Part 19

"Very well," said Hewitt, "then my part of the business is done, though I must say I've had luck, or rather, Brett has had it for me. But the police must come on now. I think, Mr. Bell, we'll go along to Scotland Yard when we leave here. They'll be wanting to see Mr. Catherton Hunt, I expect, whoever he is--and somebody in your office, too, if I'm not sadly mistaken."

"Who?" gasped Mr. Bell.

"That, perhaps, you can help to point out. See here--do you know whose figures they are?" and Hewitt produced the small slip of paper containing the cypher.

"They're very small," remarked Mr. Bell, putting on his glasses; "very small indeed; but I think--why they're Henning's, I do believe!"

"Ah! one or two other little things seemed to point that way. Henning is your correspondence clerk, I believe, and I expect this thin little slip is a specimen of your typewriter paper. Have you any of his written figures for comparison?"

"Well no--I hardly think--you see he typewrites his letters, and although I know his writing very well I can't at the moment put my hand on any figures of his."

"Never mind--it's mere matter of curiosity; the police will ask him questions in the morning. What I believe has happened is this. Our friend Henning--if he's the man--has a friend outside a great deal cleverer than himself--though he would seem to have his share of cunning, too. Between them they resolved to rob you in the way they have done--temporarily. Henning was to take advantage of his position in that little inner room to get at the safe some day when it was open and when you were engaged in your own private inner room with a client, so leaving the safe unwatched. He was provided with a spare patent padlock and key, of the sort you used on that black box, and his confederate had drilled him in the trick of breaking that particular sort of padlock open, with other spare specimens. He got his opportunity this morning."

"Only this morning?"

"This morning, I think, else we should never have got these bonds back, nor even have heard of them again. I think you said you were engaged with a client for half an hour?"

"Yes, from about half-past ten to eleven."

"That was his chance, and he took it. He broke the padlock, took out the bonds, substituted the dummies he had already prepared in his own desk, and locked the box again with the new padlock. Meantime Hunt had paid a deposit, pending references, on the office below--the nearest empty room. Of course, he wouldn't get the key until the tenancy was finally accepted--which he never intended it should be. But he easily arranged to have the door left unlocked for a day or two, on some convenient excuse--arranging decorations, or what not. And the bill was taken down, so that prospective and prospecting tenants were kept away. The bonds being stolen, Henning took the first opportunity of carrying them to the empty office--probably piecemeal--a thing he could easily manage almost under your nose, before you were aware of your loss. There he was to conceal them, either in the chimney, under the boards, or in the ventilator, as he might find convenient--and he found the ventilator most convenient. Then he was to apprise his confederate of the fact that the robbery had been effected in order that Hunt might come and quietly fetch the plunder away. The message was to take an ingenious form. Hunt was to have a fellow waiting about in the street, and as soon as Henning could get out--say to lunch--he was just to send the key by this messenger--the key with which he had locked the new padlock on the black box. You see the advantages of that simple arrangement. First, the key, which is evidence, is got rid of in a safe and effectual way--a thing that couldn't be done as well by merely flinging it away on or near the premises, where it might be found. Next, the message is perfectly secret--the messenger could never guess what the key meant, nor could any other person not in the confederate's confidence. And, at the same time, the key tells all that is necessary; the robbery has been effected--come and remove the plunder.

"But something unforeseen happens. No sooner are the bonds stolen and safely hidden than you go to the box, find something wrong with the lock, break it open and discover the loss. This was a thing that they trusted would not happen till after the bonds were safely got away. More, I am sent for, the clerks are kept in from lunch, and so on. Henning gets into a funk, and resolves to send a message of special urgency to his confederate. For that purpose he uses a cypher which the two have agreed upon--the most ingenious cypher I have ever seen used for the purpose. He doesn't wish to make his message any more conspicuous than he need, so he writes his cypher on this scrap of paper and rolls it inside the key--probably another expedient agreed upon in case of necessity. Then the key goes into an envelope, for greater security of the cypher message, and the messenger gets it when Henning is at last released for lunch. What happened to the message we know; and here it is.

"Now I will not weary you with a detailed account of the different ways in which I attacked this cypher, but I will take the shortest possible cut to the true interpretation. A very short examination of the cryptogram shows that while no number is included above 23, the numbers, in their relative frequency, roughly agree with the relative frequency of the corresponding letters of the alphabet, a for 1, b for 2, and so on."

Here I handed Hewitt the pencilled note I had made at the hospital, with letters substituted for the figures, thus:--i, h, n, d, t, r, e, i; o, s, t, 0, c, i, h, e; c, w, 0, 0, e, m, n, s; s, t, 0, 0, 0, 0, f, a; e, t, 0, 0, 0, 0, c, v; a, o, 0, 0, 0, 0, r, e; a, h, t, k, r, i, e, t; l, e, w, n, n, a, a, t.

Hewitt took the paper and went on. "If that were all the thing would be childishly simple. But you will see that we seem as far from the solution as ever; for the letters as they stand mean nothing, though in fact they are in normal relative frequency; so that if they mean other letters, all the rules are upset, and we are at a standstill. I admit that for a long time the thing bothered me. But a peculiarity struck me. Not only were the figures, or letters, disposed in groups of eight, but there were also eight such groups--sixty-four altogether. What did that suggest? What but a chessboard?"

"A chessboard?" I queried.

"Just so--a chessboard. Eight squares each way--sixty-four altogether. So I drew a rough representation of a chessboard, and set out the letters on it, in their order, like this:--

i h n d t r e i o s t O c i h e c w 0 0 e m n s s t 0 o o 0 f a e t 0 o o 0 c v a o 0 o o 0 r e a h t k r i e t l e w n n a a t

"Now, there was my chessboard with my letters on it. I tried reading them downward, across, upward and diagonally, in the direction of the moves of different chess pieces--king, queen, rook and bishop. Nothing came of that, whatever I did; the thing was as unreadable as ever. But there remained one chess-move to try--the eccentric move of the knight; the move of one square forward, backward or sideways, and then one square diagonally, or, as it has sometimes been more concisely expressed, the move to the next square but one of a different colour from that on which it rests. I tried the knight's move, and I read the cypher.

"I began at the top left-hand corner, just as one does in reading a book. I read the moves downward--i to w, e and h, and found that led to nothing. So I took the one alternative move, and, with a little consideration, skipped along from i to t in the second line of squares, t in the top line, h in the second line, e in the third, r in the top and e in the second. That gave me an idea. There were the letters i, t, t, followed by the word here. I tried back from the i again, and taking in the reverse order the w, e and h which I had first given up, I read my own name, as you can see it, from the h on the bottom line but one, moving upward. So I had the words Hewitt here. I need not carry you through all the steps, which will now be plain enough to you. But I found that the message actually began in the right-hand corner, and read thus, the noughts counting for nothing--

"'Invent loss disc take at once Martin Hewitt here fear watch.'

"The noughts were plainly merely inserted to fill in unneeded squares, and keep the rest of the figures in their proper relative places when the cypher was written in line. At first I was a little puzzled to understand what seemed to be the first word invent. But it was quite clear that loss disc meant 'loss discovered,' so I concluded that here in the beginning was a contraction also, and that in was a separate word. In that case vent could be a contraction for no other word but 'ventilator,' in accordance with the sense of the words. So I concluded that the meaning of the whole sentence was simply this: 'The plunder is in the ventilator, the loss is discovered, take away the booty at once; Martin Hewitt is here, and I fear I may be watched.' There is the reading, and our little adventure this evening is what it has led to.

"Of course, the confederate wouldn't go groping about the squares so painfully as I have had to do. To him the reading would be simple enough, for the order of the moves would be preconcerted. Each of the conspirators would have, as a guide, both to reading and writing the cypher, a drawn set of squares, numbered in the order of the moves--1 where we have the i, 2 where we have the n, 3 where we have the v, and so on. With that before him, either reading or writing in this extraordinary cryptogram would be easy and quick enough. And now for Scotland Yard!"

We learned late on the following day that Henning had not appeared at the office. From that we assumed that he must have met his confederate in the evening, and, finding that he had not received the message sent, conceived that something was wrong, and made himself safe. The confederate, Hunt, however, made his appearance early next morning, but escaped.

What happened is best told in Plummer's words when he called on Hewitt in the afternoon.

"I went round this morning," he said, "as I said I would last night. I took a good man with me, and we got the dummy bonds that had been put in Bell's box and popped 'em in the ventilator, where the real ones had been hidden. You see, we'd got nothing legal against Catherton Hunt as yet, but if we could only grab him with those dummy bonds on him it might help, with the other evidence we could scrape up (and especially if we could take Henning), to sustain a charge of conspiracy to steal. Well, he came so quick he was on us before we were quite ready. We'd got the dummies in their place, and I was in front of the door telling my man the likeliest corner to wait in, when suddenly up pops the lift right in front of me, with a gentleman in it--clean-shaven. I looked at him and he looked at me. I had a sort of distant notion that I might have seen him before, and it's pretty certain he had something more than a distant notion about me. 'Down again,' he says to the lift man, before the gate was swung, 'I've forgotten something!' And down the lift went. You'll understand I had no idea he was the man we wanted; but as the lift went down and my eyes were on the man's face, I saw who he was! When he stood straight before me I had no more than a vague notion that I'd seen him somewhere before. But down the lift went, and in the flash of time when he'd nearly disappeared, and the bottom part of his face was hidden by the sill of the lift opening--the part of his face where his beard had been when we met him last--I saw it was Myatt!"

"Myatt? Good heavens!"

"Everard Myatt, Mr. Hewitt, the man that murdered Mr. Jacob Mason! Everard Myatt, for a thousand, with his beard shaved! And we've lost him again! What could we do? We shouted and ran downstairs, and that was all. He'd gone, of course. And when we asked the hall porter he told us that Mr. Catherton Hunt had just come down the lift and hurried out!"