Originally Posted by Russel Gulch
I think they're all wrong...the glass does not "contain" the pressure.
The pressure bellows (or whatever) is a sealed unit at the back of the instrument.
5/10....2nd half is correct.
The aneroid is indeed a sealed unit at the back of the instrument. It is surrounded by the air in the instrument case. The case is sealed except for the connection to the static system. Since the glass makes up part of the case it does, indeed, "contain the pressure" (even if the difference between the static pressure and ambient is, usually, very small).
OC619