"All right, we'll see," replied Mr Marline, using his stock phrase, and the two continued to walk up and down chatting about other matters, while I went and sat down close to the taffrail, looking out over the sea and wondering what the moaning sound of the ocean meant. I let my imagination wander over the old stories I had heard of the mermaids below, and how they sang their weird songs of lament whenever a storm was coming, anticipating the shipwrecks that would follow and the invasion of their coral caves by the bodies of drowned mortals, over whom they are said to weep tears of pearl; and, in the flickering light of the stars, that seemed to come from underneath the purple deep and not be shining down from above, I almost fancied I could distinguish the sirens looking up at me from below the water with sad faces, as they combed their long weed-like tresses and raised their wailing croon. Presently, however, I observed the star reflections suddenly disappear from view; and then, the water grew greyer and greyer, until I was hardly able to see it at all under the stern of the vessel, a hazy obscurity enveloping all below and around. I roused myself with a start, thinking this effect was produced by the gloom of night, and that I had fallen asleep while weaving my quaint fancies anent the mermaidens; but a couple of sharp strokes of the ship's bell sounding through the still air at that moment told me it was only nine o'clock. I then recognised the fact that I must seek some other reason for the sombre tone of the sea, as I knew well enough that the little beacons in the sky that had before lit it up, were not in the habit of drawing on their hatches until it was pretty nearly time for the sun to set about getting up for his day's work, unless something out of the common was going to happen. Looking up, therefore, I was surprised to see a dense black cloud now covering over the heavens like a pall. It must have crept up from somewhere almost instantaneously; for, twenty minutes before, the sky was clear and bright, while now it was totally obscured from the horizon to the zenith, the angel of darkness seeming to be treading over the face of the deep. Just then, away ahead on the starboard bow to the eastwards, a window appeared to be opened for an instant in the dense veil, from which a vivid flash of lightning came forth, making the darkness even more visible as the cloud closed up again. "Shall I go and hail Captain Miles now, sir?" I heard Jackson ask Mr Marline near me, although I could not clearly make out either of them in the thick gloom--indeed, I could not see to the other side of the deck, or perceive the mizzen-mast even. "No, I hardly think there's any need yet," I distinguished Mr Marline's voice say in reply. "It's only a flash of lightning--nothing to make a fuss about, for there isn't a breath of wind stirring yet." "It's coming though," the other rejoined. "I can smell it."