The thought had hardly passed through my mind when the man whom we were watching caught sight of the number on our door, and ran rapidly across the roadway. We heard a loud knock, a deep voice below, and heavy steps ascending the stair.

“For Mr. Sherlock Holmes,” he said, stepping into the room and handing my friend the letter.

Here was an opportunity of taking the conceit out of him. He little thought of this when he made that random shot. “May I ask, my lad,” I said, in the blandest voice, “what your trade may be?”

“Commissionaire, sir,” he said, gruffly. “Uniform away for repairs.”

“And you were?” I asked, with a slightly malicious glance at my companion.

“A sergeant, sir, Royal Marine Light Infantry, sir. No answer? Right, sir.”

He clicked his heels together, raised his hand in salute, and was gone.