He took off his boots and left them at the door, although his wet socks left prints behind on the stone floor. He began a process I had witnessed many times before. I thought of it as his strange dance of detection, in which he moved with great animation and a kind of electrified focus, examining minutely even the most prosaic and benign objects, and from them piecing together a complete and detailed sequence of events.

As usual, I was relegated to the position of observer – and in this case, lookout. If a crime had been committed here, I could as yet see nothing of it.

Holmes took out his lens and worked his way around the small, neat room.

From the doorway, the desk, like everything else, looked pristine. Holmes ran his finger across the top, sides and back, examined and smelled the inside of the drawer. He picked up the bottle of purple ink Buttons had used in the doll incident, now paired next to the original black bottle on the desk. ‘Half empty,’ he remarked. ‘Cap is cracked.’ He flipped through a Bible with numerous small bits of paper marking pages. Noting something on the wall, he scraped it with a fingernail. Then he picked up a candle which had been knocked from its holder and lay on the desk.

The deacon’s small carpet-bag stood upright in the same corner. Empty.

Holmes spent a long time on the bed. Folding back the coverlet, he removed a small card from his pocket, gently brushed something into it, folded it, and replaced it in his pocket. He smelled the pillow, examined the coverlet in minute detail, removed it and examined between the sheets. He moved the bed away from the wall and carefully inspected the newly uncovered area.

At the washstand, he picked up a water-jug. ‘Ah!’ he said, then ran his hands along the back of the desk chair, the arms of the chair, the desk and its drawers. He dropped to the floor, crawled to the corners, looked under the bed and desk, and finally got up, dusting off his clothing.

The window remained open and a steady spray of small droplets pattered against it, some wetting the sill and the stone floor directly below. Holmes re-examined the sill, the lock, the edges of this window, nodding and murmuring something unintelligible as he did so.

It took no incisive deductions on my part to see that some invisible history was playing out vividly in his mind.

He turned to look at me and exclaimed in surprise. He dashed across the small room towards me and minutely examined an area of the wall abutting the doorframe. ‘Your pocketknife, Watson,’ he commanded. ‘I have forgotten mine.’

I complied. He scraped something from the edge of the doorframe. ‘Aha!’ The scrapings went into a second small card which he folded and placed in his pocket.