“No!” he exclaimed. “It isn’t what I expected. Guess-work will never help you in this solution. You might try for a hundred years to decipher it, but will fail, if you do not discover the key. Indeed, so much ingenuity is shown in it that a writer in the last century estimated that in such a pack of cards as this, with such a cipher upon them, there are at least fully fifty-two millions of possible arrangements.”
“But how is the cipher written?” I inquired much interested, yet with heart-sinking at his inability to assist me.
“It is done in this way,” he said. “The writer of the secret settles what he wishes to record and he then arranges the thirty-two cards in what order he wishes. He then writes the first thirty-two letters of his message record, or whatever it may be, on the face or on the back of the thirty-two cards, one letter upon each card consecutively, commencing with the first column, and going on with columns two and three, working down each column, until he has written the last letter of the cipher. In the writing, however, certain prearranged letters are used in place of spaces, and sometimes the cipher is made still more difficult for a chance finder of the cards to decipher by the introduction of a specially arranged shuffle of the cards half-way through the writing of the record.”
“Very ingenious!” I remarked, utterly bewildered by the extraordinary complication of Burton Blair’s secret. “And yet the letters are so plainly written!”
“That’s just it,” he laughed. “To the eye it is the plainest of all ciphers, and yet one that is utterly unintelligible unless the exact formula in its writing be known. When that is ascertained the solution becomes easy. The cards are rearranged in the order in which they were written upon, and the record or message spelt off, one letter on each card in succession, reading down one column after another and omitting the letter arranged as spaces.”
“Ah!” I exclaimed fervently. “How I wish I knew the key.”
“Is this a very important secret, then?” asked Boyle.
“Very,” I replied. “A confidential matter which has been placed in my hands, and one which I am bound to solve.”
“I fear you will never do so unless the key is in existence,” was his answer. “It is far too difficult for me to attempt. The complications which are so simply effected in the writing, shield it effectually from any chance solution. Therefore, all endeavours to decipher it without knowledge of the pre-arrangement of the pack must necessarily prove futile.”
He replaced the cards in the envelope and handed them back to me, regretting that he could not render me assistance.