On Thu, 22 Apr 2004 16:10:00 GMT, Dave Shrader
wrote:

Cecil Moore wrote:

David.Shrader wrote:

If it's a closed tube then the length does not change with angle.


I may be wrong, cuz I'm not very mechanical, but it seems to me
that a column of mercury in a tube with a vacuum at the top
and a reservoir of mercury at the bottom would change height
of column depending on the angle of the column's deviation from
vertical. It seems to me that when the column is horizontal,
there would be no vacuum at all in the tube.
--
73, Cecil http://www.qsl.net/w5dxp

OK. A manometer as opposed to a thermometer.


No, a barometer.

1. Thermometer -- sealed at both ends -- height depends on
temperature.

2. Manometer -- open at both ends -- one end open to atmosphere; other
end open to space whose pressure you want to measure relative to
atmosphere; displacement from balanced level in each column dependent
on pressure differential.

3. Barometer -- sealed at top; open at bottom, which is submerged in
sizable puddle of mercury; vertical height, from surface of reservoir
to top of column (assuming adequately long tube and adequately large
mercury reservoir) dependent on pressure, but length of mercury column
dependent on tilt of tube. (sec or csc function, IIRC.)