Removing mercury from 19th century stick barometer

I am a conservator in private practice and am submitting this query
for a client who does not have access to the DistList. My client is
the collections manager for a historic house museum which has a 19th
century stick barometer mounted on a wall in the museum. One day the
barometer was removed from the wall and placed flat on the floor and
some of the mercury spilled onto the floor. An environmental clean
up agency was called to deal with the spilled mercury, but they
would not touch the object and only removed the mercury that had
spilled.

At the request of the director, the collections manager is exploring
the option of emptying the barometer and disposing of the mercury to
prevent future spills. (The total amount of mercury is less than 2
tablespoons.) I explained that removing the mercury would compromise
the integrity of the object. I am not familiar with the mechanisms
of stick barometers but in searching the internet it appeared from
images of other 19th century barometers that the system is enclosed
and there would be no danger of mercury leaks unless the glass tube
was broken. The curator does not believe that the object has been
broken which may mean that the barometer is missing some end cap or
other closing device.

Does anyone have experience with 19th century stick barometers and
know whether they are open systems? How do others display or store
objects that contain potentially dangerous materials as integral
components of the object? Are there any opinions about removing the
mercury and displaying the object empty? (Yes, the integrity of the
object would be severely compromised, but some of the mercury has
already been lost.)

I would appreciate any advice or information from related
experience.

Diane Fullick
Fullick Conservation LLC


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                  Conservation DistList Instance 21:22
                Distributed: Monday, September 10, 2007
                       Message Id: cdl-21-22-019
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