Special barometer / hygrometer, Tendancy - Alexander Adie - December 23rd, 1818 - model A053. The mahogany cabinet with curved glass, aluminium-coloured brass front plate with a storm glass next to the barometer tubes and a hygrometer - mounted above the tubes. The two tubes are filled with a liquid. A U-shaped tube with an open end is filled with a red liquid; and a closed thermometer tube is filled with a blue liquid, mounted parallel to each other. The thermometer measures both Celsius and Fahrenheit and the barometer measures in millbar / hPa. On the back is a sticker from the French Meteo Consult. The Tendency Barometer was patented by Alexander Adie on 23rd December 1818. It was used by James Clark Ross during his expeditions to Antarctica. The barometer is in good condition The lot will be sent by registered mail. Pick-up in Rotterdam is possible.