A rare Scottish Regency mahogany cased travelling sympiesometer, by Adie & Son, early 19th century, the hinged door enclosing the engraved silvered brass register plate, signed and numbered Adie & Son, Edinburgh No.1507, bearing Fahrenheit...

A rare Scottish Regency mahogany cased travelling sympiesometer, by Adie & Son, early 19th century, the hinged door enclosing the engraved silvered brass register plate, signed and numbered Adie & Son, Edinburgh No.1507, bearing Fahrenheit thermometer and sympiesometer tube, with manually operated calibration slide to side of register, the case with brass clasps and suspension ring to top, 55.5cm high, 4.1cm wide, 3.2cm deep Note: Alexander Adie (1774-1858), invented and patented the sympiesometer in 1818. The patent entitled "An Improvement On the Air Barometer" was developed primarily to replace the marine barometer. The top part of the tube is filled with hydrogen whilst the lower part and the open bulb contains a coloured almond oil. Hydrogen, being affected by both pressure and temperature, makes it necessary to first take a reading from the mercury thermometer using the index finger at the top of the sliding scale and then reading the barometric pressure, ie. the level of the oil, against the lower part of the sliding scale, the figure was then recorded on the dial below. Alexander and his son, John were the only instrument makers to be elected to the Edinburgh Royal Society and worked from premises in Princes St. from 1832-57. Please note Roseberys do not guarantee the working condition of scientific instruments offered for sale.