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.