"No," I agreed; "you're right there. Myra must be kept in the dark." "Yes," he replied, with a look of relief. "It might have a serious effect on her chances of recovery if she had this additional worry. And I don't think it would be advisable to tell the old man either. I think we had better keep it to ourselves absolutely. Tell no one, Ewart, except your friend when he comes." "Very well," I answered, for I was very anxious to spare both Myra and her father from the knowledge of any further trouble. "I'll tell Dennis when he comes, but otherwise it is our secret." "Good," said Garnesk. "Now put your coat on, old chap, and we'll stroll back to the house." I got up and buttoned my collar, retied my bow, and slipped into my jacket. I was rather uncomfortably damp, and I felt a bit shaky and queer, and decided that I could do with a complete rest from the mysteries of the green ray. But the subject remained uppermost in my mind, and my tired brain still strove to unravel the tangled threads of the puzzle. "By the way," I said, as we walked slowly up to the house, "you have not yet explained what there was in my remark about the sunlight that made you think of the yacht." "Well," he replied, "you see I had an idea that perhaps they might come here when the gorge, through which the river flows, was flooded with light, so that they could see if any strange effects were produced. But that suffocation was not brought about by any electrical experiment, and I am beginning to be afraid that, after all, we may be up against some strange natural phenomena, some terrible combination of the forces of Nature, which has not yet been observed, or at any rate recorded." "Why afraid?" I asked, for although I had been glad to believe that we were faced with a problem which would prove to have a human solution, the revulsion had come, and I should have welcomed the knowledge that some weird, freakish application of natural power might be held accountable. "Afraid?" queried Garnesk, with a note of surprise. "I am very often afraid of Nature. She is a devoted slave, but a cruel mistress. I don't think that I should ever be very much scared by a human being, even in his most fiendish aspect, but Nature--I tell you, Ewart, there are things in Nature that make me shudder!" "Yes," I agreed heavily, "you're right, of course. That's how I have felt for the past twenty-four hours. It was a tremendous relief to me to feel that we were men looking for men. But the last few minutes I have had an idea that it would be comforting to explain it all out of a text-book of physics. Still, you're right. It is better far to be men fighting men than to be puny molecules tossed in the maelstrom of immutable power which created the world, and may one day destroy it."