For these vigias, the terror of seamen, are like malicious spirits. Some man has seen them, or has imagined them, and for ever after they bear sway in the minds of those who sail upon the great deep. Perhaps they are but a floating mass of wreck, on which the sea breaks; in the south, what was seen was, it may be, a drifting berg; on the shores of West Africa, perchance a river has sent out a floating island. Any accident of imagination may create them; alcohol bears them on its tide: they are the rats and ghosts and terrible creeping things of the delirium of the sea that is born of rum. A heavy heeled spar as it floats becomes a pinnacle of rock; the boat that bears dead men in it is for ever after to be avoided. Here a rip of currents, and there a heavy overfall, become fixed terrors and are given names. For this is the sea that is unknown yet, and shall for ever be unknown. It works upon the mind of man very subtly, and yet again with tremendous strength. Under the sea are earthquakes, and in it volcanoes. Of these islands are born, and again they pass away, while the little creature man skims upon the surface of the ocean like a water-beetle, and may be seen no more. When Green was left alone upon the poop of the _Palembang_, save for the presence of the man at the wheel, something of the wonderful majesty of the sea came down upon him, and for a moment touched his nerves. Trust in the captain he had none, for Spiller was of the usual alcoholic order; so he got out the chart and looked at it. There stood the vigia marked "Simoom Rock." Perhaps it existed after all. He remembered the history of the Aurora Islands to the cast of the Falklands. Even now, some old sailors believe there are such islands, real land, not ice grounded on deep soundings. And the Simoom vigia was close at hand, if it existed at all. Allowing for sufficient uncertainty in its supposed position, it might be anywhere within a degree. He stared out into the darkness and imagined he saw it. It was here, it was there, it was nowhere: it was a wraith of the mind, and dissolved. He put back his night-glasses, and whistled, till he remembered there was quite enough wind, and that he had no desire to turn the hands up to shorten sail.