optical telegraphs

Quelle: http://www.aqpl43.dsl.pipex.com/MUSEUM/COMMS/telegraf/telegraf.htm

Timescale:

Aug 1794 Semaphore telegraph inaugurated in France by Claude Chappe
Aug 1795 First trials in England
Sept 1795 Surveyor appointed to lay out Lines
Jan 1796 London-Deal Line completed
??? 1796 London-Portsmouth Line completed

May 1806 Plymouth extension completed
June 1808 London-Yarmouth Line completed
May 1814 Shutter Telegraph dismantled
May 1816 Construction of Admiralty Semaphore Telegraph begins

Feb 1845 Electric Telegraph installed London-Portsmouth
Dec 1847 Admiralty Semaphore Telegraph closes
Mar 1849 Admiralty Electric Telegraph completed


The timescale above shows that the new technology was adopted, and a successful system constructed, with quite impressive speed.

 The Deal and Portsmouth Lines were completed in 1796; a trial Portsmouth-Plymouth "ping" took 20 minutes.

 Above: part of a contemporary drawing of the Admiralty Shutter Telegraph, and the codes for a few of the letters. Note the telescope pointing out of the window of the "officer's cabin", to observe the next station. Unfortunately the artist's grasp of perspective seems to have been a bit feeble.

Above: a map of the routes of the Admiralty Shutter Telegraph. The semaphore system that replaced it took slightly different routes.