Lasers, light and telephones
1. Early forms of optical communication: In 1588, when the Armada was sighted sailing up the English Channel for the invasion of England, a warning signal was sent to the Queen by the lighting of bonfires on a chain of hilltops from Devon to London. This was a common method of sending important mess...
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Format: | Article |
Language: | English |
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1975-06.
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Online Access: | Get fulltext |