[time-nuts] pneumatically synchronized clocks

[Russell Rezaian]

Also it seems that there was at least one company making pneumatic 
master/slave clock systems for buildings.  I've found references to 
these made by the Hahl company out of Chicago.

Not sure if any of these are still in service anywhere.

I know pneumatic building automation systems are still actively in 
use today, I believe the office building where I work uses pneumatic 
thermostats for part of the HVAC control.
--
Russell