It is to be noticed that Bacon in setting forth the cipher in its completeness directs attention to its infinite possibilities and variations. The organised repetition of any two symbols in combinations of not more than five for one or both symbols may convey ideas. Not letters only but colours, bells, cannon, or other sounds may be used with effect. All the senses may be employed, or any or some of them, in endless combinations.
Again it is to be noted that even in his first allusion to the system in 1605, he says, “to write Omnia per Omnia, which is undoubtedly possible, with a proportion Quintuple at most, of the writing infoulding, to the writing infoulded.”
“Quintuple at most!” But in the instances of his system which he gives eighteen years later, when probably his time for secret writing as a matter of business had ceased, and when from the lofty altitude of the Woolsack he could behold unmoved any who had concealments to make—provided of course that they were not connected with bribes—there is only one method given, that of five infolding letters for each one infolded. In the later and fuller period he speaks also of the one necessary condition “that the infoulding writing shall contain at least five times as many letters as the writing infoulded”—
Even in the example which he gives “Do not go till I come,” there is a superfluous letter,—the final “e;” as though he wished to mislead the reader by inference as well as by direct statement.
Is it possible that he stopped short in his completion of this marvellous cipher? Can we believe that he who openly spoke from the first of symbols “quintuple at most,” was content to use so large a number of infolding letters when he could possibly do with less? Why, the last condition of excellence in a cipher which he himself laid down, namely, that it should “bee without suspicion,” would be endangered by a larger number than was actually necessary. It is by repetition of symbols that the discovery of secret writing is made; and in a cipher where, manifestly, the eye or the ear or the touch or the taste must be guided by such, and so marked and prolonged, symbols, the chances of discovery are enormously increased. Doubtless, then, he did not rest in his investigation and invention until he had brought his cipher to its least dimensions; and it was for some other reason or purpose that he thus tried to divert the mind of the student from his earlier suggestion. It will probably be proved hereafter that more than one variant and reduction to lower dimensions of his biliteral cipher was used between himself and his friends. When the secrets of that “Scrivenry” which, according to Mr. W. G. Thorpe in his interesting volume, “The Hidden Lives of Shakespeare and Bacon,” Bacon kept at work in Twickenham Park, are made known, we shall doubtless know more on the subject. Of one point, however, we may rest assured, that Bacon did not go back in his pursuance of an interesting study; and the change from “Quintuple at most” of the infolding writing of 1605, to “Quintuple at least,” of 1623, was meant for some purpose of misleading or obscuration, rather than as a limitation of his original setting forth of the powers and possibilities of his great invention. It will some day be an interesting theme of speculation and study what use of his biliteral cipher had been made between 1605 and 1623; and what it was that he wished to conceal.
That the original cipher, as given, can be so reduced is manifest. Of the Quintuple biliteral there are thirty-two combinations. As in the Elizabethan alphabet, as Bacon himself points out, there were but twenty-four letters, certain possibilities of reduction at once unfold themselves, since at the very outset one entire fourth of the symbols are unused.