You have not forgotten last night already?"

"Dyson," said the other, speaking very seriously, "I have been turning it over in my mind this morning while you have been out. I have thought about what I saw, or perhaps I should say about what I thought I saw, and the only conclusion I can come to is this, that the thing won't bear recollection. As men live, I have lived soberly and honestly, in the fear of God, all my days, and all I can do is believe that I suffered from some monstrous delusion, from some phantasmagoria of the bewildered senses. You know we went home together in silence, not a word passed between us as to what I fancied I saw; had we not better agree to keep silence on the subject? When I took my walk in the peaceful morning sunshine, I thought all the earth seemed full of praise, and passing by that wall I noticed there were no more signs recorded, and I blotted out those that remained. The mystery is over, and we can live quietly again. I think some poison has been working for the last few weeks; I have trod on the verge of madness, but I am sane now."

Mr. Vaughan had spoken earnestly, and bent forward in his chair and glanced at Dyson with something of entreaty.

"My dear Vaughan," said the other, after a pause, "what's the use of this? It is much too late to take that tone; we have gone too deep. Besides you know as well as I that there is no delusion in the case; I wish there were with all my heart. No, in justice to myself I must tell you the whole story, so far as I know it."

"Very good," said Vaughan with a sigh, "if you must, you must."

"Then," said Dyson, "we will begin with the end if you please. I found this brooch you have just identified in the place we have called the Bowl. There was a heap of grey ashes, as if a fire had been burning, indeed, the embers were still hot, and this brooch was lying on the ground, just outside the range of the flame. It must have dropped accidentally from the dress of the person who was wearing it. No, don't interrupt me; we can pass now to the beginning, as we have had the end. Let us go back to that day you came to see me in my rooms in London. So far as I can remember, soon after you came in you mentioned, in a somewhat casual manner, that an unfortunate and mysterious incident had occurred in your part of the country; a girl named Annie Trevor had gone to see a relative, and had disappeared. I confess freely that what you said did not greatly interest me; there are so many reasons which may make it extremely convenient for a man and more especially a woman to vanish from the circle of their relations and friends. I suppose, if we were to consult the police, one would find that in London somebody disappears mysteriously every other week, and the officers would, no doubt, shrug their shoulders, and tell you that by the law of averages it could not be otherwise. So I was very culpably careless to your story, and besides, here is another reason for my lack of interest; your tale was inexplicable. You could only suggest a blackguard sailor on the tramp, but I discarded the explanation immediately.

For many reasons, but chiefly because the occasional criminal, the amateur in brutal crime, is always found out, especially if he selects the country as the scene of his operations. You will remember the case of that Garcia you mentioned; he strolled into a railway station the day after the murder, his trousers covered with blood, and the works of the Dutch clock, his loot, tied in a neat parcel. So rejecting this, your only suggestion, the whole tale became, as I say, inexplicable, and, therefore, profoundly uninteresting. Yes, therefore, it is a perfectly valid conclusion. Do you ever trouble your head about problems which you know to be insoluble? Did you ever bestow much thought on the old puzzle of Achilles and the tortoise? Of course not, because you knew it was a hopeless quest, and so when you told me the story of a country girl who had disappeared I simply placed the whole thing down in the category of the insoluble, and thought no more about the matter. I was mistaken, so it has turned out; but if you remember, you immediately passed on to an affair which interested you more intensely, because personally, I need not go over the very singular narrative of the flint signs, at first I thought it all trivial, probably some children's game, and if not that a hoax of some sort; but your showing me the arrowhead awoke my acute interest. Here, I saw, there was something widely removed from the commonplace, and matter of real curiosity; and as soon as I came here I set to work to find the solution, repeating to myself again and again the signs you had described. First came the sign we have agreed to call the Army; a number of serried lines of flints, all pointing in the same way. Then the lines, like the spokes of a wheel, all converging towards the figure of a Bowl, then the triangle or Pyramid, and last of all the Half moon. I confess that I exhausted conjecture in my efforts to unveil this mystery, and as you will understand it was a duplex or rather triplex problem. For I had not merely to ask myself: what do these figures mean? but also, who can possibly be responsible for the designing of them? And again, who can possibly possess such valuable things, and knowing their value thus throw them down by the wayside? This line of thought led me to suppose that the person or persons in question did not know the value of unique flint arrowheads, and yet this did not lead me far, for a well-educated man might easily be ignorant on such a subject. Then came the complication of the eye on the wall, and you remember that we could not avoid the conclusion that in the two cases the same agency was at work.