D & D Barometer Nautical Tendency Barometer
D&D Barometers of Belgium A46 - Nautical Tendency Barometer with Thermometer.
The Tendency Barometer was patented on December 23, 1818 by Alexander Adie. It consists of two liquid filled tubes. One tube in a U-shaped which is open ended and filled with a red, non-mercury fluid; and one closed thermometer tube filled with a blue fluid, mounted parallel to each other.
When the fluid levels are the same, the weather is changing.
When the red fluid level is below the blue fluid level, the weather is fair (high pressure pushes the red fluid down in the tube).
When the red fluid level is above the blue, stormy weather is predicted (low pressure allows the red fluid to move up the tube).
By measuring the amount of difference between the red and blue fluids on the tendency dial, you get the local weather forecast for the next 12-24 hours.
The beautiful wood frame is made from European walnut with black trim and the face has colorful nautical flags along the right side.
The thermometer measures in Fahrenheit and Celsius. The tendency dial also measures air pressure in millibars.
The D and D A46 Nautical Tendency Barometer comes fully assembled and includes a calibration kit to adjust the unit for altitudes above sea level.
Size and Weight: 19" H x 7" W, Approx. 3 LBS
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