CHAPTER XXIII

CREWE went to the table and picked up the plan.

"My first impression was that the circle of figures represented

some form of letters of the alphabet arranged on what is called the

cardboard or trellis cipher, in which a message is concealed by

altering the places of the letters without changing their powers. Such

messages are generally written after the Chinese fashion--upwards and

downwards--but there is no reason why a circle should not be used to

conceal the message. In this case I did not expect to find a message

hidden in the circle, but rather, the key to the solution of the

letters above the circle, which, I was convinced, formed the real

cryptogram.

"The recurring T's and M's in the top line seemed to indicate that it

was some form of changed letter cipher, complicated by having to be

read in connection with the figures in the circle, which represented

other letters of the alphabet. The numbers, representing an ascending

series from 6 to 89, with one recurring 6, suggested the possibility

of this form of cryptogram having been used. The numbers in the

centre suggested a sum, which, when done, would throw some light on

the arithmetical puzzle in the centre of the circle by division,

subtraction, or multiplication.

"I worked for a solution on these lines for some time, but ultimately

came to the conclusion that the solution did not lie within them. I am

not an arithmetician, but my calculations told me enough to make me

realize that I was on the wrong track.

"I next attempted to ascertain if the two mysterious messages--the

lines on the top and the circle of figures--were two separate messages

read independently of one another. I did not think they were, but I

determined to put it to the test. Obviously, if they were, the top

line was merely a changed letter cipher, and nothing more. These are

usually easy to decipher because of the frequency with which certain

letters recur. In English the letter that occurs oftenest is E, then T,

then A, O, N, I, then R, S, H; the others in lessening frequency down

to J and Z, which are the least used letters in the English alphabet.

The recurring letters in our cryptogram are T's and M's. Using these

as a basis to give me the key, I tried all likely combinations on the

changed letter basis, but without success.

"I came back to my original idea that the figures in the circle

were the solvent of the line of letters above, and concentrated my

efforts in attempting to discover their meaning. I finally came to the

conclusion that the figures represented the pages or lines of some

book."

"Like the cryptograms I used to solve when I was at school," suggested

Marsland, with a smile.

"Rather more difficult than that. In that form of cryptogram rows of

figures are turned into words once you hit on the right book. This

cryptogram is much more ingenious, for it consists of three parts--a

line of meaningless letters and a circle of equally meaningless

figures, with other figures within it, and some plain English verses

of Scripture, the whole probably interdependent. If the circle of

figures represented some book necessary to the solution of the whole

cryptogram, the first thing to find out was the book from which the

figures had been taken. I had not much difficulty in arriving at the

conclusion that this book was a large brass-bound family Bible I saw at

Cliff Farm."

"I suppose the texts on the bottom of the sheet suggested that idea to

you?" said Marsland.

Crewe shook his head.

"I've learnt to mistrust guesswork," he said. "It would be a jump at

random to come to the conclusion that the cryptogram had been drawn

on the fly-leaf of a Bible because it contained some Scripture texts.

There is no connection between the facts. In fact, it seemed unlikely

to me at first that a religious man like the old farmer would have

mutilated his family Bible for such a purpose. I was inclined to the

view that he had taken a fly-leaf from one of his _Leisure Hour_ bound

volumes, which at the farm range from 1860 to the early seventies--a

period of years when this kind of glossy thick paper was much used for

fly-leaves by English printers. But while I was examining the sheet

through the magnifying glass I detected this mark on the edge, which

proved conclusively to me that the cryptogram had been drawn on the

fly-leaf of the family Bible. Have a look at it through the glass--you

cannot detect it with the naked eye."

Crewe held the sheet edgeways as he spoke, and pointed to one of the

outer corners. Marsland gazed intently through the glass, and was able

to detect a minute glittering spot not much larger than a pin's point.

"I see it," he said, relinquishing the glass. "But I do not understand

what it means."

"It is Dutch metal or gold-leaf. The book from which this sheet was

cut was gilt-edged. That disposes of the volumes of _Leisure Hour_

and other bound periodicals, none of which is gilt-edged. When I was

looking at the books at the farm I noticed only two with gilt-edged

leaves. One was the big family Bible, and the other was a large, old

fashioned _Language of Flowers_. But this sheet could not have been cut

from _The Language of Flowers_."

"Why not?"

"Because it has two rounded corners. As a rule, only sacred books and

poetry are bound with rounded corners. In any case, I remember that

_The Language of Flowers_ at the farm is square-edged. Therefore the

sheet on which the cryptogram has been drawn was cut from the Bible.

"The next question that faced me was how the numbers had been used:

they did not represent the numbers of the pages, I was sure of that.

The Bible is a book in which figures are used freely in the arrangement

of the contents. The pages are numbered, the chapters are divided

into verses which are numbered, and there is a numbered table of

contents at the beginning of each chapter. Obviously, the Bible is

an excellent book from which to devise a cryptogram of numbers owing

to the multiplicity of figures used in it and the variety of ways in

which they are arranged. I found both a Bible and Prayer Book in the

bookshelves, here, and set to work to study the numerical arrangement

of the chapters, the divisions of the verses, and the arrangement of

figures at the head of the chapters."

"It was while I was thus engaged that I remembered that at the

beginning of the authorised version of the Bible is inserted a table

of the books of the Old and New Testaments, the pages on which they

begin, and the number of chapters in each. Here was the possibility

of a starting-point, sufficiently unusual to make a good concealment,

yet not too remote. I turned to the table, and, on running my eye down

it, I saw that the Psalms, and the Psalms alone, contain 150 chapters.

Now, the first line of central figures in the cryptogram is 150. I was

really fortunate in starting off with this discovery, because otherwise

I might have been led off the track by the doubling and trebling of the

3 in the second line of central figures, and have wasted time trying

to fathom some mystic interpretation of the 9--a numeral which has

always had a special significance for humanity: the Nine Muses, the

Nine Worthies, 'dressed up to the nines,' and so on. But with 150 as

the indication that the cryptogram had been composed from the Book of

Psalms, it was obvious that the next line of numerals in the centre

directed attention to some particular portion of them. As there are not

396 verses in any chapter of the Psalms----"

"Just what I was going to point out," broke in Marsland.

"Quite so. But it was possible that 396 meant Psalm 39, 6. Therefore I

turned to the thirty-ninth Psalm. Verse six of that Psalm reads:

"'Surely every man walketh in a vain shew: surely they are disquieted

in vain: he heapeth up riches, and knoweth not who shall gather.'"

"Appropriate enough," commented Marsland.

"There remained the final 6, under the 396, to be explained, before

I was able to start on the table which had been used to build up the

cryptogram. The fact that the figures in the outside circle start at

6 indicated that there was some connection between it and the inner

6. I came to the conclusion that the inner 6 meant one of two things:

either the designer preferred to start from the number 6 because he

thought the figure 1 was too clear an indication of the commencement

of his cryptogram, or else he made his start from the sixth letter of

the text. I thought the former the likelier solution, but I tried them

both, to make sure. The first five figures on the latter solution gave

me a recurring Y, which indicated that I was on the wrong track because

it was essential there should be no recurring letters. There are no

recurring letters in the other key, as the table shows:

6 7 8 9 10 11 12 13 14 15 16 17 18 19

S u r e l y e v e r y m a n

1 2 3 4 5 6 7 8 9 10 11 12 13 14

20 21 22 23 24 25 26 27 28 29 30 31 32 33

w a l k e t h i n a v a i n

15 16 17 18 19 20 21 22 23 24 25 26 27 28

34 35 36 37 38 39 40 41 42 43 44 45 46 47

s h e w: s u r e l y t h e y

29 30 31 32 33 34 35 36 37 38 39 40 41 42

48 49 50 51 52 53 54 55 56 57 58 59 60 61 62

a r e d i s q u i e t e d i n

43 44 45 46 47 48 49 50 51 52 53 54 55 56 57

63 64 65 66 67 68 69 70 71 72 73 74 75

v a i n: h e h e a p e t h

58 59 60 61 62 63 64 65 66 67 68 69 70

76 77 78 79 80 81 82 83 84 85 86

u p r i c h e s a n d

71 72 73 74 75 76 77 78 79 80 81

87 88 89 90 91 92 93 94 95 96 97 98 99

k n o w e t h n o t w h o

82 83 84 85 86 87 88 89 90 91 92 93 94

100 101 102 103 104 105 106 107 108 109 110

s h a l l g a t h e r

95 96 97 98 99 100 101 102 103 104 105

"The circle of figures taken in their ascending order and starting with

the second six, run thus:

6, 8, 9, 10, 11, 13, 17, 19, 20, 21, 23, 25, 26, 27, 39, 51, 54,

72, 80, 89.

Now, assuming that my interpretation of the solitary six in the circle

is correct--that the old man started from six because he thought the

use of the figure one gave away too much--we will substitute for these

figures the letters which appear underneath them in the table. The

substitution gives us the following row of letters:

S R E L Y V M N W A K T H I U D Q P C O S

"This is the line of letters from which we will endeavour to

reconstruct the old man's cryptogram. We can, I think, go forward

with the assurance that they are the actual letters represented by

the cryptogram, for several reasons. There are no recurring letters,

and they represent every letter in the text in consecutive order,

with three exceptions which are capable of a simple explanation. The

U has been taken from the second 'surely' instead of the first, to

mislead the solver. Otherwise you would have surely for the first

five numbers, which would be too clear an indication. The same reason

exists for making A the tenth letter instead of the eighth; which would

reveal the word 'man.' The final letter--the 'G' in 'gather'--has been

excluded, for a reason which I will presently explain."

"What about the second S--the final letter? Do you not call that a

recurring letter?" asked Marsland, who was closely examining the table

the detective had prepared.

"Not in the cryptographic sense. It is the first letter of the text

repeated after the line had been completed without recurring letters.

There is a special reason for its use. The old man has worked on what

is called the keyword cipher, which is the most difficult of all

ciphers to discover. This system consists of various arrangements,

more or less elaborate, of tables of letters, set down in the form of

the multiplication table, and from the table agreed upon messages are

constructed whose solution depends on the use of some preconcerted

keyword. The most scientific adaptation of this principle was

constructed by Admiral Sir Francis Beaufort. In his system the letters

of the alphabet are set down one under another from A to Z, then A is

added to the line. The next line starts with B and runs to another B at

the bottom. You continue till you have the whole alphabet set down in

this fashion. From this table and an agreed keyword, which may consist

of a proper name or a sentence of several words, you construct a cipher

message."

"How?" asked Marsland, in a tone of keen interest.

"That is what I now propose to demonstrate to you, if, as I think, the

old man constructed his cryptogram in accordance with this principle.

I have come to the conclusion that he modified and adapted this system

to his own ends, using the letters of the text from the Bible to

conceal it better, and then made it more difficult still by turning the

letters into figures after the manner I have described. He has also

made a slight but not uncommon variation from the Beaufort principle

by striking out the 'G' in 'gather,' which would follow the 'O' if

every letter in the text was used once, and substituting the final S,

instead of placing the 'S' after 'G.' But the clue that suggested to my

mind that he had worked on this principle are the two figures 6 coming

together at the top of the circle. In the substituted letters they

form two S's. Now, why does he have two S's when he carefully avoids

recurring letters in the rest of the table? And why did he insert the

first S again, as represented by the figure 6, instead of taking the

next S in this table?

"In pondering over these points I discovered, as I believe, the system

of cryptogram he used to construct his secret. He wanted to make the

cryptogram difficult of solution, but at the same time he wanted to

give some indication of the form of cryptogram he was using when his

heirs came to search for the money. The recurring S indicates that

he was working on a modification of the system I have explained, in

which you add the first letter of your first column to the bottom, and

continue on that system throughout the table. It is not much of a hint,

because we have got to find the keyword before we can use the table,

but by its help we will start with the assumption that the old man

worked on the following table:

S R E L Y V M N W A K T H I U D Q P C O S

R E L Y V M N W A K T H I U D Q P C O S R

E L Y V M N W A K T H I U D Q P C O S R E

L Y V M N W A K T H I U D Q P C O S R E L

Y V M N W A K T H I U D Q P C O S R E L Y

V M N W A K T H I U D Q P C O S R E L Y V

M N W A K T H I U D Q P C O S R E L Y V M

N W A K T H I U D Q P C O S R E L Y V M N

W A K T H I U D Q P C O S R E L Y V M N W

A K T H I U D Q P C O S R E L Y V M N W A

K T H I U D Q P C O S R E L Y V M N W A K

T H I U D Q P C O S R E L Y V M N W A K T

H I U D Q P C O S R E L Y V M N W A K T H

I U D Q P C O S R E L Y V M N W A K T H I

U D Q P C O S R E L Y V M N W A K T H I U

D Q P C O S R E L Y V M N W A K T H I U D

Q P C O S R E L Y V M N W A K T H I U D Q

P C O S R E L Y V M N W A K T H I U D Q P

C O S R E L Y V M N W A K T H I U D Q P C

O S R E L Y V M N W A K T H I U D Q P C O

S R E L Y V M N W A K T H I U D Q P C O S

"It is from this table, unless I am very much mistaken, that he

constructed the cipher at the top of the sheet," said Crewe.

Marsland examined the curious table of letters, with close scrutiny,

from various points of view, finally reversing it and examining it

upside-down. He returned it to Crewe with a disappointed shake of his

head.

"I can make nothing of it," he said.

"It is necessary for us to discover the keyword he worked on before

we can make use of it," said Crewe. "Once we get the keyword, we will

have no trouble in deciphering the mysterious message. The keyword is

the real difficulty in ciphers of this kind. It is like the keyword

of a combination lock. Without it, you cannot unlock the cipher. It

is absolutely insoluble. Suppose, for example, he had picked a word

at random out of the dictionary, and died without divulging it to

anybody, we should have to go through the dictionary word for word,

working the table on each word, till we came to the right one."

"But that would take years," exclaimed Marsland blankly.

"Unless we hit on it by a lucky accident. That is why the keyword

cipher is practically insoluble without knowledge of the keyword. It is

not even necessary to have a word. A prearranged code of letters will

do, known only to the composer of the cryptogram. If he wanted anybody

else to decipher his cryptogram, he would have to divulge to him not

only the form of table he worked on but the code of letters forming the

keyword."

"Well, I do not see we are much further forward," said Marsland

despondently. "Of course, it's very clever of you to have found out

what you have, but we are helpless without the keyword. The old man is

not likely to have divulged it to anybody."

"You are wrong," said Crewe. "He has divulged it."

"To whom?"

"To this paper. As I said before, he did not want his cryptogram to be

insoluble; he wanted his heirs to have his money, but he did not want

it found very easily. You have forgotten the texts at the bottom of

the paper. They have not been placed there for nothing. The keyword is

hidden in them."

"I forgot all about the texts--I was so interested in your

reconstruction of the cryptogram," said Marsland. "As you say, he

didn't put the texts there for nothing, so it seems likely that he has

hidden the keyword in them. But even now we may have some difficulty

in finding it. Do you propose to take the texts word for word, testing

each with the table, till you find the right one?"

"That would take a long while," said Crewe. "I hope to simplify the

process considerably. In fact, I think I have already discovered the

keyword."

"You have!" exclaimed Marsland, in astonishment. "How have you managed

that?"

"By deduction from the facts in front of us--or perhaps I should say

by reflecting on the hints placed in the texts. Isn't there something

about those texts that strikes you as peculiar?"

Marsland examined them attentively for some time, and shook his head.

"I'm afraid I'm not sufficiently well up in the Scriptures to notice

anything peculiar about them. I should say they were from the Old

Testament, but I couldn't tell you what part of it."

"The texts are from the Old Testament, from Jeremiah XXV and Isaiah

VII. They are remarkable for the fact that they represent two

passages--the only two instances in the whole Bible--where the writers

used cryptograms to hide their actual meaning. In the first instance

the prophet, Jeremiah, living in dangerous times, veils his attack

on the King of Babylon by writing Sheshak for Babel--Babylon; that

is, instead of using B B L, the second and twelfth letters of the

Hebrew alphabet, from the beginning, he wrote Sh Sh K from the end--a

simple form of cryptogram which is frequently used, even now. In the

second instance the prophet Isaiah, working on a very similar form of

cryptogram, writes 'Tabeal' for 'Remaliah.'

"Now, we are faced by two facts concerning the presence of these two

texts on the paper containing the cryptogram. In the first place, the

cryptogram was complete without the texts; for what purpose, then,

could they have been at the bottom of the sheet except to give a clue

to the discovery of that keyword without which no recovery of the

hidden treasure was possible, unless it was found by a lucky chance?

In the second place, the selection by the old man of the only two

cryptographic texts in the Bible was certainly not chance, but part

of a deliberate harmonious design to guide the intelligent searcher

to the right keyword. He was evidently versed in cryptography,

constructed this one as carefully as a mechanic putting together a

piece of mechanism, fitting all the parts carefully into one another.

The figures in the centre of the circle give the key to the outside

figures: the outside figures are the key to the cryptographic table

of letters from which the cryptogram is to be solved; there remains

the key to be found. It is not likely that the composer of such an

ingenious cryptogram would leave the keyword to guesswork.

"The whole thing is a Bible cryptogram from first to last: figures,

letters, words, and texts. It is even drawn on a sheet cut from

the Bible. Why? Such an act might be deemed irreverent in a deeply

religious man like the old man was, but when we piece the thing

together we find that he was actuated by a religious spirit throughout.

Not the least skilful part of his cryptogram is his concealment of

the keyword in the text at the bottom. The text would convey nothing

to most people, for very few people know anything about cryptograms,

still fewer people would know that these texts contain the only two

cryptograms in the Bible. Therefore, in accordance with his harmonious

design, it seems to me that the keyword should be found in the five

alternatives of the cryptic texts: Babel, Babylon, Sheshak, Remaliah,

or Tabeal.

"Babel and Babylon may be discarded because there is no letter B in the

cryptographic table, and it is essential that the keyword shall contain

no letter which doesn't also appear in the table. 'Sheshak' may also

be discarded for the present as unlikely because of the awkwardness

of the recurring 'Sh' in a keyword. There remain Tabeal and Remaliah.

The tendency of the composer would be to use the longer word, because

a long keyword is the better for the purpose. I think, therefore, we

should first try whether Remaliah is the keyword we are in search of."

"By Jove, Crewe, that is cleverly reasoned out!" exclaimed Marsland,

in some excitement. "Let's put it to the test. How do we apply this

keyword to the table?"

"Easily enough. On this sheet of paper we will write down the

cryptogram; and the keyword underneath it, letter for letter, thus:

T Y N M V R T T H S M

R E M A L I A H R E M

"Now, the first word of the cryptogram is T. Look in the first column

of the table for it, and then run your eye across the table for the

first letter of the keyword. When you have found it, look at the top of

the column and tell me the letter."

"K," said Marsland.

"Very well, then. We put down 'K' as the first word of the solution

and proceed in like manner through the whole of the cipher. The second

letter is Y--find it in the table, then look across for the second

letter of the key E, and then to the top of the column. What letter

have you?"

"C," said Marsland.

"KC, then, are the first two letters of our solution, and we go on to

the third, always repeating the same process. N in the first column, M

across, and the top gives you?"

"O," said Marsland.

"The next letter is M in the cryptogram and A in the keyword. What does

the top of the column give you?"

"L," replied Marsland. "But I say, Crewe, do you think we are on the

right track? K, C, O, L, is a queer start for a word isn't it? I know

of no word commencing like that."

"I may be mistaken, but I do not think so," replied Crewe firmly. "Let

us keep on till we've finished it, at all events."

They resumed their task, and ultimately brought out the letters: K, C,

O, L, C, H, C, R, A, E, S. Marsland gazed at the result in dismay.

"By Jove, we're on the wrong track," he said ruefully. "It is the wrong

word, Crewe. These letters mean nothing; you'll have to try again."

But Crewe did not reply. He was examining the result of his night's

labours closely. Suddenly he put down the paper with an unusual light

in his eye.

"No," he said. "I am right, the old man was thorough to the last

detail. He has given another clue to his heirs in the circle and the

two lines. They represent a clock face. But the figures round them run

the reverse way to clock figures. The cryptogram reads backwards. Hold

it up to that mirror, and see."

Marsland did so, and laid down the paper with a look of bewilderment.

"Search clock! The old grandfather clock at Cliff Farm!" he said.

The Mystery of the Downs · 第 23 / 26 章