The Valley of Fear

dead painting man and the affair at Birlstone?”
“All knowledge comes useful to the detective,” remarked Holmes. “Even the trivial fact that in the year 1865 a picture by Greuze entitled La Jeune Fille à l’Agneau fetched one million two hundred thousand francs⁠—more than forty thousand pounds⁠—at the Portalis sale may start a train of reflection in your mind.”
It was clear that it did. The inspector looked honestly interested.
“I may remind you,” Holmes continued, “that the professor’s salary can be ascertained in several trustworthy books of reference. It is seven hundred a year.”
“Then how could he buy⁠—”
“Quite so! How could he?”
“Ay, that’s remarkable,” said the inspector thoughtfully. “Talk away,  Mr. Holmes. I’m just loving it. It’s fine!”
Holmes smiled. He was always warmed by genuine admiration⁠—the characteristic of the real artist. “What about Birlstone?” he asked.
“We’ve time yet,” said the inspector, glancing at his watch. “I’ve a cab at the door, and it won’t take us twenty minutes to Victoria. But about this picture: I thought you told me once,  Mr. Holmes, that you had never met Professor Moriarty.”
“No, I never have.”
“Then how do you know about his rooms?”
“Ah, that’s another matter. I have been three times in his rooms, twice waiting for him under different pretexts and leaving before he came. Once⁠—well, I can hardly tell about the once to an official detective. It was on the last occasion that I took the liberty of running over his papers⁠—with the most unexpected results.”
“You found something compromising?”
“Absolutely nothing. That was what amazed me. However, you have now seen the point of the picture. It shows him to be a very wealthy man. How did he acquire wealth? He is unmarried. His younger brother is a station master in the west of England. His chair is worth seven hundred a year. And he owns a Greuze.”
“Well?”
“Surely the inference is plain.”
“You mean that he has a great income and that he must earn it in an illegal fashion?”
“Exactly. Of course I have other reasons for thinking so⁠—dozens of exiguous threads which lead vaguely up towards the centre of the web where the poisonous, motionless creature is lurking. I only mention the Greuze because it brings the matter within the range of your own observation.”
“Well,  Mr. Holmes, I admit that what you say is interesting: it’s more than interesting⁠—it’s just wonderful. But let us have it a little clearer if you can. Is it forgery, coining, burglary⁠—where does the money come from?”
“Have you ever read of Jonathan Wild?”
“Well, the name has a familiar sound. Someone in a novel, was he not? I don’t take much stock of detectives in novels⁠—chaps that do things and never let you see how they do them. That’s just inspiration: not business.”
“Jonathan Wild wasn’t a detective, and he wasn’t in a novel. He was a master criminal, and he lived last century⁠—1750 or thereabouts.”
“Then he’s no use to me. I’m a practical man.”
“ Mr. Mac, the most practical thing that you ever did in your life would be to shut yourself up for three months and read twelve hours a day at the annals of crime. Everything comes in circles⁠—even Professor Moriarty. Jonathan Wild was the hidden force of the London criminals, to whom he sold his brains and his organization on a fifteen percent commission. The old wheel turns, and the same spoke comes up. It’s all been done before, and will be again. I’ll tell you one or two things about Moriarty which may interest you.”
“You’ll interest me, right enough.”
“I happen to know who is the first link in his chain⁠—a chain with this Napoleon-gone-wrong at one end, and a hundred broken fighting men, pickpockets, blackmailers, and card sharpers at the other, with every sort of crime in between. His chief of staff is Colonel Sebastian Moran, as aloof and guarded and inaccessible to the law as himself. What do you think he pays him?”
“I’d like to hear.”
“Six thousand a year. That’s paying for brains, you see⁠—the American business principle. I learned that detail quite by chance. It’s more than the Prime Minister gets. That gives you an idea of Moriarty’s gains and of the scale on which he works. Another point: I made it my business to hunt down some of Moriarty’s checks lately⁠—just common innocent checks that he pays his household bills with. They were drawn on six different banks. Does that make any impression on your mind?”
“Queer, certainly! But what do you gather from it?”
“That he wanted no gossip about his wealth. No single man should know what he had. I have no doubt that he has twenty banking accounts; the bulk of his fortune abroad in the Deutsche Bank or the Crédit Lyonnais as likely as not. Sometime when you have a year or two to spare I commend to you the study of Professor Moriarty.”
Inspector MacDonald had grown steadily more impressed as the conversation proceeded. He had lost himself in his interest. Now his practical Scotch intelligence brought him back with a snap to the matter in hand.
“He can keep, anyhow,” said he. “You’ve got us sidetracked with your interesting anecdotes,  Mr. Holmes. What really counts is your remark that there is some connection between the professor and the crime. That you get from the warning received through the man Porlock. Can we for our present practical needs get any further than that?”
“We may form some conception as to the motives of the crime. It is, as I gather from your original remarks, an inexplicable, or at least an unexplained, murder. Now, presuming that the source of the crime is as we suspect it to be, there might be two different motives. In the first place, I may tell you that Moriarty rules with a rod of iron over his people. His discipline is tremendous. There is only one punishment in his code. It is death. Now we might suppose that this murdered man⁠—this Douglas whose approaching fate was known by one of the arch-criminal’s subordinates⁠—had in some way betrayed the chief. His punishment followed, and would be