Caius understood that he had still three miles of the level beach to tread. At first he hardly felt the sand under his feet, they were so dead with cold. The spray from the roaring tide struck his face sideways. He had time now to watch each variation, each in and out of the dune, and he looked at them eagerly, as the only change that was afforded to the monotony. Then for the first time he learned how completely a man is shut out from all one half of the world by the simple command not to look behind him, and all the unseen half of his world became rife, in his thought, with mysterious creatures and their works. At first he felt that he was courting certain death by keeping the word he had given; in the clap of the waves he seemed to hear the pistol-shot that was to be his doom, or the knife-like breath of the wind seemed the dagger in the hand of a following murderer. But as he went on and no evil fate befell, his fear died, and only curiosity remained—a curiosity so lively that it fixed eagerly upon the stretch of the surf behind him, upon his own footsteps left on the soft sand, upon the sand-hills that he had passed, although they were almost the same as the sand-hills that were before. It would have been a positive joy to him to turn and look at any of these things. While his mind dwelt upon it, he almost grudged each advancing step, because it put more of the interesting world into the region from which he was shut out as wholly as if a wall of separation sprang up between the behind and before.

By an effort of will he turned his thought from this desire, or from considering what the mysterious something could be that it was all-important for him not to see, or who it was that in this desolate place would spy upon him if he broke his vow.

When his activity had set the blood again coursing warmly in his veins, all that was paltry and depressing passed from his mind and heart, as a mist is rolled away by the wind. The sweet, wild air, that in those regions is an elixir of life to the stranger, making him young if he be old, and if he be young making him feel as demigods felt in days of yore, for a day and a night had been doing its work upon him. Mere life and motion became to him a delight such as he had never felt before; and when the moon came out again from the other side of the cloud, the sight of her beams upon surf and sand was like a rare wild joy. He was glad that no one interfered with his pleasure, that he was, as far as he knew, alone with the clouds that were winging their way among moonbeams in the violet sky, and with the waves and the wind with which he held companionship.

He had gone a mile, it might be more; he heard a step behind him. In vain he tried to convince himself that some noise natural to the lonely beach deceived him. In the high tide of life that the bracing air had brought him, his senses were acute and true. He knew that he heard this step: it was light, like a child's; it was nimble, like a fawn's; sometimes it was very near him. He was not in the least afraid; but do what he would, his mind could form no idea of what creature it might be who thus attended him. No dark or fearful picture crossed his mind just then; all its images were good.

The fleet of white clouds that were sailing in the sky rang glad changes upon the beauty of the moonlit scene. Half a mile or more Caius walked listening to the footstep; then he came on a wrecked boat buried in the sand, its rim laid bare by the tide. Caius struck his foot and fell upon it.

Striking his head, stunned for a moment, then springing up again, in the motion of falling or rising, he knew not how, he saw the beach behind him—the waves that were now nearing the foot of the dune, the track between with his footsteps upon it, and, standing in this track, alert to fly if need be, the figure of a girl. Her dress was all blown by the wind, her curling hair was like a twining garland round her face, and her face—ah! that face: he knew it as well as, far better than he knew his own; its oval curves, its dimpled sweetness, its laughing eyes. Just for such brief seconds of time as were necessary for perfect recognition he saw it; and then, impelled by his former purpose—no time now for a new volition—he got himself up and walked on, with his eyes in front as before.

He thought the sea-maid did not know that he had seen her, for her footsteps came on after his own. Or, if she knew, she trusted him not to turn. That was well; she might trust him. Never in his life had Caius felt less temptation to do the thing that he held to be false. He knew now, for he had seen the whole line of the beach, that there was nothing there for him to fear, nothing that could give any adequate reason to any man to compel him to walk as he now walked. That did not matter; he had given his word. In the physical exaltation of the hour the best of him was uppermost. Like the angels, who walk in heavenly paths, he had no desire to be a thing that could stoop from moral rectitude. The knowledge that his old love of the sea was his companion only enhanced the strength of his vow, only made all that the strength of vows mean more dear to him; and the moonlit shore was more beautiful, and life, each moment that he was then living, more absolutely good.

So they went on, and he did not try to think where the sea-maid had come from, or whether the gray flapping dress and the girlish step were but the phantom guise that she could don for the hour, or whether, if he should turn and pursue her, she would drop from her upright height into the scaly folds that he had once seen, and plunge into the waves, or whether that had been the masquerade, and she a true woman of the land. He did not know or care. Come what come might, his spirit walked the beach that night with the beautiful spirit that the face of the sea-maid interpreted to him.