bells, trumpets, torches, gunshots, and the like. But to proceed with our business. When you prepare to write, you must reduce the interior epistle to this bi-literal alphabet. Let the interior epistle be:
| Fly. | ||
| Example of reduction. | ||
| F | L | Y |
| aabab | ababa | babba |
"Have by you at the same time another alphabet in two forms; I mean in which each of the letters of the common alphabet, both capitals and small, are exhibited in two different forms,—any forms that you find convenient."
[For instance, Roman and Italic letters; "a" representing Roman and "b" representing Italic.]
"Then take your interior epistle, reduced to the bi-literal shape, and adapt it, letter by letter, to your exterior epistle in the biform character; and then write it out. Let the exterior epistle be.
| "Do not go till I come." | ||
| Example of reduction | ||
| F | L | Y |
| aabab | ababa | babba |
| DONOT | GOTIL | LICOM—E |
| do not | go till | I come |
From the above given dates it would almost seem as if Bacon had treated the matter in a purely academic manner, and had drawn out of his remembrance of his younger days a method of secret communication which had not seen any practical service. Spedding mentions in his book "Francis Bacon and his Times" that Bacon may have got the hint of the 'bi-literal cypher' from the work of John Baptist Porta, "De occultis literarum notis," re-
