wrote in message
...
On Fri, 14 Nov 2008 22:16:02 -0000, "Graham." wrote:



"Kevin Poole" wrote in message
...


Rod wrote:
wrote:
On Fri, 14 Nov 2008 08:39:02 -0800 (PST), Andy Dingley
wrote:

On 14 Nov, 16:14, "Graham." wrote:
I just saw an "expert" on "Flog It tell a guy always to keep
his barometer upright, an never ever lie it down.
As advice aimed at an audience that watches daytime TV, then it's not
too bad. You don't want them spilling mercury, I doubt if many could
spell aneroid let alone tell what sort of barometer they had.

Is the mercury not sealed in? Is it not to prevent the mercury
splitting with the problem of getting it all back together again?

Last time I looked closely at one, it was 'sealed' by what I assume was
a
small piece of animal skin, tied. The sort of seal that keeps dust out,
not mercury in - I doubt it would have been strong enough to hold back
the weight of the mercury when still, let alone when sloshing around.


There are two problems transporting a typical mercury wheel barometer.
If
you don't tilt it at all the mercury bounces around, and will very
easily
punch the end out of the top of the tube, as it will if you lie it down
too quickly. If you lay it flat, it dribbles out of the reservoir end
of
the tube. I always recline them, gently, until the mercury is firmly up
to the top of the bulb, then plug the open end with either a cork or
something similar, and carry them at an angle.

I would be very surprised if James Lewis didn't know this - I've been to
many of his auctions, and he's always struck me as bright and
knowledgeable. He's also an excellent auctioneer, who can push over 180
lots per hour through without appearing to hurry.

As Andy says - it's a lot less messy if you treat them all as mercury
rather than all as aneroid.

Sounds to me that this wasn't an aneroid instrument at all,
it just looked like one. (the word means "dry")
I hadn't heard of a mercury wheel barometer until you mentioned
it. Can you point me to a diagram on how it works, I cant find one.

Does this help
http://www.quicksilver-barometers.co...ation.html#wks
It does, and it looks like I owe Mr Lewis an apology!

--
Graham.

%Profound_observation%