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Optical Transmission, a French Invention?
s this month’s edition coincides with Bastille Day, it seems appropriate to tell a story of a French pioneer of telecommunications whose career was stimulated by the famous event. Here is a brief summary of the inventive, determined, but ultimately tragic life of Claude Chappe.
On 12th July 1793, the official field test of, arguably, the first optical telecommunications system was conducted via Ecouen between Belleville and Saint-Martin-du-Tertre, which are to the northeast of Paris, a total distance of some 26km. The following message (translated) was transmitted successfully in just 11 minutes.
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“Daunou has arrived here. He announces that the National Convention has just authorized his Committee of General Security to put seals on the papers of the deputies.”
by Stewart Ash
The system of transmission was devised by Claude Chappe and his brothers and was called by them a “tachygraphy” or rapid writer, but later became known as the “Optical Telegraph”.
to Brûlon, unemployed. In the turmoil of the revolution, Claude’s brothers had also lost their jobs and returned home to Brûlon. Together they decided work on developing a telegraph system.
Claude Chappe was born on Christmas Day 1763 in the town of Brûlon, 200km to the southwest of Paris. He was the grandson of a Baron and, therefore of the nobility, but as a second son of ten children he was raised for the priesthood and studied to become an Abbé Commendataire.
The Chappe brothers spent the winter of 1790-91 experimenting on different methods of telegraphy, and by March of 1791 they had come up with a method they called the “Pendulum System,” but has also been called the Synchronised System.” They conducted tests between Brûlon and Parcé, a distance of some 16km. Unfortunately, very little information has survived about these experiments or the design of Synchronised System. The method of synchronising the system is unknown, but it is believed that electricity was considered and abandoned due to the lack of a suitable insulator. The tests were relatively successful and it encouraged Chappe to approach the Legislative Assembly to conduct further experiments in Paris. He did obtain permission from a commune near the Etoile to erect a
On 14th July 1789, the French Revolution began with the storming of the Bastille in Paris, and the French society changed forever. In the following months, Louis XVI and Marie Antoinette were evicted from the Palace in Versailles and moved to Paris, and the traditional privileges held by the nobility and the religious orders were abolished by a new Legislative Assembly. A side effect of this was that Claude Chappe lost his religious sinecure on 2nd November 1789 and had to return