Little Bits of History

March 2

Posted in History by patriciahysell on March 7, 2017

1791: The semaphore is demonstrated. Semaphore communications are a way of passing information via visual means. Towers have pivoting shutters, called blades or paddles, and the information is encoded at one end, passed along via the signals, and decoded at the receiving end, or else passed further along a route. The earliest form of distance visual communication was the smoke signal which doesn’t allow for intricacies of information. A system was described in detail to the Royal Society in 1684, but never put into use.

The French Revolution created a need for detailed, accurate information passed along distances quickly. French engineer Clause Chappe and his brothers worked on a way to accomplish this feat. They demonstrated their system on this day when they sent a message from Brulon to Parce, 16 miles away. Although sent in French, the message was “If you succeed, you will soon bask in glory”. The first system used several different mechanisms: black and white panels, clocks, telescopes, and the necessary codebooks to both encode and decode the message. The brothers continued to refine their semaphore lines and twice their devices were destroyed by angry mobs.

In 1792, Chappe was given the task of creating a line of towers to get information from Paris out to Lille, 143 miles away. This would carry information about the war between France and Austria. When the French captured Condé-sur-l’Escaut from the Austrians in 1794, it took less than an hour for the news to be received in Paris. Symbols would pass through 15 stations and weather was a factor in speed and accuracy. It took about 32 minutes for a complete message of about 36 symbols to make the trip. Another 50 stations were added by 1798 and reached to Strasbourg, 303 miles away.

Early experiments showed Chappe it was easier to see the angle of the rod than to see the presence or absence of a panel. They created a signal with black movable arms, with each position representing a letter of the alphabet. There were counterweights on the arms making it possible for just two operators to control the positions. Each of the two arms had seven positions, the long cross arm, holding them, had four possible positions for a total of 196 symbols. Night communication was unsuccessful. Both to speed up transmission and to have some sort of security, a code book was issued which used 92 of the basic symbols two at a time to give 8,464 separate coded words or phrases. A rate of 2-3 symbols per minutes was typical of the speed of transmission.

The single biggest problem in communication is the illusion that it has taken place. – George Bernard Shaw

To effectively communicate, we must realize that we are all different in the way we perceive the world and use this understanding as a guide to our communication with others. – Tony Robbins

Communication – the human connection – is the key to personal and career success. – Paul J. Meyer

Speak clearly, if you speak at all; carve every word before you let it fall. – Oliver Wendell Holmes, Sr.


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