As Thorndyke and I arrived at the main gateway of the Temple and he swung round into the narrow lane, it was suddenly borne in on me that I had made no arrangements for the night. Events had followed one another so continuously and each had been so engrossing that I had lost sight of what I may call my domestic affairs.  
"We seem to be heading for your chambers, Thorndyke," I ventured to remark. "It is a little late to think of it, but I have not yet settled where I am to put up to-night."
 
"My dear fellow," he replied, "you are going to put up in your own bedroom which has been waiting in readiness for you ever since you left it. Polton went up and inspected it as soon as you arrived. I take it that you will consider my chambers yours until such time as you may join the benedictine majority and set up a home for yourself."
 
"That is very handsome of you," said I. "You didn't mention that the billet you offered was a resident appointment."
 
"Rooms and commons included," said Thorndyke; and when I protested that I should at least contribute to the costs of living he impatiently waved the suggestion away. We were still arguing the question when we reached our chambers—as I will now call them—and a diversion was occasioned by my taking the lamp from my pocket and placing it on the table.
 
"Ah," my colleague remarked, "that is a little reminder. We will put it on the mantelpiece for Polton to collect and you shall give me a full account of your further adventures in the wilds of Kennington. That was a very odd affair. I have often wondered how it ended."
 
He drew our two arm-chairs up to the fire, put on some more coal, placed the tobacco jar on the table exactly equidistant from the two chairs, and settled himself with the air of a man who is anticipating an agreeable entertainment.
 
I filled my pipe, and, taking up the thread of the story where I had broken off on the last occasion, began to outline my later experiences. But he brought me up short.
 
"Don't be sketchy, Jervis. To be sketchy is to be vague. Detail, my child, detail is the soul of induction. Let us have all the facts. We can sort them out afterwards."
 
I began afresh in a vein of the extremest circumstantiality. With deliberate malice I loaded a prolix narrative with every triviality that a fairly retentive memory could rake out of the half-forgotten past. I cudgelled my brains for irrelevant incidents. I described with the minutest accuracy things that had not the faintest significance. I drew a vivid picture of the carriage inside and out; I painted a lifelike portrait of the horse, even going into particulars of the harness—which I was surprised to find that I had noticed. I described the furniture of the dining-room and the cobwebs that had hung from the ceiling; the auction-ticket on the chest of drawers, the rickety table and the melancholy chairs. I gave the number per minute of the patient's respirations and the exact quantity of coffee consumed on each occasion, with an exhaustive description of the cup from which it was taken; and I left no personal details unconsidered, from the patient's finger-nails to the roseate pimples on Mr. Weiss's nose.
 
But my tactics of studied prolixity were a complete failure. The attempt to fatigue Thorndyke's brain with superabundant detail was like trying to surfeit a pelican with whitebait. He consumed it all with calm enjoyment and asked for more; and when, at last, I did really begin to think that I had bored him a little, he staggered me by reading over his notes and starting a brisk cross-examination to elicit fresh facts! And the most surprising thing of all was that when I had finished I seemed to know a great deal more about the case than I had ever known before.
 
"It was a very remarkable affair," he observed, when the cross-examination was over—leaving me somewhat in the condition of a cider-apple that has just been removed from a hydraulic press—"a very suspicious affair with a highly unsatisfactory end. I am not sure that I entirely agree with your police officer. Nor do I fancy that some of my acquaintances at Scotland Yard would have agreed with him."
 
"Do you think I ought to have taken any further measures?" I asked uneasily.
 
"No; I don't see how you could. You did all that was possible under the circumstances. You gave information, which is all that a private individual can do, especially if he is an overworked general practitioner. But still, an actual crime is the affair of every good citizen. I think we ought to take some action."
 
"You think there really was a crime, then?"
 
"What else can one think? What do you think about it yourself?"
 
"I don't like to think about it at all. The recollection of that corpse-like figure in that gloomy bedroom has haunted me ever since I left the house. What do you suppose has happened?"
 
Thorndyke did not answer for a few seconds. At length he said gravely:
 
"I am afraid, Jervis, that the answer to that question can be given in one word."
 
"Murder?" I asked with a slight shudder.
 
He nodded, and we were both silent for a while.
 
"The probability," he resumed after a pause, "that Mr. Graves is alive at this moment seems to me infinitesimal. There was evidently a conspiracy to murder him, and the deliberate, persistent manner in which that object was being pursued points to a very strong and definite motive. Then the tactics adopted point to considerable forethought and judgment. They are not the tactics of a fool or an ignoramus. We may criticize the closed carriage as a tactical mistake, calculated to arouse suspicion, but we have to weigh it against its alternative."
 
"What is that?"
 
"Well, consider the circumstances. Suppose Weiss had called you in in the ordinary way. You would still have detected the use of poison. But now you could have located your man and made inquiries about him in the neighbourhood. You would probably have given the police a hint and they would almost certainly have taken action, as they would have had the means of identifying the parties. The result would have been fatal to Weiss. The closed carriage invited suspicion, but it was a great safeguard. Weiss's method's were not so unsound after all. He is a cautious man, but cunning and very persistent. And he could be bold on occasion. The use of the blinded carriage was a decidedly audacious proceeding. I should put him down as a gambler of a very discreet, courageous and resourceful type."
 
"Which all leads to the probability that he has pursued his scheme and brought it to a successful issue."
 
"I am afraid it does. But—have you got your notes of the compass-bearings?"
 
"The book is in my overcoat pocket with the board. I will fetch them."
 
I went into the office, where our coats hung, and brought back the notebook with the little board to which it was still attached by the rubber band. Thorndyke took them from me, and, opening the book, ran his eye quickly down one page after another. Suddenly he glanced at the clock.
 
"It is a little late to begin," said he, "but these notes look rather alluring. I am inclined to plot them out at once. I fancy, from their appearance, that they will enable us to locate the house without much difficulty. But don't let me keep you up if you are tired. I can work them out by myself."
 
"You won't do anything of the kind," I exclaimed. "I am as keen on plotting them as you are, and, besides, I want to see how it is done. It seems to be a rather useful accomplishment."
 
"It is," said Thorndyke. "In our work, the ability to make a rough but reliable sketch survey is often of great value. Have you ever looked over these notes?"
 
"No. I put the book away when I came in and have never looked at it since."
 
"It is a quaint document. You seem to be rich in railway bridges in those parts, and the route was certainly none of the most direct, as you noticed at the time. However, we will plot it out and then we shall see exactly what it looks like and whither it leads us."
 
He retired to the laboratory and presently returned with a T-square, a military protractor, a pair of dividers and a large drawing-board on which was pinned a sheet of cartridge paper.
 
"Now," said he, seating himself at the table with the board before him, "as to the method. You started from a known position and you arrived at a place the position of which is at present unknown. We shall fix the position of that spot by applying two factors, the distance that you travelled and the direction in which you were moving. The direction is given by the compass; and, as the horse seems to have kept up a remarkably even pace, we can take time as representing distance. You seem to have been travelling at about eight miles an hour, that is, roughly, a seventh of a mile in one minute. So if, on our chart, we take one inch as representing one minute, we sha............