Reaumur Barometer, Early 19th Century

Weather forecasting is a scientific question that has always been of vital interest to many economic sectors. It was in the 18th century that an excellent answer was provided by the engineer Reaumur, using the effects of atmospheric pressure on a column of mercury contained in a long glass tube. This method is illustrated by our barometer, supplemented by an alcohol thermometer in degrees Celsius and a mercury thermometer in degrees Farenheit. An adjustable cursor at the top of the barometer's mercury column is used to compare the previous reading with the current one. The woodwork is veneered with mahogany. At the top, a plaque indicates the name of the optician from whom it was purchased. It is a little erased from being cleaned. In very good original condition, only the cursor wheel seems to have lost the ratchet that made it rise, otherwise it remains functional. First third of the 19th century.