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Object Overview
This compact Art-Deco Wall Hair Hygrometer, dating to around 1930 and produced by the German manufacturer of scientific instruments G. Lufft of Stuttgart, represents an elegant example of a domestic meteorological instrument from the interwar period. The instrument is housed in a circular case measuring approximately 90 mm in diameter.
The case is turned from solid pearwood, a material long valued in German instrument making for its stability, fine and uniform texture, and excellent properties for precision machining. The front of the case is finished with a rosewood veneer, giving the surface a deep warm brown tone and a refined polished sheen. At the top of the case a brass suspension ring is fitted, allowing the instrument to be mounted on a wall. This combination of materials is characteristic of German instruments of the interwar period, where a stable pearwood base was paired with a more decorative and valuable veneer.
The instrument is fitted with a circular brass dial, protected by a flat glass with a beveled edge set into a brass bezel. The scale is printed in Dutch, indicating that the instrument was produced for the export market of the Netherlands or Belgium. The dial is graduated from 20 to 100 percent relative humidity and is accompanied by the qualitative indications droog (dry), normaal (normal), and vochtig (humid). In the lower portion of the dial appears the inscription “relatieve vochtigheid der lucht in procenten” (“relative humidity of the air in percent”), while the word “Hygrometer” is prominently printed beneath the scale.
n/a
hygroscopicity
brass, glass, hair, steel, wood
Behind the dial is concealed the hair hygrometer mechanism, based on the hygroscopic properties of organic fibers. Instruments of this type employ a carefully prepared and degreased human hair which lengthens as atmospheric humidity increases and shortens as the air becomes drier. These minute changes in length are transmitted through a small lever mechanism hidden beneath the dial, converting the linear movement of the hair into the rotational motion of the pointer across the humidity scale. Despite its mechanical simplicity, this principle—developed in the eighteenth century—remained one of the most reliable methods for measuring relative humidity well into the twentieth century.
Compact, elegant, and carefully constructed, this Lufft hygrometer illustrates the characteristic combination of scientific instrument and refined interior object typical of the interwar era. Instruments of this kind were intended not only for the practical monitoring of indoor humidity, but also served as decorative scientific objects reflecting the enduring public interest in meteorology and environmental observation.