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Re: Problem with a Barometer



On Tue, 04 May 1999 09:40:36 -0800 John Mallinckrodt
<ajmallinckro@CSUPOMONA.EDU> writes:
On Tue, 4 May 1999, Roger Haar wrote:

I have an odd problem with a mercury barometer. It
reads too large of an atomospheric pressure. Here at the U
of AZ the Atmospheric Science Dept has two nearby stations
from which I can get readings. These report something like
27.2 inches ( NOT corrected to sea level) and I get 29.5
inches.

Roger,

Apparently you've successfully created an "ultravacuum." We all know
that the "vacuum ain't nothin'" these days. Most likely you have simply
managed to reduce the level of vacuum fluctuations in the region
above your mercury column a la the Casimir force. I say, publish before

the effect perishes.

John

If it really is an ultra vacuum, please send me a few micropascals of it
if you can spare some . Meanwhile check for trapped denucleated drops
of heavy water in the mercury column.

Herb Gottlieb from New York City
(Where we use mercury barometers to check the height of buildings that
are serviced by friendly janitors)