1798 __ Wireless telegraphy using freshly severed frogs' legs
‣ Comment : Salvá's first proposal is similar to the one described in Scots Magazine (for February 17, 1753). It uses a separate wire for each letter of the alphabet, a Leyden jar to transmit a spark across these wires, but peculiarly, instead of the pith ball electroscopes and indicators, Salvá specifies a number of people, one for each wire. Upon receiving a sensible shock, each of these people, presumably servants, was to call out the name of the letter of the alphabet to which he corresponded. A twenty seventh person, presumably literate, was to write down the message so shockingly spelled out. This is probably the system that Salvá operated between Madrid and Aranjuez in 1798 (. (C. MacKechnie Jarvis.) — Whether Salvá's abandonment of pith-ball electroscopes in favor of human receivers was due to problems with electrical dissipation in the moister climate of Barcelona, a cheaper labor pool, or the relative ease of transcription of 26 vocal sources into a coherent message are questions that only further researches into his work might reveal. Nonetheless, the scene of a hall filled with the sighs, whispers and moans of humanity being shocked into literacy seems an appropriate and emblematic image for the events of 1789. [...] Toward the final years of the 18th century, after Galvani's discovery of animal electricity, Salvá formulated a revised proposal for the telegraph using freshly severed frogs' legs as the indicators. Each leg, when stimulated by the spark, would dance and in so doing, jerk a slip of paper on which the corresponding letter of the alphabet had been written. In the first decade of the new century, after Volta's invention of the electrochemical battery, Salvá proposed a scheme that proves politically correct to this day: electrical current flowing through the wires causes electrolytic decomposition of water, the resulting bubbles of hydrogen serving to indicate the letter selected. There is historical evidence that this last system was actually realized in the early years of the new century, transmitting messages over a distance of several kilometers in 1804. Another thirty years were to pass before the American painter Samuel Morse discovered and solved what was by then a "sweet" problem, building his first working telegraph model on a canvas stretcher. Morse's critical contribution, the code of dots and dashes, not only allowed the transmission of any written message on a single wire, but provided the prototype of a digital metaphor for communication that has reached its apex in our own time. (Paul DeMarinis 1998)
‣ French comment : On se souvient que la découverte de l'électricité statique, obtenue par frottement, avait inspiré à un mystérieux C.M. une idée de télégraphe électrique, publiée en 1753 dans le "Scots Magazine". Or il en alla de même des expériences de Galvani, trahissant bien le besoin qu'a éprouvé de tout temps l'être humain de pouvoir communiquer à distance. A peine le savant de Bologne avait-il suggéré que l'électricité trouvait sa source dans le système nerveux de ses batraciens que le médecin espagnol Francisco Salva y Campillo proposait déjà de construire un télégraphe alimenté par une batterie de cuisses de grenoulles. Batterie non réchargeable... et rapidement périssable. (Pierre Zweiacker, Jacques Neirynck, "Fluide vital: contes de l'ère électrique", PPUR presses polytechniques, 2005, p. 61)
‣ Source : MacKechnie Jarvis, C. (1977), “The Origin and Development of the Electric Telegraph”, in “The Electric Telegraph, An Historical Anthology”, ed. G. Shiers Arno Press, New York.
‣ Urls : http://www.well.com/user/demarini/messenger.html (last visited )
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