"What!" cried the captain. "Sail ho!" shouted the man at the look-out, and in a moment all was excitement, for, about a mile away, down what looked like a clear lane through the white fog, was a two-masted vessel, crowded with sail; and as rapidly as possible the boats were hoisted up, and the _Nautilus_ was in pursuit. But hardly had she careened over under the press of sail than the fog shut the vessel from their sight, and for the next two hours she was invisible, while the captain of the _Nautilus_ had to lie to, for fear of some slippery trick on the part of what was undoubtedly the slaver, since she was more likely to make for the shelter of a creek than to risk safety in flight. But the wind was not favourable for this manoeuvre, and toward mid-day the sea grew clear, and there was the slaver plainly visible miles away, sailing out west, while the _Nautilus_ crowded on every stitch of canvas in pursuit. A stern chase is a long one, says the proverb, and night came with the craft still miles away, but the sky was brilliantly clear, and the moon shone forth, showing the white-sailed schooner in a strangely weird fashion far across the flashing sea. "We're gaining on her," said Bob Howlett, who was as full of excitement as the men, while Mark felt a strange suffocating sensation at the chest as he strained his eyes and watched the swift schooner, whose captain tried every manoeuvre to escape the dogged pursuit of the Queen's cruiser. "Hang it all! he's a plucky one," said Bob, as the chase went on. "He must be taken, but he won't own to it." "Thought a ship was a she," said Mark. "Well, I was talking about the skipper, wasn't I?" "A man doesn't want to lose his ship, of course." "Nor his cargo," cried Bob. "There, give it up, old fellow; we're overhauling you fast." It was a fact: the _Nautilus_, with all her studding sails set, was creeping nearer and nearer, till at last, amid no little excitement on the part of the two midshipmen, a gun was shotted, run out, and a turn or two given to the wheel. Then, as the _Nautilus_ swerved a little from her course, the word was given, and a shot went skipping across the moonlit sea, splashing up the water in a thousand scintillations, and taking its final plunge far ahead of the schooner. Every eye and every glass was fixed upon the slaver, for such she was without a doubt, since she kept on, paying no heed to the shot and its summons to heave to; and after a second had been sent in chase, the captain gave the word, and a steady fire was kept up at the spars and rigging. "I can't fire at her hull, Staples," the captain said. "No, it would be slaughtering the poor wretches down below; never mind, sir, we'll capture her directly. She's ours, safe." "Then the sooner the better," said Bob to his companion.