Nyctography


Nyctography is a form of substitution cipher writing created by Lewis Carroll in 1891. It is written with a nyctograph and uses a system of dots and strokes all based on a dot placed in the upper left corner. Using the Nyctograph, one could quickly jot down ideas or notes without the aid of light. Carroll invented the Nyctograph and Nyctography as he was often awakened during the night with thoughts that needed to be written down at once, and didn't want to go through the lengthy process of lighting a lamp only to have to then extinguish it.

The nyctograph

The device consisted of a gridded card with sixteen square holes, each a quarter inch wide, and system of symbols representing an alphabet of Carroll's design, which could then be transcribed the following day.
He first named it "typhlograph" from , but at the suggestion of one of his brother-students, this was subsequently changed into "Nyctograph" from nyctos
Initially, Carroll used an oblong of card with an oblong cut out of the centre to guide his writing in the dark. This did not appear to be satisfactory as the results were illegible. The new and final version of the nyctograph is recorded in his journal of September 24, 1891, and is the subject of a letter to The Lady magazine of October 29, 1891:
From the description it appears that Carroll's nyctograph was a single row of 16 boxes cut from a piece of card. Carroll would enter one of his symbols in each box, then move the card down to the next line and then repeat the process.

Nyctographic alphabet

Each character had a large dot or circle in the upper-left corner. Beside the 26 letters of the alphabet, there were five additional characters for 'and', 'the', the corners of the letter 'f' to indicate that the following characters were digits, the corners of the letter 'l' to indicate that they were letters, and the corners of the letter 'd' to indicate that the following six characters were a date in DDMMYY format. There was no capitalization, punctuation or digits per se, though modern font designers have created them. Like in Braille, numbers were indicated by letters preceded by a digit character. The values were taken from his Memoria Technica, which assigned two consonants to each digit, with vowels unassigned, so that any number could be read off as a word.