“My dear Jervis,” said he, “you and Marchmont are allowing yourselves to be obsessed by a particular fact—a very striking and weighty fact, I will admit, but still, only an isolated fact. Jeffrey Blackmore executed his will in a regular manner, complying with all the necessary formalities and conditions. In the face of that single circumstance you and Marchmont would ‘chuck up the sponge,’ as the old pugilists expressed it. Now that is a great mistake. You should never allow yourself to be bullied and browbeaten by a single fact.”
“But, my dear Thorndyke!” I protested, “this fact seems to be final. It covers all possibilities—unless you can suggest any other that would cancel it.”
“I could suggest a dozen,” he replied. “Let us take an instance. Supposing Jeffrey executed this will for a wager; that he immediately revoked it and made a fresh will, that he placed the latter in the custody of some person and that that person has suppressed it.”
“Surely you do not make this suggestion seriously!” I exclaimed.
“Certainly I do not,” he replied with a smile. “I merely give it as an instance to show that your final and absolute fact is really only conditional on there being no other fact that cancels it.”
“Do you think he might have made a third will?”
“It is obviously possible. A man who makes two wills may make three or more; but I may say that I see no present reason for assuming the existence of another will. What I want to impress on you is the necessity of considering all the facts instead of bumping heavily against the most conspicuous one and forgetting all the rest. By the way, here is a little problem for you. What was the object of which these are the parts?”
He pushed across the table a little cardboard box, having first removed the lid. In it were a number of very small pieces of broken glass, some of which had been cemented together by their edges.
“These, I suppose,” said I, looking with considerable curiosity at the little collection, “are the pieces of glass that we picked up in poor Blackmore’s bedroom?”
“Yes. You see that Polton has been endeavouring to reconstitute the object, whatever it was; but he has not been very successful, for the fragments were too small and irregular and the collection too incomplete. However, here is a specimen, built up of six small pieces, which exhibits the general character of the object fairly well.”
He picked out the little irregularly shaped object and handed it to me; and I could not but admire the neatness with which Polton had joined the tiny fragments together.
I took the little “restoration,” and, holding it up before my eyes, moved it to and fro as I looked through it at the window.
“It was not a lens,” I pronounced eventually.
“No,” Thorndyke agreed, “it was not a lens.”
“And so cannot have been a spectacle-glass. But the surface was curved—one side convex and the other concave—and the little piece that remains of the original edge seems to have been ground to fit a bezel or frame. I should say that these are portions of a watch-glass.”
“That is Polton’s opinion,” said Thorndyke, “and I think you are both wrong.”
“What do you say to the glass of a miniature or locket?”
“That is rather more probable, but it is not my view.”
“What do you think it is?” I asked. But Thorndyke was not to be drawn.
“I am submitting the problem for solution by my learned friend,” he replied with an exasperating smile, and then added: “I don’t say that you and Polton are wrong; only that I don’t agree with you. Perhaps you had better make a note of the properties of this object, and consider it at your leisure when you are ruminating on the other data referring to the Blackmore case.”
“My ruminations,” I said, “always lead me back to the same point.”
“But you mustn’t let them,” he replied. “Shuffle your data about. Invent hypotheses. Never mind if they seem rather wild. Don’t put them aside on that account. Take the first hypothesis that you can invent and test it thoroughly with your facts. You will probably have to reject it, but you will be certain to have learned something new. Then try again with a fresh one. You remember what I told you of my methods when I began this branch of practice and had plenty of time on my hands?”
“I am not sure that I do.”
“Well, I used to occupy my leisure in constructing imaginary cases, mostly criminal, for the purpose of study and for the acquirement of experience. For instance, I would devise an ingenious fraud and would plan it in detail, taking every precaution that I could think of against failure or detection, considering, and elaborately providing for, every imaginable contingency. For the time being, my entire attention was concentrated on it, making it as perfect and secure and undetectable as I could with the knowledge and ingenuity at my command. I behaved exactly as if I were proposing actually to carry it out, and my life or liberty depended on its success—excepting that I made full notes of every detail of the scheme. Then when my plans were as complete as I could make them, and I could think of no way in which to improve them, I changed sides and considered the case from the standpoint of detection. I analysed the case, I picked out its inherent and unavoidable weaknesses, and, especially, I noted the respects in which a fraudulent proceeding of a particular kind differed from the bona fide proceeding that it simulated. The exercise was invaluable to me. I acquired as much experience from those imaginary cases as I should from real ones, and in addition, I learned a method which is the one that I practise to this day.”
“Do you mean
