“We must fall back upon the old axiom that when all other contingencies fail, whatever remains, however improbable, must be the truth. Here all other contingencies have failed. When I found that the leading international agent, who had just left London, lived in a row of houses which abutted upon the Underground, I was so pleased that you were a little astonished at my sudden frivolity.”
“Oh, that was it, was it?”
“Yes, that was it. Mr. Hugo Oberstein, of 13, Caulfield Gardens, had become my objective. I began my operations at Gloucester Road Station, where a very helpful official walked with me along the track, and allowed me to satisfy myself, not only that the back-stair windows of Caulfield Gardens open on the line, but the even more essential fact that, owing to the intersection of one of the larger railways, the Underground trains are frequently held motionless for some minutes at that very spot.”
“Splendid, Holmes! You have got it!”
“So far—so far, Watson. We advance, but the goal is afar. Well, having seen the back of Caulfield Gardens, I visited the front and satisfied myself that the bird was indeed flown. It is a considerable house, unfurnished, so far as I could judge, in the upper rooms. Oberstein lived there with a single valet, who was probably a confederate entirely in his confidence. We
