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brass, glass, mercury
This is an elegant Crystal Outdoor Mercury Thermometer, circa 1900, made by J.M. Schmidt, Amsterdam. The base is crafted entirely from transparent glass — a thick, solid glass plate with finely faceted edges, giving the instrument a “crystalline” appearance and ensuring its resistance to moisture. The mercury capillary tube is secured with small metal clips, while painted brass brackets at the top and bottom allow the thermometer to be mounted on an exterior wall, shutter, or window frame.
The fired-on scale is double: R (Réaumur) on the left and F (Fahrenheit) on the right. Beneath the scale are the markings “Wetterfeste Scala” (“weatherproof scale”) and D.R.G.M., with J.M. Schmidt, Amsterdam inscribed below.
The impression that the scale is enclosed within the glass is achieved through a technique typical of high-quality outdoor thermometers of the late 19th century: the scale was printed on a glass substrate and fired so that the enamel fused permanently with the surface. This protected method was described at the time as wetterfeste Scala (“weather-resistant scale”). The D.R.G.M. (Deutsches Reichsgebrauchsmuster) mark indicates that the design or construction was registered as a utility model in the German Empire, pointing to a German origin of the scale technology itself, which was then supplied to Amsterdam and branded by Schmidt.
The presence of German patent markings and terminology strongly suggests that Schmidt maintained close ties with German manufacturers of precision measuring instruments.
In conclusion, this thermometer represents a refined intersection of Dutch craftsmanship and German technical innovation, preserved in remarkably original condition and retaining its clarity, functionality, and visual elegance.
