'Wedgwood's highly improved noctograph', c 1842.
© Science Museum / Science & Society Picture Library
The 'noctograph', orginally patented in 1806 as a 'Stylographic Writer', was designed to help blind people write. The device used 'carbonated paper', made by soaking paper with printers' ink. Once dried, the paper was fitted in the writing frame between two sheets of plain paper and a metal stylus was used to transfer the ink onto the plain paper. The bottom sheet was the original and the top sheet, the writing on which was reversed, was the copy. This explanatory drawing is signed W R Wedgwood of 84 Lombard Street, London.