Fig. 8.—The fractional cipher.

Adopting this method the word CIPHER therefore appears as in [Fig. 9]. As numerals above 5 do not appear in this cipher any more than does the figure 0, they can be added at will to complicate the appearance of the cryptogram, as shown in [Fig. 10], where the same word is shown with the addition of meaningless numerals.

124214
341353

Fig. 9.—The word
“cipher.”

102943281047
384016395639

Fig. 10.—Complicated
fractional cipher.

The Sphinx

Now to turn to more scientifically constructed ciphers, such as have been employed by various Governments in correspondence with their ambassadors and secret servants.

The Sphinx Cipher, shown in [Fig. 11], is based upon a key-word of six or seven letters, previously arranged by the parties concerned A key-alphabet is written in full at the top of the plan, and against each letter of the key-word a complete alphabet is written as shown in the figure.

ABCDEFGHIJKLMNOPQRSTUVWXYZ
Bbcdefghijklmnopqrstuvwxyza
Acdefghijklmnopqrstuvwxyzab
Ldefghijklmnopqrstuvwxyzabc
Fefghijklmnopqrstuvwxyzabcd
Ofghijklmnopqrstuvwxyzabcde
Ughijklmnopqrstuvwxyzabcdef
Rhijklmnopqrstuvwxyzabcdefg