the art of finding the alphabet of a cypher. See Cypher.

Every language has, besides the form of its characters, something peculiar in the place, order, combination, frequency, and number of the letters; to all which particular regard is to be had in deciphering. In all languages, however, the following rules ought to be observed: 1. One word is to be compared with another, that their resemblance and difference may be known. 2. No word can be without a vowel. 3. A word of one letter is always a vowel, or a consonant with an apostrophe. 4. The vowels recur much more frequently than the consonants. 5. Double vowels may be at the beginning of a word, but not double consonants. 6. Double characters at the beginning of a word are always vowels. 7. Short words of two or three letters have two or three, or one or two consonants. 8. The vowels are therefore most easily learned from the short words which are to be first considered by the decipherer. 9. If double characters are preceded by a single letter, the letter is a vowel. 10. In languages abounding with diphthongs one one vowel is of ten joined with another. II. The letter that precedes or follows double consonants is, if a consonant, always one of the liquids, l, m, n, r, s.

12. If two different characters occur, of which the latter is often conjoined with various letters, and the former is never found either by itself, or followed by any other letter, those two are qu. 13. These letters gu are always followed by a vowel. 14. One vowel recurs more frequently than another, as do the consonants, according to the language, &c.