10
The return journey to London passed quietly.
Holmes spent much of it with his eyes closed, his long legs stretched before him in the railway compartment, his pipe held motionless between his fingers.
A casual observer might have supposed him asleep.
I knew better. There were certain signs which invariably betrayed the intense activity of his mind, and I had learned through long experience not to interrupt such periods of silent concentration.
Even after our arrival at Baker Street, his mood remained unchanged.
For the next two days Holmes did little beyond think, smoke, and generally brood.
The Persian slipper containing his tobacco seemed never to leave his reach, while the air of our sitting room gradually became blue with the fragrant haze of his black shag.
At intervals he would pace slowly from the fireplace to the window, only to return again without having uttered a word.
At other times he remained for several hours together in his armchair, his keen features half hidden behind drifting clouds of smoke, his eyes fixed upon nothing that I could perceive.
I could not recall another investigation which had affected him in quite the same fashion.
There was no shortage of unsolved murders in Holmes's remarkable career, nor even of dying messages left by victims. Yet this affair appeared to possess some peculiar quality which continually drew his thoughts back to it.
More than once I heard him murmur almost beneath his breath,
"Beware the coffin."
The words had begun to haunt my own imagination scarcely less than his.
I found myself returning again and again to that little cemetery behind the ancient yew trees.
One of those forgotten coffins.
It seemed impossible to escape the conclusion.
But what danger could possibly lie within it?
I even caught myself wondering whether some ingenious mechanical trap might have survived the centuries.
Could Professor Stratton, in the course of his historical researches, have discovered some hidden device—perhaps even an old explosive contrivance—concealed within one of the coffins?
If so, how had he stumbled upon it? And, more importantly still, who had learned of his discovery quickly enough to silence him forever—and why?
Such speculations frequently occupied me before I became uncomfortably aware of what I was doing.
I was committing Holmes's cardinal error.
Again and again I had heard him warn against constructing theories before one possessed sufficient facts to support them. Yet here was I inventing hidden mechanisms, imaginary discoveries, and unknown murderers upon no firmer foundation than three dying words spoken in a cemetery.
With a rueful smile I abandoned the exercise.
There remained only one fact of which I could be certain.
Professor Stratton, as life ebbed from him, had struggled to utter a final warning.
Beware the coffin.
The words were plain enough.
It was only their actual meaning that remained maddeningly beyond our reach.