the bye. He was a well-known country doctor with a good practice till he fell foul of a coroner's court over some trivial detail. It broke him as far as England was concerned." "And the men?" "Are mostly the discarded victims of the British Admiralty's short service system, with a sprinkling of merchant seamen who have been ousted by cheap and inferior foreigners." "Are you not afraid that some of them will desert and reveal the secret of the _Olive Branch_?" "It matters little so long as they do not desert in a body; but, thanks to the condition under which they are engaged, I do not anticipate any trouble in that direction. No man is acquainted with the whole of this vessel's mechanism. Even the officers' duties are not entirely interchangeable. For instance, Sinclair, the gunnery Jack, would be helpless on the Z-rays; Taylor--oh! I have forgotten something, after all. With the load of responsibility on my shoulders it's a wonder that I am not even more forgetful. There's Taylor, the scientist; he runs the laboratory with Guy Temple as his assistant. I have not yet shown you his sanctum." The laboratory was a spacious apartment on the starboard side of the base of the fore-turret, with a hatchway communicating with the orlop deck. In one corner was a wide bench covered with test tubes, retorts, and similar articles used in chemistry, while on the floor were ranged nearly a hundred cylinders. "Where's Mr. Taylor?" asked Captain Brookes, of an alert young officer who was engaged in some experiment of scientific research. "I have not seen him during the last two hours, sir." "H'm!" "Shall I send for him, sir?" "No, it does not matter particularly. Now, Mr. Tregarthen. Here are the explosive charges for the 6in. shells. The projectiles are discharged with Whaddite, an improved form of cordite, but what do you think is the composition of the bursting charges? I'll tell you; it's liquid air. With this explosive a 6in. is more deadly than a thirteen point five shell charged with lyddite. No armour plate can withstand it. Directly we have parted company with the tramp we have in tow, I'll give a demonstration of its power."