Have His Carcase

NAP DZMTB N.B. OBE XMG SREFZ DBS AM IMHY GAKY R. MULBY M.S. SZLKO GKG LKL GAW XNTED BHMB XZD NRKZH PSMSKMN A.M. MHIZP DK MIM, XNKSAK C KOK MNRL CFL INXF HDA GAIQ.

GATLM Z DLFA A QPHND MV AK MV MAG C.P.R. XNATNX PD GUN MBKL I OLKA GLDAGA KQB FTQO SKMX GPDH NW LX SULMY ILLE MKH BEALF MRSK UFHA AKTS.

At the end of a strenuous hour or two, the following facts were established:

I. The letter was written on a thin but tough paper which bore no resemblance to any paper found among the effects of Paul Alexis. The probability was thus increased that it was a letter received, and not written by him.

2. It was written by hand in a purplish ink, which, again, was not like that used by, Alexis. The additional inference was drawn that the writer either possessed no typewriter or was afraid that his typewriter might be traced.

3. It was not written in wheel-cipher, or in any cipher which involved the regular substitution of one letter of the alphabet for another.

‘At any rate,’ said Wimsey, cheerfully, ‘we have plenty of material to work on. This isn’t one of those brief, snappy “Put goods on sundial’ messages which leave you wondering whether E really is or is not the most frequently recurring letter in the English language. If you ask me, it’s either one of those devilish codes founded on a book — in which case it must be one of the books in the dead man’s possession, and we only have to go through them — or it’s a different kind of code altogether — the kind I was thinking about last night, when we saw those marked words in the dictionary.’

‘What kind’s that, my lord?’.

‘It’s a good code,’ said Wimsey, ‘and pretty baffling if you don’t know the key-word. It was used during the War. I used it myself, as a matter of fact, during a brief interval of detecting under a German alias: But it isn’t the exclusive property of the War Office. In fact, I met it not so long ago in a detective story. It’s just-’

He paused, and the policemen waited expectantly.

‘I was going to say, its just the thing an amateur English plotter might readily get hold of and cotton on to. It’s not obvious, but it’s accessible and very simple to work. It’s the kind of thing that young Alexis could easily learn to encode and decode; it doesn’t want a lot of bulky apparatus; and it uses practically the same number of letters as the original message, so that it’s highly suitable for long epistles of this kind.’

‘How’s it worked?’ asked Glaisher.

‘Very prettily. You choose a key-word of six letters or more, none of which recurs. Such as, for example, SQUANDER, which was on Alexis’ list. Then you make a diagram of five squares each way and write the key-word in the squares like this:

S

Q

U

A

N

D

E

R

Then you fill up the remaining spaces with the rest of the.alphabet in order, leaving out the ones you’ve already got.’

‘You, can’t put twenty-six letters into twenty-five spaces,’ objected Glaisher.

‘No; so you pretend you’re an ancient Roman or’ a medieval monk and treat I and J as one letter. So you get this.’

S

Q

U

A

N

D

E

R

B

C

F

G

H

IJ

K

L

M

O

P

T

V

W

X

Y

Z

Now, let’s take a message What shall me say? “All is known, fly at once”—that classic hardy perennial. We write it down all of a piece and break it into groups of two letters, reading from left to right. It won’t do to have two of the same letters coming together, so where that happens we shove-in Q or Z or something which won’t confuse the reader. So now our message runs AL QL IS KN O W NF LYAT ON CE.’

‘Suppose there was an odd letter at the end?’

‘Well, then we’d add on another Q or Z or something to square it up. Now, we take our first group, AL We see that they come at the corners of a rectangle in which the other corners are SP. So we put down SP for the first two letters of the coded message. In the same way QL becomes SM and ISbecomes FA.’

‘Ah!’ cried Glaisher, ‘but here’s KN. They, both come on the same vertical line. What happens, then?’

‘You take the letter next below each — TC. Next comes OW, which you can do for yourself by taking the corners of the square.’

‘MX?’

‘MX it is. Go on.’

‘SK,’ said Glaisher, happily taking diagonals from corner to corner, PV, NP, UT

‘No, TU. If your first diagonal went from bottom to top, you must take it the same way again. ON=TU, NO would be UT.’

‘Of course, of course. TU. Hullo!’’ ‘What’s the matter?’

‘CE come on the same horizontal line.’

‘In that case you take the next letter to the right of each.’

‘But there isn’t a letter to the right of C.’

‘Then start again at the begining of the. Line’

This confused the Superintendent for a moment, but he finally produced DR