Again Chayne's face was turned quickly toward her. Here indeed was a sign of the people amongst whom she lived, and of their unillumined thoughts. There must be the personal reason always, the personal reason or money. Outside of these, there were no motives. He answered her gently: "No; I think that was not the reason. How shall I put it to you?" He leaned forward with his elbows upon his knees, and spoke slowly, choosing his words. "I think these guides obeyed a law, a law not of any man's making, and the one law last broken--the law that what you know, that you must do, if by doing it you can save a life. I should think nine medals out of ten given by the Humane Society are given because of the compulsion of that law. If you can swim, sail a boat, or climb a mountain, and the moment comes when a life can only be saved if you use your knowledge--well, you have got to use it. That's the law. Very often, I have no doubt, it's quite reluctantly obeyed, in most cases I think it's obeyed by instinct, without consideration of the consequences. But it _is_ obeyed, and the guides obeyed it when so many of them came with me on to the Glacier des Nantillons." He heard the girl at his side draw in a sharp breath. She shivered. "You are cold?" "No," she answered. "But that, too, is all strange to me. I should have known of that law without the need to be told of it. But I shall not forget it." Again humility was very audible in the quiet tone of her voice. She understood that she had been instructed. She felt she should not have needed it. She faced her ignorance frankly. "What one knows, that one must do," she repeated, fixing the words in her mind, "if by doing it one can save a life. No, I shall not forget that." She rose from the seat. "I must go in." "Yes," cried Chayne, starting up. "You have stayed up too long as it is. You will be tired to-morrow." "Not till to-morrow evening," she said, with a laugh. She looked upward to the starlit sky. "It will be fine, I hope. Oh, it _must_ be fine. To-morrow is my one day. I do so want it to be perfect," she exclaimed. "I don't think you need fear." She held out her hand to him. "This is good-by, I suppose," she said, and she did not hide the regret the words brought to her. Chayne took her hand and kept it for a second or two. He ought to start an hour and a half before her. That he knew very well. But he answered: "No. We go the same road for a little while. When do you start?" "At half past one." "I too. It will be daybreak before we say good-by. I wonder whether you will sleep at all to-night. I never do the first night." He spoke lightly, and she answered him in the same key. "I shall hardly know whether I sleep or wake, with the noise of that stream rising through my window. For so far back as I can remember I always dream of running water."