2009-07-14 15:15:00 UTC
I have little detailed knowledge of cryptography, but in my research I have
encountered a ciphered text that is of great historical interest and would
like some assistance or suggestions about how to go about decoding it. I'd be
very grateful for any help or pointers to other mailing lists, sources of
expertise, software, etc. One source of difficulty is that the plaintext, if
there is any, would be in old Spanish.
The text appears in a 1644 publication by Michael Florent van Langren titled
"La verdadana de longitude par mer y terra". In this, he claims to have
discovered a new, improved method to determine longitude more accurately than
before, a topic that was of major interest in all the courts of Europe. But,
so that no one would steal his method, he says he is describing it in code,
that he will reveal to his patron, King Phillip of Spain. Almost certainly,
the method concerns some variation on what is called the 'lunar method',
whereby time difference between two places can be determined by measuring
angles of lunar events and translating time difference into degrees longitude.
Decoding this text is the final puzzle piece in some historical research on
which I've been working for the last year. It is very important for me to
understand whether this was in fact the 'secret' he was guarding, or perhaps
just a ruse to make it look like he had discovered something new.
I've placed as fair a transcribed copy as I can at:
For context, and an image of the original manuscript portion, see:
Again, thanks in advance for any help with this.