“Yes; if nothing further happens. But if you should be sent for again, I think it is your duty to make further observations with a view, if necessary, to informing the police. It may be, for instance, of vital importance to identify the house, and it is your duty to secure the means of doing so.”

“But, my dear Thorndyke,” I expostulated, “I have told you how I was conveyed to the house. Now, will you kindly explain to me how a man, boxed up in a pitch-dark carriage, is going to identify any place to which he may be carried?”

“The problem doesn’t appear to me to present any serious difficulties,” he replied.

“Doesn’t it?” said I. “To me it looks like a pretty solid impossibility. But what do you suggest? Should I break out of the house and run away up the street? Or should I bore a hole through the shutter of the carriage and peep out?”