agencies for the blind in Great Britain and the United States met in London and agreed upon a system known as Standard English Braille, grade 2. In 1957 Anglo-American experts again met in London to further improve the system.

In addition to the literary Braille code, there are other codes utilizing the Braille cell but with other meanings assigned to each configuration. The Nemeth Code of Braille Mathematics and Scientific Notation (1965) provides for Braille representation of the many special symbols used in advanced mathematical and technical material. There are also special Braille codes or modifications for musical notation, shorthand, and, of course, many of the more common languages of the world.

Writing Braille by hand is accomplished by means of a device called a slate that consists of twometal plates hinged together to permit a sheet of paper to be inserted between them. Some slates have a wooden base or guide board onto which the paper is clamped. The upper of the two metal plates, the guide plate, has cell-sized windows; under each of these, in the lower plate, are six slight pits in the Braille dot pattern. A stylus is used to press the paper against the pits to form the raised dots. A person using Braille writes from right to left; when the sheet is turned over, the dots face upward and are read from left to right.

Braille is also produced by special machines with six keys, one for each dot in the Braille cell. The first Braille writing machine, the Hall Braille writer,