The UnMuseum - The Beale Cryptograms: "somewhere six feet under the ground in Virginia is over $30 million in gold" ... just finished reading the brilliant "Code Book" and one of the more interesting passages was the bit about the possible treasure hidden by mr Beale.
The second of his "clues" was coded using the Declariation of independence - so perhaps the other to are simple variations on the same? Counting backwards? Or the number of vowels? Or adding one for every G in the text? ...would make sense not to have to many different papers - but still not use it straight forward (to insecure - a lot of money even now!)