"I suppose we should take it that new knowledge should apply new conditions to established fact?" I said this with some diffidence; and I could see that the change in my tone, much against my will, attracted her attention. She evidently understood my wish, for she answered with decision: "If you mean by 'new conditions' any alteration of the compact made between us for to-day--yes, I remember 'without prejudice'--there is nothing in our new knowledge to alter the old ones. Do remember, sir, that this day is one set apart, and nothing that is not a very grave matter indeed can be allowed to alter what is established regarding it." "Then," said I, "at all events let us learn the cipher--our cipher as you very properly called it." "Oh no! surely?" this was said with a rising blush. "Indeed, yes--I am glad to say!" "Take care!" she replied, meaningly, then she added: "Very well! Ours let it be. But really and truly I have no right to its discovery; it makes me feel like a fraud to hear you say so." "Be easy," I replied. "You helped me more than I can say. It was your suggestion to reduce the terms of the biliteral; and it was by that means that I read the cipher. But at any rate when we call it 'ours' it will content me if the word 'ours'"--I could not help repeating the word for it was delight to me; it did not displease her either, though it made her blush--"is applied not to invention but to possession!" "All right," she said. "That is good of you. I cannot argue with you. Amendment accepted! Come, let us get on our wheels again. You have the key of _our_ cipher with you; you can tell me the items one by one, and we will learn them as we go along." And so as we swept round Davan Lake, with the wind behind us driving us along except just before we regained the high road at Dinnet, I repeated the symbols of the reduced biliteral. We went over and over them again and again, till we were unable to puzzle each other questioning up and down, 'dodging' as the school-boys say. Oh, but that ride was delightful! There was some sort of conscious equality between us which I could see my comrade felt as well as myself. Down the falling road we sped almost without effort, our wheels seeming to glide on air. When we came to the bridge over the railway just above Aboyne, where the river comes north and runs in under a bank of shale and rock, we dismounted and looked back. Behind us was our last view of the gorge above Ballater, where the two round hills stood as portals, and where the cloud rack hanging above and beyond made a mystery which was full of delightful fascination and no less delightful remembrance. Then with a sigh we turned. There, before us lay a dark alley between the closing pines. No less mysterious, but seemingly dark and grim. CHAPTER XV A PECULIAR DINNER-PARTY