The fire had burned low in the grate and the sun was long since set. I stretched where I sat in my armchair, laying the novel I'd been perusing aside and thinking of retiring. Holmes, it appeared, was bound for another sleepless night of work, engaged as he was in completing his latest chemical study. Thankfully, the experiment itself had been completed the previous evening, and the remaining work saw him occupied by nothing more volatile or disruptive than poring over the data he had catalogued, examining lists of figures in certain notebooks and scribbling equations and diagrams in others.
I had left him immersed in this business earlier that morning, returned that afternoon to find him still about it, and since had not seen him rise from his desk except to pace before the window, the pencil he'd worn down to a stub clenched between his teeth in place of his pipe, eyes distant and intense with thought.
I cast him a bit of a worried glance, now. He was seated again at his desk, his chemical-stained shirtsleeves rolled up to his elbows and his head lain in one hand, long fingers tangled in his already unkempt dark hair, making it stick up all the more on one side. I did not like to see him work at this pitch without rest, but, nonetheless, I confess that as I observed him my expression of worry was exchanged for the ghost of a fond smile. He was in his element this way, I acknowledged. It was true that my unique, remarkable friend was never more himself than when wrestling with some enigma.
It suited him.