But you know there is nothing which fascinates me like a mystery. Though I might try to keep my mind off the puzzle, the mind spins its own web on the borders of sleep. That short line at the end of the figures, “In 1739,” with the first words, “Left Bank,” drew around themselves all sorts of memories about the left bank of the Seine in the thirties of the eighteenth century. I thought of the Hotel Biron, finished in 1730; but its street number is not 27B. Then in 1735 was built that little hunting lodge in the Ruelle des Gobelins. The year “1739” had a gruesome association, for that was the birth year of Charles Henri Sanson, the executioner under the Terror — though he belonged to another quarter of Paris...
But my falling asleep did not end the events of that night. The window ledge of my room was not more than three feet from the flat roof of the garage. It was still dark when I was awakened by a slight sound outside my window.
I always know where my revolver is. In three seconds I was sending a shot — aiming low, for the legs — at a huge figure which had just risen to its feet at the far end of that roof. The man had climbed up from the garden wall — an athletic feat.
With a smothered cry he disappeared. I heard him drop on the other side of the wall; then after a moment I heard uneven running footsteps in the quiet street beyond. Hit, but not badly wounded!
Midnight marauders are no novelty in my life, but I wondered if there was some link between this one and the Vorontsov puzzle.
I rushed downstairs to the telephone, called up the police, the Sûreté, made myself known to them, and reported the case.
“There’s a street lamp on the corner,” I said, “and I saw the broad face of a man, his huge bulk, the dark cap he wore. He made off limping in the direction of the railway track. If you catch him tonight, telephone me” (I gave the number) “and I will come down and identify him. Otherwise it will have to wait two or three days, until I come back from Nice. Please give my regards to Inspector Lagrange and the chief.”
I spent the rest of the night on the lionskin couch in the studio, to be near the telephone. The servants had awakened at the sound of the shot, but I reassured them and sent them back to bed.
The police did not report a capture that night, but the next morning François and I found bloodstains on the garden wall. I told the butler that some thief had probably read in the newspaper of the family’s absence in the south, and was after the silver.
I was not sure of it myself. Until I knew what the cryptograph meant, I was keeping an open mind. The face I had seen in the light of the street lamp was decidedly Russian...
My meeting with Boris in Nice was affecting. He had been deeply attached to his grandmother.
When I showed him the “key,” his face went white.
“But I know nothing about it — nothing,” he gasped.
We were sitting in my bedroom in the hotel.
“And the princess never taught you a cipher,” I asked, “never talked about one? Neither she nor your father?”
“Never anything definite. But she was always interested in mysteries — after she met you. Five or six years ago, when you told us about the Rigaud case and the secret writing, you remember how keen she was. This paper is in her handwriting. Of course it may be a copy, but if so, who has the original? And how did it come to be hidden in my father’s portrait?”
I got up and walked the floor, thinking. Boris was watching me, and there was a glint of excitement behind the grief in his eyes.
I stopped beside his chair, and looked down at him,
“Some secret of great importance may be hidden here,” I said. “That is probably what she intended to tell you, on her return to Paris. Perhaps she had come to question the gypsy’s prophecy that she would live to be ninety-eight.”
The quick tears filled his eyes — spilled over.
“But I never could read it, Dexter — never in a thousand years.”
“I’m sure that you couldn’t. And I’m sure now that she meant me to help you with this, when she said, ‘Tell Dexter Drake.’ If she had time, if she could have controlled her speech, she would doubtless have told you all the details of whatever secret is hidden here. I feel that she laid a charge upon me, with her dying breath.”
The dear boy asked me to read the cipher — as if it had been a sheet of music! He had always believed I could do anything.
I sat down again, and took the paper from his hand. Then for the first time I examined it closely.
The highest number, 36, and the lowest, 3, proved that the letter significators do not go straight from 1 to 26, the number of letters in the English alphabet. There was a definite system of skipping, therefore. “Left Bank — in 1739” pointed clearly enough to the English language.
“As you see,” I said, “there is no division between the words. That makes it immensely more difficult to read.”
And if this was a secret writing which the princess had made herself, she was clever enough to avoid the obvious. She would never copy a ready-made cryptogram. I believed from the first that the very ingenious creation was hers.
There were sixty-seven numbers in all. I made a little table which showed that there were eighteen different numbers used.
Boris had been watching me in silence, nervously pulling at his little golden mustache. Suddenly he leaned forward:
“Dexter! Do you think — you know my father was very close to the czar. Though this paper is in Grandmamma’s writing, I wonder—”
The same question had occurred to me. But I told myself that when I had read the paper, when I knew what the princess wanted me to do, I could judge for myself whether I would go on with it.
Let me tell you briefly — for the reading of ciphers is a fine art — how I confidently started on my labors. I made another table, which showed the number of times each symbol was used.
You know, of course, that the letter “e” and the word “the” appear oftener than any others, in English. As the figure “5” appeared oftenest, eight times, was it “e”? Of the seven three-number combinations ending in 5, two were alike — 35-26-5. Ah! Had I found the word “the”? Once also, 5 was doubled as “e” is constantly doubled, in such words as “free,” and “street.” But when I glanced at the first five numbers, 5-35-26-5-18 — oh, if 35-26-5 was “the,” then the writing began with “Ethe—,” which was only possible if the opening word was “ether” or some of its derivatives and if 18 was “r.” It took me some time to prove that 18 could not be “r,” and also that 5 did not behave elsewhere like “e.” Neither did 9, which appeared seven times, nor 26, which appeared six times.
“Well, well!” I exclaimed.
After an hour I had convinced myself that the word “the” did not appear in that writing at all, and that even the letter “e” must be well down on the list.
Then I knew — I knew that infinite care and labor had been expended upon this cipher, that the very words composing the message had been deliberately chosen by one who knew how to avoid the obvious frequencies of the letters.