"DSK" wrote in message
.. .
Got one of these?
http://outdoors.webshots.com/photo/2...35692614zFojSZ
or
http://tinyurl.com/erfzd

http://outdoors.webshots.com/photo/2...35692614KkQrJT
or
http://tinyurl.com/g8t7r

Want one? Sorry, I already gave awa the drive turbine for the prairie
masker. That was a cute little bucket wheel.

When you get right down to it, aren't all gauges differential?
I asked my students what they thought would happen if I dropped a compound
gauge into a vacuum chamber and dropped the pressure to 500 microns. Most of
them guessed wrong, and were surprised that the gauge read zero before,
during, and after the vacuum was achieved.
Scout