The weather had by this time reverted to quite its normal condition; the trade-wind was blowing steadily, the sea had gone down, and I had nothing worse than a somewhat heavy swell to contend with; I therefore felt that, unless I should be so unfortunate as to fall in with another gale, there was no reason at all why I should not reach my destination safely, and without very much discomfort.  My only trouble was that, running, as the boat now was, with the wind so far over the starboard quarter, I dared not release my hold upon the tiller for an instant, lest she should broach-to and, possibly, capsize.  Whenever, therefore, it became necessary for me to quit the helm for the purpose of taking an astronomical observation, or otherwise, I had to heave-to, and, occasionally, to shorten sail while doing so, which kept me pretty actively employed, off and on, all day.  Thus, about nine o'clock in the morning, I had to heave-to and leave the boat to take care of herself while I secured observations of the sun for the determination of the longitude; the same procedure had to be adopted again at noon when I took the sun's altitude for the determination of the latitude; and the preparation of a meal involved a further repetition of the manoeuvre. Thus I had no time to feel lonely, at least during the hours of daylight; but after nightfall, surrounded and hemmed in by the gloom and mystery of the darkness, with no companionship save that of the multitudinous stars--which, to my mind, never betray their immeasurable distance so clearly as when one is in mid-ocean--with the sough and moan of the night wind and the soft, seething hiss of the sea whispering in one's ears, the feeling of loneliness becomes almost an obsession, the sense of all-pervading mystery persistently obtrudes itself, and one quickly falls into a condition of readiness to believe the most incredible of the countless weird stories that sailors love to relate to each other, especially when this condition of credulity is helped, as it sometimes is, by the sudden irruption of some strange, unaccountable sound, or succession of sounds, upon the peaceful quietude and serenity of the night.  These sounds are occasionally of the weirdest and most hair-raising quality; and while the startled listener may possibly have heard it asserted, time and again, by superior persons, that they emanate from sea birds, or from fish, he is perfectly satisfied that neither sea birds nor fish have ever been known to emit such sounds _in the daytime_, and the strain of superstition within him awakes and whispers all sorts of uncanny suggestions, the sea bird and fish theory being rejected with scorn.  Moreover, those harrowingly mysterious sounds seem never to make themselves audible save when the accompanying circumstances are such as to conduce to the most startling and thrilling effect; thus, although I had now been knocking about at sea for more than three years, and had met with many queer experiences, I had never, thus far, heard a sound that I could not reasonably account for and attribute to some known source; yet on this particular night--my second night alone in the longboat--I was sitting comfortably enough in the stern-sheets, steering by a star--for I had no lantern wherewith to illuminate my compass--and thinking of nothing in particular, when suddenly a most unearthly cry came pealing out of the darkness on the starboard beam, seemingly not half a dozen yards away, and was twice repeated.