So the young hero went by land and sea, still westwards, to the very borders of the world, where stands the giant of the west, Atlas, holding up the great vault of the skies on his broad shoulders.  Beyond lay the dreary land of twilight, on the shores of the great ocean that goes round the world, and on the rocks on the shores sat the three old, old nymphs, the Graiæ, who had been born with grey hair, and had but one eye and one tooth among them, which they passed to one another in turn.  When the first had seen the noble-looking youth speeding to them, she handed her eye on, that the next sister might look at him; but Perseus was too quick—he caught the one eye out of her hand, and then told the three poor old nymphs that he did not want to hurt them, but that he must keep their eye till they had told him the way to Medusa the Gorgon.