There is a certain nostalgia for a read mercury column barometer for me. In the 60s when I was finally moved from a one room school situation to a 'modern' integrated system, a couple of the upper grade classrooms and the high school science room had mercury column barometers in them, so three or four in the same school buildings.
One was the more 'modern' type seen in the science supply catalogs, all metal and spiffy. The others were ancient, wood backing in the dark stained motif that seems a recent rather than 50 year old memory.
It was there that I learned the function of a vernier that could magnify the accuracy of the readings, and also the interactions with temperature and pressures.
A few years ago I got a new, never used, Welch-Allyn, I believe but I'd have to go look at the box, mercury column barometer from an eBay seller across the state, and picked it up. The seller thought he had a jar of mercury to fill it but never found it, or his wife had taken it to hazardous waste disposal during clean-up week. I'm sure it set the team there in a twitter if indeed that is where it went.
This stuff is treated more like highly radioactive material than 'just' mercury, and I know all about mad-hatters and the potential for pollution with fluorescent tubes and broken thermometers.
But I'm thinking that the amount of surface area for a mercury pool is small, and for centuries was the standard in weather observation stations, on board ships and as mentioned almost ubiquitous in schools. I recall also doing the penny coating with liquid mercury and having it around the science lab. Never had I been around where it was heated or boiled, so that part is good.
What do the folks here think of the risk of installing the barometer, and having it filled and operating? I made one for my home when I was doing some glass blowing in high school, and had it set up with the reservoir being a 20 ml beaker that the end dipped into. I never had a fancy back stick and vernier to do readings, just eyeballed it against a high quality meter stick in the back.
Is the risk so great that I'm not appreciating it, and should stay far away, recalling how neat it was rather than setting it up again?
If I did want to set this up, I assume a well ventilated area rather than a basement corner would be best.
Finally is there a source for the 3-5 # of mercury I think I'd need to fill it and have some in the reservoir? I know it would be like gold or worse to buy, and haven't looked into any local restrictions on having the stuff. I haven't seen one of those science supply catalogs in decades, so I don't know if they still exist or not, but assume that schools must buy their stuff somewhere, and they might be a source for mercury too as they were in the past.
Just thinking about it for a project for this winter and whether or not I'll go ahead isn't something I've decided on for sure and looking for thoughts from others interested in weather observation and historic type instruments.
I'm not even going to think about how to 'automate' the readings from the barometer to have posted minute by minute on my website. Just joshing.