Hello
I have recently been given a Shortland Smith barometer as a present. It is wood and brass, circular in shape, with spokes similar to a ship's wheel around the edge. I have worked out how to move the fine brass needle using the screw on the face. However.....how do I move the black needle? There are 4 screws on the back; three are unlabelled and the 4th is a smaller screw that apparently is used to compensate for height above sea level. So my question is: can anybody explain to me how to set the black needle correctly, please?
