"Simple!"

"Very. It's so simple that it's baffling."

"Do you mean to say you are going to be able to find a meaning in squares and crosses?"

"I--I don't believe it is going to be so very difficult to translate them."

"Great guns!" said the Captain. "Do you mean to say that you can ultimately translate that cipher?"

The Tracer smiled. "Let's examine it for repet.i.tions first. Here we have this symbol

[Ill.u.s.tration: Cryptographic symbol]

repeated five times. It's likely to be the letter E. I think--" His voice ceased; for a quarter of an hour he pored over the symbols, pencil in hand, checking off some, subst.i.tuting a letter here and there.

"No," he said; "the usual doesn't work in this case. It's an absurdly simple cipher. I have a notion that numbers play a part in it--you see where these crossed squares are bracketed--those must be numbers requiring two figures--"

He fell silent again, and for another quarter of an hour he remained motionless, immersed in the problem before him, Harren frowning at the paper over his shoulder.

CHAPTER X

"Come!" said the Tracer suddenly; "this won't do. There are too few symbols to give us a key; too few repet.i.tions to furnish us with any key basis. Come, Captain, let us use our intellects; let us talk it over with that paper lying there between us. It's a simple cipher--a childishly simple one if we use our wits. Now, sir, what I see repeated before us on this sheet of paper is merely one of the forms of a symbol known as Solomon's Seal. The symbol is, as we see, repeated a great many times. Every seal has been dotted or crossed on some one of the lines composing it; some seals are coupled with brackets and armatures."

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"What of it?" inquired Harren vacantly.

"Well, sir, in the first place, that symbol is supposed to represent the spiritual and material, as you know. What else do you know about it?"

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"Nothing. I bought a book about it, but made nothing of it."

"Isn't it supposed," asked Mr. Keen, "to contain within itself the nine numerals, 1, 2, 3, 4, 5, 6, 7, 8, 9, and even the zero symbol?"

"I believe so."

"_Ex_actly. Here's the seal

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Now I'll mark the one, two, and three by crossing the lines, like this:

one,

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two,

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three,

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Now, eliminating all lines not crossed there remains

the one,

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the two,

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the three,

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And here is the entire series:

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and the zero--"

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A sudden excitement stirred Harren; he leaned over the paper, gazing earnestly at the cipher; the Tracer rose and glanced around the room as though in search of something.

"Is there a telephone here?" he asked.

"For Heaven's sake, don't give this up just yet," exclaimed Harren.

"These things mean numbers; don't you see? Look at that!" pointing to a linked pair of seals,

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"That means the number nineteen! You can form it by using only the crossed lines of the seal.

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Don't you see, Mr. Keen?"

"Yes, Captain Harren, the cipher is, as you say, very plain; quite as easy to read as so much handwriting. That is why I wish to use your telephone--at once, if you please."