MDIA 1010 Lecture Notes - Lecture 11: Electrical Resistance And Conductance, Electrical Network, Maritime Flag
22 Dec 2016
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Shutter telegraph england: created by george murray, shutter telegraphs were a form of optical telegraphy used in britain. Opening and closing the six panels in various combinations would indicate the letters. Use of shutter telegraphs was discontinued after end of napoleonic wars. First semaphore line in the us between martha"s vineyard and boston: semaphore lines in the us were used for maritime news. Semaphore station in spain: surviving optical telegraph station in spain, typically, optical telegraph stations were positioned on hilltops for visibility, changes in weather and transmission/reading errors were obstacles to this kind of telegraphy. The electrostatic charges transmitted through a wire would move tiny balls made of pith: some authors have identified the anonymous author as charles marshall, but this remains controversial. Early experimental telegraph by samuel sommering (1809: used one wire for each letter of the alphabet.
