Chapter 30: The Watson Conjecture

The letter arrived on a Thursday, which Watson would later note was the same day of the week he had first signed the Montague Street lease, though he did not attach significance to this until much later, and even then was uncertain whether the significance was real or constructed in retrospect by a mind that had spent too long looking for patterns.

It came in the afternoon post, tucked between a bill from his coal merchant and a circular from a medical society he had neglected to resign from following the disruption of the autumn. The envelope was cream, medium weight, Continental in origin — he had learned to recognise the paper stock from Adelaide's analysis in October, and the recognition was now automatic, a reflex that would probably never fully leave him. There was no return address. The postmark read Zürich, which told him very little, since Irene Adler would not be in Zürich by the time he read it and had presumably known this when she chose the posting city.

He set it on the desk and looked at it for a moment.