The Ross Expedition Tendency Barometer Thermometer, A54, is a unique presentation quality tendency barometer and thermometer. The mercury free barometer is similar to water barometers, and is a safe alternative to mercury filled instruments. Mounted in an exquisitely crafted wood and curved glass case, the D&D A54 is a tribute to the famous explorer James Clark Ross, discoverer of the magnetic North Pole. His ship, the Erebus, is pictured at the top of the instrument and a map of the Antarctic is pictured below. It consists of two liquid filled tubes. One tube in a U-shaped which is open ended and filled with a red 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. When the red fluid level is above the blue, stormy weather is predicted (low pressure allows the red fluid to move up the tube). The thermometer measures in both Celsius and Fahrenheit and the barometer measures in millibars/ hPa. The overall instrument measures 20 inches high by 6.7 inches wide and weighs 3 pounds. An absolutely beautiful presentation piece that will last for generations. Normally ships in 1-3 business days. MSRP: $238.00.

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