Johann Friedrich Benzenberg

Background

Johann Friedrich Benzenberg was born near Elberfeld, Germany on May 5, 1777, to Heinrich Benzenberg, a Protestant clergyman and theological writer, and Johanna Elisabeth.

Education

Benzcnberg studied theology in Herborn and Marburg, but later, in Gottingen, became interested in the natural sciences. He received his doctorate from the University of Duisburg in 1800, with a thesis “De determinatione longitudinis per Stellas transvolantes.”

Career

In 1805 Benzenberg became a professor of mathematics at the Lyceum in Dusseldorf; later he directed the land survey of the duchy of Berg (1805-1810), organized its land registry, established the teaching of surveying, and wrote several textbooks for surveyors. He gave up this position and lived in Switzerland during the French occupation of the Rhineland. After his return to Germany, Benzenberg devoted himself to studying science as a private citizen; he simultaneously began to gain influence as a writer on politics, particularly constitutional law and economics.

Benzenberg had begun an original scientific investigation as early as 1798, while he was still a student at Gottingen; his independent work there, in which his collaborator was H. W. Brandes, was encouraged by the physicists A. G. Kastner and Georg Lichtenberg. With Brandes, he made the first simultaneous observations of meteors that made use of terminal points on a basis of either ten or fifteen kilometers.

They then used these measurements to determine for the first time the height and velocity of the meteors. These data corroborated Chladni’s theory of the cosmic origin of meteorites and their relation to fireballs, which had been published in 1794 and which was still hotly disputed. Benzenberg himself used his data to formulate a theory that “the shooting-stars are stones from moon-volcanoes.” As late as 1839 (by which time it was widely assumed that meteorites were small heavenly bodies that rotated around the sun or the earth), he defended this idea against Olbers and Arago, among others.

Benzenberg’s experiments on falling bodies were as original as his work on meteors. In these investigations he determined the displacement toward the east of falling lead spheres - in the tower of the Michaelis Church in Hamburg in 1802, and in a mine shaft in Schlebusch, in the Earldom of Mark, in 1804. He thereby demonstrated the revolution of the earth some fifty years before Foucault did. That such a demonstration might be possible had been suspected by Newton, to be sure, but Robert Hooke’s experiments of 1679 were inconclusive and those of Domenico Guglielmini in 1791 were highly inaccurate.

In his later years, Benzenberg occupied himself with ballistic experiments and published further works on geodetical, astronomical, and physical subjects. Two years before his death he built a small observatory on his own property in Bilk. In his will, he left his observatory to the city of Düsseldorf, providing a grant to pay the salary of a resident astronomer.

Achievements

• Benzenberg's major achievement was in the codiscovery of the upper‐atmospheric (nontropospheric) location of meteors. Also, he was a founder of a private observatory at Bilk, which he funded and which became an important center of minor‐planet research.
  
  Another Benzenberg’s achievement was in his experiments on falling bodies, which were as original as his work on meteors. In these investigations he demonstrated the revolution of the earth some fifty years before Foucault did.

Works

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  • Beschreibung Eines Einfachen Reisebarometers: Nebst Einer Anleitung Zur Leichten Berechnung Der Berghohen 1811
  • Ueber Papiergeld Besonders in Bezug Auf Des Grossherzogthum Sachsen-Weimar-Eisenach: Oder Beurtheilung Zweyer Pläne Welche Für Die Tilgung 1802
  • Ueber Preussens Geld-Haushalt und neues Steuer-System 1820
  • Ueber Handel Und Gewerbe, Steuren Und Zölle 1819
  • H Henmessen Mit Der Quecksilberwaage Fur Pariser, Rheinl Nder Und Londoner Linien 1821
  • Die Warmen Quellen in Aachen Und Die Warmen Quellen in Wimpfen 1832
  • Briefe Geschrieben auf einer Reise nach Paris 1804
  • Die Staats-Verfassungen Deutschlands 1845
  • Die Rechenkunst Und Geometrie Für Die Geometer Des Grossherzogthums Berg 1811
  • Die Verwaltung Des Staatskanzlers Fursten Von Hardenberg 1821
  • Rother's Bericht Über Die Haupt-Verwaltung Der Preussischen Staatsschulden 1820

Politics

Benzenberg’s political views were those of an enlightened liberal who advocated a strong central monarchy.

Connections

Father:

Heinrich Benzenberg

He was a Protestant clergyman and theological writer.

Mother:

Johanna Elisabeth

collaborator:

Heinrich Brandes

In 1798, whilst still a student at the University of Göttingen, Benzenberg and Heinrich Wilhelm Brandes studied the atmospheric altitude of meteors, collecting the first evidence that they were inside the atmosphere.

References

• Johann Friedrich Benzenberg (1777-1846)
• Dictionary of scientific biography
  1981
• The Biographical Encyclopedia of Astronomers
  2009
• Meteor Showers and their Parent Comets
  2006