Keywords: Rees's Cyclopaedia - Richard Lovell Edgeworth's optical telegraph.png Richard Lovell Edgeworth's proposal for an optical telegraph system in Ireland Each indicator was used to display the number of a particular unit to form a four-figure number which then represented characters and words via a codebook For further explanatory text see entry on TELEGRAPH volume 35 of the Cyclopædia Rees's Cyclopædia Plates Vol IV TELEGRAPH Fig 1 and 2; from a digital scan at http //archive org/details/cyclopaediaplates04rees Delineator Creator John Farey Jr Engraver Creator Wilson Lowry 1802-1820 serial publication of the source work PD-old-X-1923 100 Retouched picture Cropped adjusted levels removed fig 12 various paper stains and blemishes and digital artifacts grayscaled Morgan Riley http //archive org/stream/cyclopaediaplates04rees page/n325/mode/2up Morgan Riley Signal towers Images from Rees's Cyclopædia Images by John Farey Jr |