Semaphore Telegraphs
1794 Claude Chappe set up a line of mechanical telegraphs (termed "T" telegraph after their shape) between Paris and Lille.
1796 The first line worked so well that another line of telegraphs, from Paris to Landau, in Bavaria, was established.
The telegraph system was subsequently much developed all over France. The term "semaphore" was first coined by the French in 1801 to describe the apparatus that they set up along the coasts of France and her dependencies.
By 1796 lines of signalling had also been set up in England, from the Admiralty in London to Portsmouth and to Deal. This "shutter" telegraph system seems to have been designed by the Rev. John Gamble, chaplain to the Duke of York. On a clear day a short message could easily be sent from London to Portsmouth, about 70 miles, in five minutes.
There was also a line of telegraphs from London to Great Yarmouth, but it was closed down in 1814
1810 The various stations along the east coast of England were converted from the old system of signalling with flags and balls, into semaphores consisting of a single post with three separate arms.
1815 the Admiralty announced plans to establish a permanent system of stations using “Semaphore” - a machine with movable arms.
1816 A new system, based on the invention of Sir Home Popham, was introduced on a trial basis. An experimental line was constructed between the Admiralty and Chatham. The Semaphores were made by Messrs Maudslay and the telescopes were supplied by Dollond.
1822 The new semaphore line opened between The Admiralty and Portsmouth.
The cost of working the telegraph between London and Portsmouth was estimated at between £3000 and £3500 a year; the system could be used perhaps 7 hours per day in summer, and five hours in winter; it was found there were about 108 days a year when the weather was not conducive to signalling.
1822 Colonel Pasley of the Royal Engineers finalised his much simpler system that was subsequently adopted widely, including at sea in 1874 as a method of conversational signalling. This continued in use for many years and was simplified into a manual version.
c.1827 A telegraph was established between Holyhead and Liverpool, based on a system invented by Lieut. B. L. Watson.
1837 Cooke and Wheatstone patented the electric telegraph
1847 The use of the London-Portsmouth semaphore system was discontinued.
1851 Watson organised semaphore telegraph systems in other parts of the country on a commercial basis; the Holyhead line devolved upon another naval officer, Lieutenant William Lord, who much improved it, the stations now being more numerous and better equipped.
1861 The Liverpool system was closed.