1. The literal cipher. The most famous of all literal cryptograms is the famous biliteral cipher described by Sir Francis Bacon in his De Augmentis Scientiarum. Lord Bacon originated the system while still a young man residing in Paris. The biliteral cipher requires the use of two styles of type, one an ordinary face and the other specially cut. The differences between the two fonts are in many case so minute that it requires a powerful magnifying glass to detect them. Originally, the cipher messages were concealed only in the italicized words, sentences, or paragraphs, because the italic letters, being more ornate than the Roman letters, offered greater opportunity for concealing the slight but necessary variations. Sometimes the letters vary a trifle in size; at other times in thickness or in their ornamental flourishes. Later, Lord Bacon is believed to have had two Roman alphabets specially prepared in which the differences were so trivial that it is almost impossible for experts to distinguish them.

"For the Muse was not then Greedy of gain or mercenary; Nor were Terpsichore's sweet, Honey-toned, silvery soft-voiced Strains made merchandise of."...

These twelve letters, he designed, formed, combined, weighed, and changed, and created with them the twelve divisions of the heavens (namely, the...