"A French message in an English envelope, inclosing an unmounted
photograph of Madeline Spencer, a well-known German Secret Agent in
Paris," Carpenter remarked slowly; "and the letter is borne by Madame
Durrand to the French Ambassador. You see, my intuition was right? the
letter is in French; and as it is of French authorship the key-word is
French. That narrows very materially our search. Find the key-word to
the Vigenerie cipher of the French Diplomatic Service and we shall have
the translation."
"You haven't that word?" Harleston asked.
"We've got quantities of keys to French ciphers, and numerous ones to
the Blocked-Out Square, but they won't translate this letter." He took
up a small book and opened it at a mark. "Here are samples of the
latter: _ecclesiastiques, coeur de roche, a deau eaux, fourreau, chateau
d'eau_, and so on. But, alas, none of them fits; the French Government
has a new key. Indeed, she changes it every month or oftener; sometimes
she changes it just for a single letter."
"Then we must apply ourselves to obtaining the French key-word,"
Harleston remarked. "Can you--do it?"
"Maybe we can pilfer it and maybe we can't. At least we can make a brisk
attempt. I will give orders at once.
Pages:
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155