Woodys Antiques

Description

A superb Black Forest (German) carved wood barometer. The barometer's gauge has German indications and the mercurial thermometer is in centigrade and the French Reaumur scale. Very few Reaumur scale thermometers survive with this scale and being such an attractive piece makes this very desirable. Réaumur’s original thermometer contained diluted alcohol and was constructed on the principle of taking the freezing point of water as 0°, and graduating the tube into degrees each of which was one-thousandth of the volume contained by the bulb and tube up to the zero mark. He suggested that the quality of alcohol employed be such that it began boiling at 80 °Ré — that is, when it had expanded in volume by 8%. He chose alcohol instead of mercury on the grounds that it expanded more visibly, but this posed problems his original thermometers were very bulky, and the low boiling point of alcohol made them unsuitable for many applications. Instrument-makers generally chose different liquids, and then used 80 °Ré to signify the boiling point of water, causing much confusion. From the late 18th century mercury was used almost without exception. The barometer and thermometer are both in full working condition.

Depth 4cm / 1.50''
Height 64cm / 25.25''
Width 29cm / 11.50''