Nobody dawdled very long over breakfast that morning; for, in the first place, the heat below was simply unbearable, and, in the next, we were all far too anxious to allow of our remaining in our berths while we knew that every conceivable expedient would be adopted by the captain to shorten the distance between us and the chase.  It was my watch below from eight o'clock until noon, and I was consequently off duty; but although I had been on deck for eight hours of the twelve during the preceding night, I was much too fidgety to turn in and endeavour to get a little sleep; I therefore routed out a small pocket sextant that had been presented to me by a friend, and, making my way up into the fore- topmast cross-trees--from which the strangers could be seen--I very carefully measured with the instrument the angle subtended by the mast- head of the brig and the horizon, so that I might be able to ascertain from time to time whether or not that craft was increasing the distance between her and ourselves.  I decided to measure this angle every half- hour; and, having made my first and second observations without discovering any appreciable difference between them, I employed the interval in looking about me, and watching the movements of two large sharks which were dodging off and on close alongside the ship, and which were clearly visible from my post of observation.  At length, as "three bells"--half-past nine-o'clock--struck, I cast a glance all round the ship before again measuring my angle, when, away down in the south- eastern quarter, I caught a glimpse of very pale blue stretching along the horizon that elsewhere was indistinguishable owing to the glassy calm of the ocean's surface.