Instant Messaging In The 1700's

Slashdot pointed me to this fascinating article on the optical telegraph system in late 18th century/early 19th century Europe. It consisted of a series of towers spaced a few miles apart, each equipped with two wooden semaphore arms and two telescopes.

From the article:

Every tower had a telegrapher, looking through the telescope at the previous tower in the chain. If the semaphore on that tower was put into a certain position, the telegrapher copied that symbol on his own tower. Next he used the telescope to look at the succeeding tower in the chain, to control if the next telegrapher had copied the symbol correctly. In this way, messages were signed through symbol by symbol from tower to tower. The semaphore was operated by two levers. A telegrapher could reach a speed of 1 to 3 symbols per minute.

Pretty slow, but a lot faster than a post rider, provided nobody was dallying at the controls.

The very first message – a military victory over the Austrians – was transmitted in less than half an hour. The transmission of 1 symbol from Paris to Lille could happen in ten minutes, which comes down to a speed of 1,380 kilometres an hour. Faster than a modern passenger plane – this was invented only one and a half centuries later.

Of course, the electrical telegraph arrived in the mid 1800's, and all of those semaphore towers faded into history. As Paul Harvey would say, "and now you know the rrrrrrrrrest of the story!"