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The slate and stylus are tools used by blind persons to write text that they can read without assistance.〔Alpha Chi Omega (1908)〕〔Shrady, et al.(1902)〕 Invented by Charles Barbier as the tool for writing night writing,〔Note: Different references assign invention of the slate and stylus to either Barbier or Braille. However, Braille (1829) credits Barbier with the invention. Barbier's slate consisted of six slots; Braille reduced it to three, as his cells were only half the size of Barbier's. When dashes were removed, the slots were no longer needed in full and were replaced with pairs of dots.〕 the slate and stylus allow for a quick, easy, convenient and constant method of making embossed printing for Braille character encoding. Prior methods of making raised printing for the blind required a movable type printing press. ==Design== The basic design of the slate consists of two pieces of metal, plastic or wood fastened together with a hinge at one side.〔〔Harry Houdini Collection (1888)〕 The back of the slate is solid with slight depressions spaced in braille cells of six raised dots arranged in a grid of two dots horizontally by three dots vertically. In the shape of an inverted braille dot of approximately diameter; depth or height; the horizontal and vertical spacing between dot centers within a braille cell is approximately cell to cell (''dot 1 center to dot 1 center horizontally'') .〔〔ADA (1994)〕〔Note: The spacing for Braille dots and cells are NOT consistent throughout the world, See ( Braille Cell Dimensions ) at tiresias.org for a chart of different standards.〕 The front of the slate has a corresponding rectangular cells with indentations in the side of the cell, over the depressions in the back so the blind user can properly position the stylus and press to form a dot.〔 There are pins or posts in the back of the slate positioned in non-cell areas to hold the paper in place and keep the top properly positioned over the back. The pins align with matching depressions on the opposite side of the slate. A slate as designed for a normal 8.5 inch piece of paper has 28 cells. It can have any number of rows, usually at least four.〔 The stylus is a short blunted awl with a handle to comfortably fit the hand of the user. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Slate and stylus」の詳細全文を読む スポンサード リンク
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