"You mustn't imagine anything like that, General," I advised seriously. "Whatever you do, don't encourage any doubts of your own sanity. There must be some explanation of this, although I can't for the moment imagine what it can possibly be. It is a remarkable thing, and I fancy you will find, when we do know the explanation, that anyone else standing where you were at that time would have seen exactly the same thing. The rock stands out of the water; it is just above a deep pool, and probably it was a sort of mirage effect, and not by any means a figment of your brain." To my surprise the old man leaned back in his chair and burst out laughing. "Of course," he exclaimed. "I never thought of that--a sort of mirage. Well, I'm begad thankful you suggested that, Ronald. I've no doubt that it was something of the sort. What a begad old fool I am. Let us pray that our poor little girl's trouble," he added solemnly, "will have some equally simple solution." The General was so relieved that I had given him, at any rate, some sort of reason to believe that his brain was not yet going, that he began to declare that he was convinced Myra would be better in a day or two. So we arranged that I should take her up to London the next day, and leave her in charge of her aunt, Lady Ruslit, and then, as soon as we had heard Sir Gaire's verdict, I was to bring her back again. General McLeod had been anxious at first to come with us, but I pointed out that he would be of more use to Myra if he stayed behind, and kept an eye on her interests in the neighbourhood. I promised to wire him the result of the interview with Olvery as soon as I knew it. And just about a quarter to ten we went to bed. "Ronald," said the old man, as we shook hands outside my door, "there's just one thing I wasn't frank with you about in the matter of the Chemist's Rock. I am anxious to believe that it's a point of no particular importance. You know the rock is a sort of sandstone, not grey like the rest, but nearly white?" "Yes," I answered, wondering what could be coming next. "Well," said the old man, "that day when I saw it appearing to come towards me it was not white, but green." "No," I said at last, when we had spent another twenty minutes discussing this new aspect in my room. "It's beyond me. I can't see how the two events can be connected, and yet they are so unusual that one would think they must be. I certainly think it is a point to put in detail before Olvery." "On the whole, I quite agree with you," said the General. "I am rather afraid he may take us for a pack of lunatics, and refuse to be bothered with the case."