[time-nuts] pneumatically synchronized clocks

Marc Bury marc_bury at yahoo.fr
Thu Mar 12 07:04:25 UTC 2009

Some more details from the pneumatic clocks in Paris in 1880:
(Sorry for the g00gle-style translation)

In "Le Magasin Pittoresque" in 1880, we can read an article entitled "Unification of time on the electricity and compressed air".

Regarding the pneumatic clocks, we read "... Already clocks operating with this new system, invented by Mr. Popp from Vienna, have been installed in Paris ... 
A central clock is setup so that whenever the pendulum hits the sixtieth second of a minute, there is a trigger switch that delivers the compressed air in containers, it rushes immediately into the tubes of the network, and inflate a bellows which is at their end. By blowing, the bellows raises a small lever that rotates one step in a wheel that has sixty, and each corresponding to one minute. At the same wheel is set the minute hand Dial moving a minute ...
The installation of the first fifteen dials required eighteen kilometers of pipes, and their establishment is such that all the people who live near the pipeline network that can receive time at home. It is sufficient to hook a small diversion conduct on the central pipe that brings home the compressed air provided by the administration. "

In another part, I read that the pressure pulse is maintained during the 21 first seconds of each minute.

Also I found a couple of pictures from such public clocks installed in the streets.



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