oment the queer box itself was forgotten in the wonderment over
the cipher. That it would prove a solution to the mystery, if such there
was, and that it was not a joke, was believed by all. Even Allen, calm
as he usually was, displayed some excitement. The girls themselves could
not conceal their eagerness.

"How are you going to make sense out of that?" asked Roy, who did not
like to spend much time over anything. "It's worse than Greek."

"Most ciphers are," agreed Allen. "The only way to translate it is to go
at it with some sort of system. I'll need plenty of paper, and some
pencils."

"I'll tell you what to do," said Mr. Nelson. "Make several copies of the
cipher, and we can all work on it at once. It will be a sort of game."

And a fascinating game it proved. The possibility that the queer paper
in the iron box might contain directions for finding some hidden
treasure made it all the more alluring.

"There are any number of ciphers," Allen explained, when several copies
had been made of the original. "The simplest is to change the letters of
the alphabet about, using Z for A, and so on. Another simple one is to
make figures stand for letters, as No. 1 is A, and so on. But those are
so simple that only a schoolboy would use them."

"What are same of the more difficult ciphers?" asked Betty.

"Well, there are so many I don't know that I could explain them all. But
the most simple of the difficult ones is the taking of a number of
arbitrary signs or symbols to represent the letters of the alphabet.
That is what was done in Poe's 'Gold Bug,' you remember. Unless the
person has a copy of the list of signs and symbols it is very difficult
to decipher that cipher, or decode it, as they say in government
circles."

"Ahem!" exclaimed Will, with an important air, as all eyes were turned
on him. "I ought to know something about that, but you see they haven't
trusted me with the code book yet. Now then, Allen, how are we to go
about this Chinese puzzle?"

"If I had that story of Poe's here, it would be rather easier," Allen
said. "As it is, we shall have to do a little preliminary work. To start
off with we will take the letter E."

"Why E?" asked Roy.

"Because of all the letters in the ordinary use of English, that letter
most frequently occurs," Allen answered. "In other words, if you take a
written, or printed, page, and count up the letters, you will find that
E is used most frequently."

"What is the nex