Presently the coast-line sinks to a more moderate height. The tower of Damecuta is seen ahead, and below it a stair, cut in the face of the rock, leads down to a low arched opening, through which the blue sea is washing in and out. A couple of women in gay dresses are sitting in the shade upon the stair. A few boats are rocking on the blue water, strangely, intensely blue, even in the morning shadow which the cliffs fling out across the sea. It was not the rich, royal colour which one may see about the shores of western England, nor yet the exquisite soft turquoise which glows by all the bays and headlands of this coast, but a darker and more watery blue, verging on indigo rather than on any other single colour. The boat approached the opening. The boatman, warning me to lie flat in the stern, shipped his oars, grasped a chain which was fastened to the rock, and, at the lowest point of the wet, winding entrance, flung himself backward on my body, while the boat shot into what for an instant seemed a moonlit darkness. But on struggling up erect I became conscious of a strange, milky radiance, which grew and brightened as the sight adjusted itself, until I saw that the waves washing round the boat were of a silvery blue, which is like nothing else, lambent, incandescent, flashing with the softest glow imaginable. One thinks of the shimmering flashes in the heart of an opal, of the flame of phosphorus, of the most delicate colour on a blue bird's throat--there is no similitude for that which has no match, nothing else upon the earth which is not gross when set beside these waves of purest light, impalpable, unsubstantial, and radiantly clear. "Che colore?" I asked in wonder; and the boatman, no less awed by the strange beauty, answered very low, "Il cielo," and sat silent, stirring his oar gently, so as to make spouts of light among the blue reflections. The roof of the Blue Grotto, low-spreading near the entrance, rises at the centre into a domed vault. It is not dark--nowhere in the grotto is it dark--it is neither light nor dark, but blue; blue pervades the air, and plays about the crannies of the roof like flame, far paler than the sea, yet quick and living.