Communicating by Optical Telegraph: What's the top speed of semaphore?

Illustration for article titled Communicating by Optical Telegraph: What's the top speed of semaphore?

Well into the age of email, we're used to lightning quick communication. Waving around old flags looks pretty silly now. But this method of signaling was once built into a revolutionary communication network, and you wouldn't believe how fast it could go.


There was once a time when the fastest way to get news, of any kind, was "horse." And horse moved at a speed of about thirteen miles per hour, provided both it and its rider could move at a gallop. A horse going from Venice to Amsterdam made it in about half a week. A carrier pigeon would make it in half the time - provided the bird made it at all. Something had to be done, and so the telegraph was invented - in 1791. The seventeen hundred was not the golden age of technology. Although, like all centuries, it had its advances, scientific equipment was still the domain of the gentleman scientist and the rarefied scholar. Society was still awaiting the Victorian Age's leap forward in engineering and infrastructure. But it wasn't the electrical telegraph that first shrunk communication time. It was the optical telegraph.

Towers were built about twelve miles apart, each having a telescope and a little wooden semaphore with two arms. Each arm could be put in one of seven positions. Each wooden semaphore could be turned in four positions. The resulting 196 total positions allowed plenty different signals, all of which could signify a letter, a certain particular code, or a often-used phrase. Each telegrapher looked at the last tower to get a symbol, changed his own symbol with the use of a lever, and then swiveled his telescope around to check which letter the last person had put up. The symbols came at the rate of three per minute - necessitating economy in the number of words used, but the towers were massive successes.

The French were the first to build a network. They were in the grip of the Revolution, and trying their hand at more scientific ways to do everything, from communications to time keeping. Naturally, they were fighting at their borders with other nations, and the first message of the optical telegraph, going from Lille to Paris with happy news of a victory over the Austrians, moved at eight hundred and fifty miles an hour, moving faster than typical modern planes.

The tower systems blossomed over Europe and over America. Towers sprang up over France, Sweden, and down into Spain and Italy. The towers weren't truly integrated across nations, since electricity reared its more-reliable head before the system could be firmly established, but the message that would take weeks in the hands of a human, and days by animal messenger could suddenly make it from Amsterdam to Venice in one hour.

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Via Low Tech Magazine



When did seventeen hundred start to mean the seventeenth century? I've noticed it a lot of late and it always throws me. To me, the Seventeen Hundreds lasted from 1700 to 1709. So, when somebody uses Seventeen Hundred(s) to refer to a whole century, I have to consciously remember they don't mean what I think they mean.

It's not as if Seventeen Hundred uses less letters. I suppose 1700s might in text speak, but I don't understand what benefit it brings to prose.

Confused and mildly irritated by all this newfangled stuff :)