Now this letter was written according to a preconcerted cypher. Every
third letter after a stop was to tell. In this way Sir John made
out--“Panel at east end of chapel slides.” On the following even, the
prisoner begged to be allowed to pass an hour of private devotion in the
chapel. By means of a bribe, this was accomplished. Before the hour had
expired, the chapel was empty--the bird had flown.
An excellent plan of indicating the _telling_ letter or word is through
the heading of the letter. “Sir,” would signify that every third letter
was to be taken; “Dear sir,” that every seventh; “My dear sir,” that every
ninth was to be selected. A system, very early adopted, was that of having
pierced cards, through the holes of which the communication was written.
The card was then removed, and the blank spaces filled up. As for example:
MY DEAR X.--[The] lines I now send you are forwarded by the kindness
of the [Bearer], who is a friend. [Is not] the message delivered yet
[to] my Brother? [Be] quick about it, for I have all along [trusted]
that you would act with discretion and despatch.--Yours ever,