By this time Wat's eyes had become somewhat accustomed to the darkness, and he could make out that the line where the sea met the rocks was brilliantly phosphorescent, and that this pale green glimmer penetrated for some distance into the dark of the rock-cut passage. Wat did not hesitate a moment, but whispering "_For her sake!_" he pushed, with a full breast-stroke, straight into the midst of that sullen, brooding blackness and horror of unsteady water. Outside in the sound he had been conscious of the brisk, changeful grip of winds fretting the water, the swift pull of currents fitful as a woman's lighter fancies, the flash of iridescent silver foam defining and yet concealing the grim cliff edges. But inside there was nothing but the blackness of darkness, made only more apparent by a pervading greenish glimmer which, perhaps because it existed more in the eyes of the swimmer than in the actual illumination of the cavern, revealed nothing tangible, but on the contrary seemed only to render the gloom more tense and horrible. But Wat had made up his mind and was not to be turned aside. He would follow this sea-pass to its end--even if that end should bring death to himself. For at all hazards he was resolved to break a way to his sweetheart, if indeed she yet lived and loved him. The silence of the cave was remarkable. Wat could feel as he swam the slow, regular pulse-beat of the outer ocean-swell which passed up beneath him, and which at each undulation heaved him some way towards the roof. But he could hear no thundering break as it arched itself on the clattering pebbles or broke on the solid rock bottom as it would have done if the cavern had come soon to an end. He oared his way therefore in silence through the midst of the darkness, keeping his place in the centre of the tunnel by instinct, and perhaps also a little by the faint glimmer of phosphorescence which pursued him through the cave. The way seemed endless, but after a while, though the wall of rock continued to stand up on either hand, it grew perceptibly lighter overhead. Wat chanced to look downward between his arms as he swam. A disk of light burned in the pure water beneath him. He turned on his back and glanced up, and there, at the top of an immense black cleft with perpendicular walls, lo! the stars were shining. Without knowing it he had come out of the tunnelled cavern into one of the "goës" or narrow fiords which cut into the Lianacraig fortress of basalt to its very foundations. The passage still kept about the same width, and the water within it heaved and sighed as before, but the rock wall seemed gradually to decrease in height as Wat went on. Also the direction of the "goë" changed every minute, so that Wat had to steer his way carefully in order to avoid striking upon the jutting, half-submerged rocks at the corners.