once acquired a knowledge of it can easily detect the form in which it is applied.
In "experiments" of second sight the "subject" is generally blindfolded, and placed at a distance from the operator, sometimes even in an adjoining room, but always within easy earshot; the operator receives from the audience the questions to which they desire answers, or the objects which they wish to be described; and he asks the subject, in apparently the most natural and meaningless words, for the required reply.
Those natural and meaningless words convey, with infallible exactness, the answer which it is necessary to give.
The first letters of the consecutive words in the operator's question stand for the required letters or figures; and the whole science of "double vue" consists in nothing more than a clever pre-arranged use of initial letters, which signify either numbers or other letters than themselves, according to the nature of the question.
Let us suppose, for instance, that the number 12 is asked for. The operator calls to the subject "Dites le nombre,"[1] or, to utterly destroy suspicion, he may even say to the questioner, "Demandez-le vous-même." In either case the subject would unhesitatingly and instantly answer "Twelve."
The following table will show how simply this is effected:
| 1 | is conveyed by the letter | D. |
| 2 | L. | |
| 3 | C. | |
| 4 | P. | |
| 5 | Q, or "Quel est." | |
| 6 | A, or "A present." | |
| 7 | F. | |
| 8 | V. | |
| 9 | N, | |
| 0 | M. |
In the example given above the first letters of the consecutive words, "Dites le nombre," and "Demandez-le vous-même," are D L, which, as the table shows, stand for 1 and 2, or 12.
It will, however, be at once observed that the question must be so arranged as not only to announce the figures themselves to the subject, but also to tell him how many of them there are; as, otherwise, he might suppose that every consecutive initial letter in a long question stood for a required figure. ‘This difficulty is got over by a very neat expedient.
When a single figure is asked for, the operator employs in his question the word "chiffre." If, for instance, a 9 be wanted, he would say, "Nommez le chiffre;" and the subject perceiving, from the use of "chiffre," that one figure was all he had to give, would at once name 9, which is the figure represented by N. If this guide were not before him he would give the equivalents of all the initial letters in the sentence, N, L, and C, and would say, 923.
The following table of questions shows how all the single figures may be conveyed:
1. Dites le chiffre.
- ↑ The key is given in French, as nearly all performances of second sight are carried on in that language; but it may of course be easily arranged in English.
