“It is an unknown cipher, without a doubt—even though you recognise the basis.”
“Numerical ciphers are always most difficult,” Griffin declared. “Yet was it not Edgar Allen Poe who declared that human ingenuity could not invent a cipher which human ingenuity could not solve. I have tried my calculations upon the earliest known text, that preserved in St. Petersburg—but in vain.”
“What do you think of the dead man’s statement that the key is divided into two parts—one portion being concealed in each city?”
“I don’t accept that as genuine,” declared the Professor. “I regard it as a mere embellishment of facts, in order to prevent any one from trying to unriddle the message. The unfortunate man ordered you to destroy the directions for reading the message, together with the statement itself.”
“I rather wish I had disobeyed,” remarked the Doctor with a grin. “The fact that it was in manuscript and not in typing shows that he would not trust any one with sight of it.”
“Which goes far to prove the truth of my argument. There is a key number, depend upon it. When once you have that, and we ascertain at what point to start, then the secret record will soon be revealed.”
“But how can we obtain it—that’s the question,” the Doctor said. “I would like to know how far the inquiries of our enemies have advanced. This copy was obtained from the complete copy in their possession.”
“Who are our enemies? Do you know them?” asked the Professor, starting forward quickly.
“No. My friend, though he had supplied me with this, refuses all information concerning them, except to say that they are both powerful and wealthy.”
“What do they know concerning the key?”