Jean Brunner

Jean Brunner or Johann Josef Brunner (September 24, 1804 – November 29, 1862) was a French precision instrument maker of Swiss origin.

Biography

Brunner was born in the Swiss town of Balsthal in 1804. He was the son of the renowned locksmith Johann Josef Brunner and began working as his father's apprentice. After moving to Basel, he worked for three years for a scale manufacturer while studying mathematics and drawing at night. At the age of 22, he entered the Polytechnic Institute in Vienna and began building physics instruments. In 1828, he settled in Paris, adopted the French version of his name, and became Jean Brunner. After working for Frédéric Hunzinger and Vincent Chevalier, he established his own company at 34 Rue des Bernardins and later moved to 183 Rue de Vaugirard. He built and perfected nearly all precision instruments used at the time, from microscopes to equatorial mounts for large telescopes, as well as the geodetic ruler (known as the Ibáñez-Saavedra ruler) designed for Spain by Carlos Ibáñez de Ibero, based on the model used by Swiss geodesist Ferdinand Rudolph Hassler for the coastal geodetic survey of the United States, where he introduced the meter in 1805.

In 1839, he participated in the 9th edition of the "Exhibition of French Industrial Products" and received a silver medal for one of his achievements. In the following edition, in 1844, he presented various precision instruments such as theodolites, microscopes, compasses, and a 60 cm diameter astronomical circle for which he was awarded a gold medal. He achieved the same success at the 1849 exhibition.

In 1845, at the suggestion of François Arago, he built an equatorial mount for the large telescope at the Paris Observatory. He obtained French citizenship by decree on July 5, 1850. That same year, he was admitted to the Bureau des Longitudes, first as a manufacturing assistant and later as a manufacturer.

During the 1855 Paris Universal Exposition, he served as a member of the jury. Although this prevented him from competing for awards, he presented various astronomical and optical instruments, as well as a ruler designed to measure geodetic bases used to determine the dimension and accuracy of geodetic triangulations. This measuring instrument consisted of a double ruler made of platinum and brass, 4 meters long and equipped with microscopes. The construction of this device took approximately two years. The thermal expansion of the device was thoroughly studied by its Spanish designers, Carlos Ibáñez de Ibero and Frutos Saavedra Meneses. This ruler was compared with Borda's rule No. 1, the double rod designed for the Delambre and Méchain meridian arc survey, which was used to determine the length of the meter. This comparison further guaranteed the metrological traceability between the meter and the French toise used as a geodetic unit in Prussia. The ruler created by Jean Brunner was used to measure the central geodetic baseline of Spain. Brunner's participation in the project earned him the title of Knight of the Order of Charles III.

Shortly before his death, Jean Brunner took part in the 1862 London Universal Exposition, where he presented, among various geodetic and optical instruments, a 42 cm meridian circle built for the Viceroy of Egypt.

After his death in 1862 in Paris, the workshop passed to his two sons, Émile Brunner and Léon Brunner. The company was renamed Brunner Frères. The family business disappeared in 1895 with the death of Émile Brunner, one year after the death of his brother Léon. Members of the Brunner family are buried in Montparnasse Cemetery.

External links

• Johann Josef Brunner: Microscope Museum
• Brunner Company History: Kambeck