Almanach de la convention nationale... Early illustration of Chappe telegraph

Price: 1,250.00 USD

Paris: Dufart, 1794. [Chappe, Claude (1763-1805).] Almanach de la Convention nationale, pour l'an III de l'ere-republicaine. 12mo. [41], 77, [2]pp. Engraved frontispiece of the Chappe telegraph, engraved plate. Paris: Dufart . . . , an III [1794]. 145 x 93 mm. (uncut). Modern boards. Moderate foxing and browning, some edges a bit frayed, otherwise very good. Former owner's leather booklabel with initial "D." First Edition. The frontispiece of this Almanach contains one of the earliest illustrations of the Chappe optical telegraph system, published the same year that the telegraph became operational. The Chappe telegraph represents one of the first organized data networks. Its chief architect was Claude Chappe, who began working on designs for the telegraph in 1789. After experimenting successfully with visual signaling devices that used pendulums and modified clock faces, Claude and his three brothers devised a semaphore telegraph consisting of a large beam (the regulator) with smaller wings (indicators) mounted at each end. These semaphores, built on the tops of towers several kilometers apart, could be manipulated in various ways to signal alphabetic, numeric, and other coded symbols between stations, at a rate of one symbol every thirty seconds or so; when conditions were optimal, a message could be transmitted from Paris to Milan in about thirty minutes. Even when bad weather reduced visibility, the telegraph was still several times speedier than a man on horseback, which until then had represented the fastest reliable means of message delivery. The first optical telegraph line, consisting of nineteen stations built between Paris and Lille, a distance of 190 km. or about 120 miles, opened in July 1794. In August 1794 the telegraph was used to report two major French military victories, a happy event that appears to be commemorated in the frontispiece of the present almanac (the almanac also reprints an excerpt on ancient signaling telegraphs from Rollin's history, together with an illustration of Polybius's system of signaling by means of torches). At the time of the Chappe telegraph's replacement in 1852, its network covered more than three thousand miles and included 556 separate stations, including offshoots in Belgium and Italy. Singer et al., History of Technology 4: 644-47. Holzmann and Pehrson, The Early History of Data Networks, pp. 47-96.


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