Book Two

Ch. 6.

imaginary lines, each one consisting of eight, or, if you please, of twelve, or even more points, equal distances apart. On each side of this figure let numbers fill the outside points, in order to indicate not only in these outside rows themselves, but in other interior rows as well, the places which the letters that are to be scattered are to occupy. In illustration, let us have the following scheme:

1	.	.	.	.	.	.	3
5	.	.	.	.	.	.	7
6	.	.	.	.	.	.	8
2	.	.	.	.	.	.	4

The matter will be made clearer by an example. Let us take a secret and, if possible, restrict the number of its letters to some multiple of the number eight; e.g. thirty-two, as in the following sentence: Spinola hatt Oppenheimb einbekommen. Now, for example, scatter the first eight letters in the order in which we are bidden by the numbers; then arrange the following eight according to the same scheme, and continue in this way until you have filled all the points with letters. So at length will result the following block of letters:

s	a	h	b	k	i	t	i
o	p	b	m	e	i	e	a
l	p	e	m	n	n	n	h
p	t	e	e	o	m	o	n

But in the actual epistle which is to be written by this formula the practical cryptographer will so disarrange the above formation that, without holding to the number eight, he will write as many letters in each line as he can. For he who has understanding of this subject will easily reconstruct the formation given above, when the time comes for him to bring back the letters to the order that shall reveal the secret. Here belong two other processes, very similar in arrangement to the above process, and also rather more elegant. These are explained in Bk. 9.c.5., in the secret sense underlying the example there subjoined to my first Mode. If you wish, you may dig them out there. For I have not wished to divulge them without some effort on your part.