For hundreds of year's mercury stick barometers were the most accurate way to measure air pressure and indicate changes in the weather. Many households throughout Britain are still home to a traditional mercury stick barometer and Metcheck are often asked for advice on how to remove any air bubbles that may have developed over time in the glass tube.
Faults Info To remove air "bubbles", the tube has to be manipulated separately from the wooden barometer frame. If it is necessary to remove the tube from the frame do so carefully by removing any covers and clips holding the glass capillary in place.
1. Holding the tube upright, remove the cap with integral plunger and place your thumb over the open end of the tube.
2. Turn the tube upside down and "pump, jiggle or gently tap" the tube on a hard surface. The mercury will push pas the air locks, forcing them upward towards the open end of the tube.
3. When all the air is out or near the bend in the tube, invert the tube to its normal position. The mercury descending inside the tube will push the air into the reservoir. It may be necessary to lightly "pump" the tube in a downward motion to aid this purpose.
It may be necessary to repeat this process several times to remove all the trapped air.
4. With the tube upright fit the valve cork and allow the mercury to fill the tube by slowly leaning the tube sideways.
5. Refit the tube into the wooden barometer frame.
To print this useful barometer guide click here. We hope the above steps have been helpful but if you would like further advice or assistance feel free to email a member of our sales team.