Once the headland was passed and the sheer precipitous westward cliffs loomed black out of the sea, he became more and more uneasy. As yet, there was no danger; but he saw that a swell was moving out of the west; and whenever the wind blew that way, the sea-arcades were filled with a lifting, perilous wave. Later, escape might be difficult, and often impossible. Out of the score or more great passages which opened between Aoidhu and Ardgorm, it was difficult to know into which to chance the search of Alan. Together they had examined all of them. Some twisted but slightly; others wound sinuously till the green, serpentine alleys, flanked by basalt walls hundreds of feet high, lost themselves in an indistinguishable maze. But that which was safest, and wherein a boat could most easily make its way against wind or tide, was the huge, cavernous passage known locally as the Uaimh-nan-roin, the Cave of the Seals. For this opening Ian steered his boat. Soon he was within the wide corridor. Like the great cave at Staffa, it was wrought as an aisle in some natural cathedral; the rocks, too, were columnar, and rose in flawless symmetry, as though graven by the hand of man. At the far end of this gigantic aisle, there diverges a long, narrow arcade, filled by day with the green shine of the water, and by night, when the moon is up, with a pale froth of light. It is one of the few where there are open gateways for the sea and the wandering light, and by its spherical shape almost the only safe passage in a season of heavy wind. Half-way along this arched arcade a corridor leads to a round cup-like cavern, midway in which stands a huge mass of black basalt, in shape suggestive of a titanic altar. Thus it must have impressed the imagination of the islanders of old; for by them, even in a remote day, it was called Teampull-Mara, the Temple of the Sea. Owing to the narrowness of the passage, and to the smooth, unbroken walls which rise sheer from the green depths into an invisible darkness, the Strait of the Temple is not one wherein to linger long, save in a time of calm. Instinctively, however, Ian quietly headed his boat along this narrow way. When, silently, he emerged from the arcade, he could just discern the mass of basalt at the far end of the cavern. But there, seated in his boat, was Alan, apparently idly adrift, for one oar floated in the water alongside, and the other swung listlessly from the tholes. His heart had a suffocating grip as he saw him whom he had come to seek. Why that absolute stillness, that strange, listless indifference? For a dreadful moment he feared death had indeed come to him in that lonely place where, as an ancient legend had it, a woman of old time had perished, and ever since had wrought death upon any who came thither solitary and unhappy.