“You know my methods in such cases, Watson. I put myself in the man’s place, and, having first gauged his intelligence, I try to imagine how I should myself have proceeded under the same circumstances. In this case the matter was simplified by Brunton’s intelligence being quite first-rate, so that it was unnecessary to make any allowance for the personal equation, as the astronomers have dubbed it. He knew that something valuable was concealed. He had spotted the place. He found that the stone which covered it was just too heavy for a man to move unaided. What would he do next? He could not get help from outside, even if he had someone whom he could trust, without the unbarring of doors and considerable risk of detection. It was better, if he could, to have his helpmate inside the house. But whom could he ask? This girl had been devoted to him. A man always finds it hard to realize that he may have finally lost a woman’s love, however badly he may have treated her. He would try by a few attentions to make his peace with the girl Howells, and then would engage her as his accomplice. Together they would come at night to the cellar, and their united force would suffice to raise the stone. So far I could follow their actions as if I had actually seen them.

“But for two of them, and one a woman, it must have been heavy work, the raising of that stone. A burly Sussex policeman and I had found it no light job. What would they do to assist them? Probably what I should have done myself. I rose and examined carefully the different billets of wood which were scattered round the floor. Almost at once I came upon what I expected. One piece, about three feet in length, had a very marked indentation at one end, while several were flattened at the sides as if they had been compressed by some considerable weight. Evidently, as they had dragged the stone up, they had thrust the chunks of wood into the chink until at last when the opening was large enough to crawl through, they would hold it open by a billet placed lengthwise, which might very well become indented at the lower end, since the whole weight of the stone would press it down on to the edge of this other slab. So far I was still on safe ground.

“And now how was I to proceed to reconstruct this midnight drama? Clearly, only one could fit into the hole, and that one was Brunton. The girl must have waited above. Brunton then unlocked the box, handed up the contents presumably - since they were not to be found - and then - and then what happened?

“What smouldering fire of vengeance had suddenly sprung into flame in this passionate Celtic woman’s soul when she saw the man who had wronged her - wronged her, perhaps, far more than we suspected - in her power? Was it a chance that the wood had slipped and that the stone had shut Brunton into what had become his sepulchre? Had she only been guilty of silence as to his fate? Or had some sudden blow from her hand dashed the support away and sent the slab crashing down into its place? Be that as it might, I seemed to see that woman’s figure still clutching at her treasure trove and flying wildly up the winding stair, with her ears ringing perhaps with the muffled screams from behind her and with the drumming of frenzied hands against the slab of stone which was choking her faithless lover’s life out.

“Here was the secret of her blanched face, her shaken nerves, her peals of hysterical laughter on the next morning. But what had been in the box? What had she done with that? Of course, it must have been the old metal and pebbles which my client had dragged from the mere. She had thrown them in there at the first opportunity to remove the last trace of her crime.