On Tue, 20 Apr 2004 12:41:55 -0500, "Steve Nosko"
wrote:

Cap the bottom to fix
this. Leave a little air/vacuum/(a.k.a. mercury vapor) on top if you must
use a glass tube.

Hi Steve,

It doesn't work that way. The mercury will create its own void -
thing called gravity and the pressure of the atmosphere around us are
in competition (even if the tube is sealed). Fill it to absolute
capacity (no reservoir) and you will either pop the tube (thing called
thermal expansion) or draw a vacuum.

Pressure, gravity, temperature - all things mercury is sensitive to.
It would be easier to herd cats.

73's
Richard Clark, KB7QHC