mercury :-(

["John S. Denker" <jsd@MONMOUTH.COM>]

Tom Ford wrote:
> ... electrical connection
> every second to update a counter. A good student project if they have not
> made you get rid of the Hg already.

I would not let a student near mercury whether They allow
it or not.  The chance of a spill is too great, and the
cost of a good cleanup is too high.  The cost of a bad
cleanup is high, too -- remember you and/or a colleague
will have to be in that room for many hours a day for
years on end.....

And there's no need.  Most things that formerly were done
with mercury can be done these days in other ways, just as
nicely or even better:
 -- mercury switch --> reed switch + magnet
    or optical switch + interrupter
 -- Hg diffusion pump --> silicone diffusion pump
    or turbopump or ion pump
 -- various explosive compounds --> other explosive compounds