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Object Overview
This Lambrecht’s Standard Mercury Barometer, dating from around 1960, was produced by the renowned German manufacturer Wilhelm Lambrecht. It was widely used at meteorological stations, schools, laboratories of all kinds, as well as in mining and gas industries, and even at shooting ranges and similar facilities. For aneroid barometers, it served as a calibration reference instrument, while for private individuals observing atmospheric phenomena, it represented an almost indispensable scientific aid.
The instrument’s body is mounted on a cast aluminium base with a black hammer-finish lacquer coating and equipped with a plumb line for precise vertical alignment. The total weight of the barometer is 5.5 kg.
It features a massive nickel-plated scale covering the range of 630 – 790 mm Hg, graduated in 1 mm increments, allowing readings to be taken with a vernier to 1/10 mmHg and estimated to 1/100 mmHg. Both the scale and the vernier are adjustable by a rack-and-pinion mechanism. The sliding vernier ring, which encircles the mercury tube completely, enables precise, parallax-free readings. To set the barometer to the zero point, a V-shaped index at the lower end of the movable scale is aligned with its mirror reflection in the mercury meniscus, forming a perfect cross when properly adjusted.
30534
cistern
aluminium, glass, mercury, steel
The mercury cistern is made of steel and glass. The Bunten trap, which separates the glass tube into upper and lower sections, captures any air that might accidentally enter the lower part of the tube, rendering it harmless and preventing it from affecting the readings. The internal bore of the tube at the upper end is 8 mm, ensuring that friction between the mercury and the glass walls has no appreciable influence on accuracy.
The barometer is equipped with a mercury thermometer with a Celsius scale ranging from −15 °C to +50 °C, graduated in 1 °C divisions.
For transportation, the barometer is equipped with a special sealing mechanism operated by a large knurled nut beneath the cistern, allowing the mercury column to be securely closed before moving the instrument.
The barometer measures the difference in mercury levels between the cistern and the glass tube. Before taking a reading, the lower end of the scale must be adjusted to match the mercury level in the cistern. Zero adjustment is made using a rack-and-pinion screw with a knurled head at the bottom of the scale, while another knurled screw at the top controls the vernier movement for the actual reading. The vernier ring is aligned so that its lower edge coincides with the top of the mercury meniscus. The last main scale division below the vernier zero line gives the whole millimetres, while the vernier indicates the tenths. To determine the exact barometric pressure, the number of whole millimetres is combined with the fractional value corresponding to the vernier division that aligns perfectly with a line on the main scale.
In its elegant design and precise workmanship, this barometer perfectly embodies the scientific rigor and aesthetic craftsmanship that distinguished Wilhelm Lambrecht’s instruments throughout the 20th century.
The barometer was donated to our foundation by a private individual from their personal collection.