The Telegraph, Part 1


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Professor McAdams's lecture about Chappe's optical telegraph

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  • The Telegraph, Part 1

    1. 1. The Telegraph (1): Erasing Time, Compressing Space Presentation by Mindy McAdams Week 8.1 / MMC 2265
    2. 2. The Optical Telegraph: 1792-3 <ul><li>Invented by Claude Chappe (1763 – 1805), a Frenchman </li></ul><ul><li>In 1794 , first messages sent between Paris and Lille, France </li></ul><ul><li>No electricity used </li></ul><ul><li>Line of sight only (no good at night or on rainy days) </li></ul>
    3. 3. Timing Is Everything <ul><li>1789: Storming of the Bastille in Paris </li></ul><ul><li>1792: Chappe asks the French legislature for funding to build telegraph ; he is denied </li></ul><ul><li>1792–1797: French at war with Austria and Prussia </li></ul><ul><li>1793: Chappe asks the French legislature for funding (again); he gets money! </li></ul><ul><li>1793: King Louis XVI and Marie Antoinette executed </li></ul><ul><li>1793–1794: In the Reign of Terror, at least 18,000 people are executed (many on the guillotine) </li></ul>
    4. 4. Distance and Speed <ul><li>This is not the first time people had tried to communicate between two distant points </li></ul><ul><li>The goal: Get the message to its destination faster than a man (or a horse) could travel </li></ul>Top: African drums were used to send a signal to a nearby village. Bottom: Homing pigeons were used by the ancient Persians and Greeks.
    5. 6. Chappe’s System (Hardware) <ul><li>The vertical bar can be moved to four positions (only two were used) </li></ul><ul><li>The two boards (one on each end) could each be moved into seven positions </li></ul>
    6. 7. Chappe’s Code <ul><li>98 possible positions </li></ul><ul><li>Six position reserved for instructions </li></ul><ul><li>92 could be employed </li></ul><ul><li>With a codebook, the 92 positions could be made to represent 8,464 words or phrases (not letters) </li></ul>92 positions of the Chappe telegraph
    7. 8. “Hardware” and “Software” <ul><li>The hardware was slow </li></ul><ul><li>The software made it more efficient </li></ul><ul><li>The human factor: Two men required at each station had to repeat (accurately) the signal sent by the previous station </li></ul>
    8. 9. Chappe's telegraph stations, c. 1840 Most stations were about 3 to 4 miles apart
    9. 10. Getting the Message <ul><li>Visibility </li></ul><ul><ul><li>Average 6 hours a day in summer </li></ul></ul><ul><ul><li>Average 3 hours a day in winter </li></ul></ul><ul><li>A line of telegraphs transmitted 1 to 3 signals per minute </li></ul><ul><li>Speed improved over time </li></ul><ul><li>It took 15 to 30 minutes to decode the message at the end of the line </li></ul>
    10. 11. Government Control <ul><li>Even though the French government changed drastically several times, each government supported the telegraph system </li></ul><ul><li>Napoleon provided funds to expand the network along with his growing empire (1804 – 1814) </li></ul><ul><li>Military operations justified the huge expense needed to run the network </li></ul><ul><li>Public use of the network was forbidden until 1850 (except for transmission of lottery numbers ) </li></ul>
    11. 12. Republic and Empire <ul><li>France had its revolution (1789 – 1799) </li></ul><ul><li>Then seesawed between republic and empire for 80 years </li></ul><ul><ul><li>1792–1804: First Republic </li></ul></ul><ul><ul><li>1804–1814: First Empire (Napoleon I) </li></ul></ul><ul><ul><li>1848–1852: Second Republic </li></ul></ul><ul><ul><li>1852–1870: Second Empire (Napoleon III) </li></ul></ul><ul><ul><li>1870–1940: Third Republic </li></ul></ul>
    12. 13. Communications and Democracy <ul><li>Claude Chappe, among others, argued that the network of telegraph stations would enable the nation-state to coalesce </li></ul><ul><li>Fast communication over long distances: The key to a republican style of government? </li></ul><ul><li>Critics (who supported empire) said France was “too large” to operate as a republic </li></ul>
    13. 14. Connections: The Age of Reason <ul><li>“ Modern” philosophy began in the 1600s (with Descartes, who died in 1650) </li></ul><ul><li>Followed the Renaissance (da Vinci, Michelangelo, Machiavelli; the Protestant Reformation) </li></ul><ul><li>Preceded the Enlightenment (Voltaire, Rousseau, Thomas Paine), where the seeds of democracy were sown </li></ul>
    14. 15. Connections: The Nation-State <ul><li>State : political and geopolitical ( note: the liberal state) </li></ul><ul><li>Nation : cultural and/or ethnic (language, religion, customs) </li></ul><ul><li>Contrast: An empire is a state usually consisting of many diverse (conquered) nations </li></ul>
    15. 16. Other Countries Copied France <ul><li>Britain and others built their own optical telegraph networks , copying Chappe’s ideas </li></ul><ul><li>An aide to the King of Sweden learned of Chappe’s system by reading a magazine in 1794 </li></ul>
    16. 17. The Telegraph (1): Erasing Time, Compressing Space Presentation by Mindy McAdams University of Florida