Does anyone know anything about the pnuematic clock co. How does a clock work on pressure (vacuum)?

I don't know anything about them but there are several patents on file for them, you can check them out here;

http://www.google.com/patents?...=10&spell=1&oi=spell

Also there are articles about a Pneumatic Clock Company out of Paris France.

http://books.google.com/books?...ck%20company&f=false

Just realized yours says HAHL Clock Company Chicago, here is a patent for possibly your clock

http://www.google.com/patents?...HAHL%20clock&f=false

Thanks Tom! I think I'll leave this one in the junk shop where I found it, until the city decides to run some Paris like underground air lines. My compressor leaks so badly that the clock probably wouldn't keep very good time