Page:The Mystery of the Sea.djvu/472

458 requiritur Conditio, aut Restrictio. Id hoc modo fiet. Primo, universae literae Alphabeti in duas tantummodo Literas soluantur, per Transpositionem earum. Nam Transpositis duarum Literarum, per Locos quinque, Differentiis triginta duabus, multo magis viginti quatuor (qui est Numerus Alphabeti apud nos) sufficiet. Huius Alphabeti. Exemplum tale est."

"But for avoiding suspicion altogether, I will add another contrivance, which I devised myself when I was at Paris in my early youth, and which I still think worthy of preservation. For it has the perfection of a cipher, which is to make anything signifying anything; subject however to this condition, that the infolding writing shall contain at least five times as many letters as the writing infolded; no other condition or restriction is required. The way to do it is this: First let all the letters of the Alphabet be resolved into transpositions of two letters only. For the transposition of two letters through five places will yield thirty-two differences; much more twenty-four, which is the number of letters in our Alphabet. Here is an example of such an Alphabet.

"Nor is it a slight thing which is thus by the way effected. For heare we see how thoughts may be communicated at any distance of place by means of any objects perceptible either to the eye or ear, provided only that those objects are capable of two differences; as by