Night writing

A student at the school, Louis Braille, used the tools and Barbier's idea of communicating with raised dots in a form of code, and developed a more compact and flexible system for communications, Braille.

Function

The principle of night writing is to transcribe using 36 distinct phonetic sounds, each represented by a raised pattern of dots in a 2 × 6 grid.

The 36 sounds are represented in a 6 × 6 table; the 2 × 6 grid of dots designates the coordinates of the desired sound. For example, the sound placed in the first line and the third column of the table is represented by (1, 3). This, in turn, is written with 1 dot in the first column, and 3 dots in the second.

The phoneme "t" is represented thus:

Charles Barbier also invented the tools to facilitate this form of writing with raised dots: a shelf ruler that had groups of 6 horizontal grooves. To transcribe their message, the writer uses a punch to pierce the paper, guided by the grooves of the ruler. A movable cursor helps guide the punch. The relief writing appears on the back of the paper; the writing is therefore reversed, hence one must write from right to left. By running their fingers across the front, the recipient of the message counts the number of dots in each row and deduces the nature of the corresponding sound.

This was an extraordinary advancement in its time. Previously, the only writing accessible to the blind was one developed by Valentin Haüy, the founder of the Royal Institution for Blind Youth. His system impressed the shapes of typographic characters onto wet paper. However, as the embossed letters had to each be distinct, books using the system were cumbersome and of limited length. Furthermore, students had no means to reproduce the method so as to write themselves.

Barbier's night writing also faced several limitations and imperfections:

• no combinations of dots existed to represent capital letters, musical notes, mathematical symbols, etc.
• the height of the grid (2 × 6 points) made it impossible to read in a single go with one finger
• potential information is wasted: a grid of 12 points would theoretically allow up to 2¹² (or 4096) symbols to be represented, when Barbier presented only 36 symbols.