Page:Popular Science Monthly Volume 33.djvu/665

Rh been invented in which the writer traces with a pencil the characters of the usual alphabet, assisting his pencil by guides pierced with openings. In the German system of Hebold, the letters are written in squares that are notched in each side. In the English Moon tablet, which is composed of narrow strips of wood glued

 1. Fortress. 2. Go bang, 3 and 4. Pawns. 5. Chess. 6. Checkers. 7 and 8. White and black checker-pieces. 9 and 10. Needles for the blind (much magnified).

upon cloth, the strips serve as rulers, or guides, along the edge of which the line is written, each one being rolled up when the line is finished, to give place to the next strip at the proper interval for the next line. Pencil-writing has likewise been studied by Guldberg in Denmark, Galimberti in Italy, and Bourgougnon in France. Valentin Haüy devised a method of pencil-writing by placing the paper upon a frame, in the interior of which were stretched parallel cords of catgut; between these cords may be traced signs of corresponding height. In Duphan's instrument narrow strips of cardboard are pasted at equal distances upon a thicker sheet. The paper having been placed upon this widely furrowed tablet, the blind writer feels with the point of his pencil the edges of the strips that are in relief.

None of these systems, however, permit the blind man to revise what he has written. A writing in relief is what is wanted, which should be readable by seeing persons not initiated in the Braille system, and which the blind man too could trace and read with facility. Such a system is provided in the stylography which the Count de Beaufort has invented (Fig. 2, No, 8). The apparatus, or stylograph, is of the simplest character, and can be made at home by almost any one. Cover a sheet of paper with a piece of thick cotton cloth; stretch this sheet over a series of parallel horizontal wires or cords about four millimetres apart; place upon this tablet