My first impression as I opened the door was that a fire had broken out, for the room was so filled with smoke that the light of the lamp upon the table was blurred by it. As I entered, however, my fears were set at rest, for it was the acrid fumes of strong coarse tobacco which took me by the throat and set me coughing. Through the haze I had a vague vision of Holmes in his dressing-gown coiled up in an armchair with his black clay pipe between his lips. Several rolls of paper lay around him.

“Caught cold, Watson?” said he.

“No, it’s this poisonous atmosphere.”

“I suppose it is pretty thick, now that you mention it.”

“Thick! It is intolerable.”

“Open the window, then! You have been at your club all day, I perceive.”

“My dear Holmes!”

“Am I right?”

“Certainly, but how?”

He laughed at my bewildered expression. “There is a delightful freshness about you, Watson, which makes it a pleasure to exercise any small powers which I possess at your expense. A gentleman goes forth on a showery and miry day. He returns immaculate in the evening with the gloss still on his hat and his boots. He has been a fixture therefore all day. He is not a man with intimate friends. Where, then, could he have been? Is it not obvious?”

“Well, it is rather obvious.”

“The world is full of obvious things which nobody by any chance ever observes. Where do you think that I have been?”

“A fixture also.”

“On the contrary, I have been to Devonshire.”

“In spirit?”

“Exactly. My body has remained in this armchair and has, I regret to observe, consumed in my absence two large pots of coffee and an incredible amount of tobacco. After you left I sent down to Stamford’s for the Ordnance map of this portion of the moor, and my spirit has hovered over it all day. I flatter myself that I could find my way about.”

“A large-scale map, I presume?”

“Very large.”

He unrolled one section and held it over his knee. “Here you have the particular district which concerns us. That is Baskerville Hall in the middle.”

“With a wood round it?”