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Geographic Distribution of Think Tanks |
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Think tanks are most common in the U.S. and also very widespread in Europe. Still they are an international phenomenon, with at least one or two such institutions in nearly every country of the world.
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Chappe's fixed optical network
Claude Chappe built a fixed optical network between Paris and Lille. Covering a distance of about 240kms, it consisted of fifteen towers with semaphores.
Because this communication system was destined to practical military use, the transmitted messages were encoded. The messages were kept such secretly, even those who transmit them from tower to tower did not capture their meaning, they just transmitted codes they did not understand. Depending on weather conditions, messages could be sent at a speed of 2880 kms/hr at best.
Forerunners of Chappe's optical network are the  Roman smoke signals network and Aeneas Tacitus' optical communication system.
For more information on early communication networks see Gerard J. Holzmann and Bjoern Pehrson, The Early History of Data Networks.
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