This type of barometer was invented by  Evangelista Torricelli in
mid 17th Century - But popularized  by the German poet and multi-
talent Johann Wolfgang von Goethe it is now known under his name.

The glass is filled half with colored water.  Inside is a trapped
air bubble. Over the open spout the outer air pressure effect the
water-levels inside vs. outside ...

    H I G H   AIR PRESSURE   L O W E R S   the  OUTER LEVEL
      L O W   AIR PRESSURE   R A I S E S   the  OUTER LEVEL

  L O W  AIR PRESSURE is associated with  S T O R M Y  WEATHER.

Therefore this barometer type was used for & named "STORM GLASS".

... sofar the  T H E O R Y   -  AND WHAT ABOUT THE  P R A X I S ?
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                    I got this NICE DEVICE from a good friend ...
(A)
FILLING IS A MASS:
Mix destilled water with a shot of ink. Do the whole procedure in
the sink: Fill a bit in the open spout. Close the open spout with
the thumb, turn the glass around  until the filling is inside the
body. Continue step-by-step until the body is half filled.
(B)
CALIBRATE / RESET THE BAROMETER:
Turn the glass  until the spout has air-connection with the inner
air-bubble.
(C)
E X P E R I M E N T S :
Place the barometer inside(!) IN A FLAT BOWL in permanent shadow.
In praxis THIS GOETHE-BAROMETER  is working more as a THERMOMETER
than a barometer if not in an air-conditioned room: As the summer
temperature rised from  70°F to 100°F ( to 40°C ), the inner AIR-
BUBBLE EXPANDED and pressed the colored water out of the spout...
... W H A T   A   M A S S  !!!

       ... I have passed "THIS D***D THING" to another friend ;-)

                       A Better Way To Do Weather-Forecasting ...
impressum:
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© C.HAMANN      http://public.BHT-Berlin.de/hamann       07/08/14