Chapter XXI

_A Lost Clue_

"Suppose we admit, for the sake of argument," began Betty "that John

Thaneford was in possession of the secret. Then everything points back

to his father, old Fielding, who certainly had all the brains of the

family. Last and most important, it was a secret which Mr. Thaneford,

senior, desired to impart to me; he did tell me all he could."

"The series of numbers, you mean? I recall them perfectly: 1-4-2-4-8.

And what then?"

"Do you remember the story of Christian and his fellow pilgrim, Hopeful,

imprisoned in Giant Despair's stronghold of Doubting Castle? After

languishing for a week or more in darkness and misery, Hopeful suddenly

bethinks him of a key which he has in his bosom, a key that will unlock

any door in the castle. The rest is easy.

"So, too, I had my key, but I had only used it once--to unlock the first

and most obvious door----"

"The combination of the safe," I interrupted.

"Precisely. It never occurred to either of us that it might be a

master-key to which all locks must yield. But so it was.

"Not that I learned to use it without a lot of trouble and

discouragement. It took months and months, and I only got it fully

working on the train trip down from Stockbridge.

"Of course, you have guessed that the whole story lay buried in that

leather-bound book belonging to Fielding Thaneford which we found in the

safe. I remembered all that you had told me about 'Le Chiffre

Indechiffrable,' but even granting that that particular cypher had been

employed, how was I ever to stumble upon the indispensable key-word, or

more likely, key-sentence?

"One day I had an inspiration. There was the series of numbers:

1-4-2-4-8. Considered as numbers merely they could be of no use, since

most cypher codes are built up on letters. But I might put the numbers

into their written word equivalents, thus: One-four-two-four-eight It

was certainly conceivable that these letters might form the

key-sentence; it would be all the more easily memorized since, in its

numerical form, it served as a combination to the safe.

"I had with me the magic square which you had made for me, and I began

very carefully to work out the problem according to your directions.

"The initial procedure was to put down my theoretical key-sentences,

thus:"

O N E F O U R T W O F O U R E I G H T

"Underneath I must write the cypher message, and half a dozen letters

would be enough to show if I were on the right track. I opened Mr.

Fielding Thaneford's old book, and copied down the first seven letters,

ranging them vertically under the key-letters. That gave me this

arrangement:"

O N E F O U R

Q W O T T U I

"Now the rule goes on to say that you must find the letter O in the top

horizontal column, and follow that column vertically downward until you

come to the first cypher letter, in this case Q. The letter at the

outside, left end of this second horizontal column, will be the first

letter of the original message.

"Well, I tried it, and got the letter B. The next pair yielded an I,

which was encouraging, as one would expect a vowel in this position. But

the third try gave me a J, and that was not so promising; then I got an

N and an E. So far my decoded message read: BIJNE; not very

enlightening. The next pair showed the letter U in both key-sentence and

cypher. Such a combination is impossible on our magic square, and I had

to put down a blank space. The final letter obtained was a Q, and the

complete result read: BIJNE-Q. Pure gibberish of course. I tried out a

few more pairs, and then gave up in disgust; my beautiful theory had

fallen to pieces.

"Just the same, I wasn't ready to give it up. I knew, right in my bones,

that old Mr. Thaneford had wanted to tell me something of supreme

importance at that last moment on his deathbed, when my hand lay in his

and I could feel the intermittent pressure of his fingers. It was

impossible that I should be mistaken about any of the figures, for he

went over the series three or four times; besides, they did open the

safe.

"I was still sure that the numbers meant something more than the mere

combination to an old strong-box that held nothing of any pecuniary

value. The real secret lay between the covers of that leather-bound

book, and I was certain that the old man had been desirous that I should

discover it. The Thanefords and the Hildebrands had not been friends for

a long while, although nobody knew just why. Probably, it was some

ancient grudge Or unforgiven wrong, and old Mr. Thaneford had done his