Charles Depillon (1768 - 1805) Inventeur des Sémaphores côtiers

At the end of the XVIIIth century, when the Homeland was in danger, the Government of the Republic considered as very urgently to correspond extremely fast with all points of the Nation, and to make sure an inviolable secret in the transmissions. From 1794, the brother Chappe had generalized their invention of an « optical Telegraph ». But besides that, its construction returned this little reliable machine during storms, the found system was only syllabic, and included only 96 « syllables » that must be interpreted during the reading. Note that no secret message could pass by this mean of machine. There were many inventors of diverse models of transmissions by flags, then by telegraphs of all kinds. But no one of the models presented to the Assembly, then to the Minister of Marine, has ever had the success which expected their inventors. Charles Depillon however invented, in 1800, a system of signals for which he began by defining, not so letters, but also and especially fragments of sentences corresponding to a unique figure. Having so defined its « vocabulary » and established a Dictionary for the usual signals intended to report what was saw by the Lookouts (1), it remained to build a Semaphore able of « saying » it, by allowing a « normal » key for the use and understanding of the figures, but allowing another special key reserved to secret and military usages. Every semaphore was constituted by a mast (about 12 m) supporting three wings. These wings had 4 m length and 0,5 m wide, and were visible of the distant semaphore, so that the signals can be passed on as quickly as possible. Each of the wing was divided into sections : a black and a transparent. Every wing could pass on 7 signals separately : indeed, Depillon will consider that the position [black below] will be confused with the position : [black at the top - confused with the mast] ; there are then 4 oblique positions, and both horizontal positions (black to the left, and black to the right). If 2 other wings were to be added to the first one, the powers of 7 are going to be added, and in spite of the increasing number of positions not to be used for avoid confusion of different signals of the wings, the total of available signals will reach 301. The system was applied to all the Dictionary of the selected sentences, the indications of direction, distance, or name of the nations to which belonged ships crossing along the coasts. The secret consisted « simply » in adding wherever in the passed on signals, a figure fixed by the General Staff, what had the effect of moving the meaning of all the signals for a « foreign » observer, but for a member of the General Staff, to supply very precise indications and at the same time very fast on the movement of ships along the French coast. But Ch. Depillon died before to see his invention in earth. The ministry of the Navy had selected him on the basis of his invention, but a friend of him, Louis Léon JACOB was in charge from 1806 (i.e. one year after the death of Depillon) to build the entire semaphorique line. Strategically speaking, Jacob could take all the « rights » of invention of this semaphore, because it was well seen by the ministry, and because the system was very reliable. This system established under Napoleon Ier was neglected for the greater part from 1824; nevertheless, Napoleon III will take it back from 1861, and while perfecting semaphores (use of the metal instead of the wood, made of swivelling semaphores), was keeping the system of figures associated with Dictionaries of naval sentences. The system was so familiar to seamen that even the Morse system has had difficulties to be accepted in the minds. Some Semaphores will still be in active service until 1937. (1)- Literally « Guetteurs » (Watchman) : a team of two keepers that were in the charge of watching the neighbouring semaphores, to pass on the signals when they were occurring, and to transmit the activities of all ships on the coasts