Johann Heinrich Schulze

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Johann Heinrich Schulze

Johann Heinrich Schulze (born May 12, 1687 in Colbitz , † October 10, 1744 in Halle (Saale) ) was a German polymath . He was the discoverer of the sensitivity of silver salts to light . He is one of the most outstanding scientists of the founding era of the Academia Fridericiana Halensis .

Life

Johann Heinrich Schulze was born on May 12, 1687 in Colbitz, the son of a tailor. He became a half-orphan at an early age and received his schooling from 1697 to 1704 in the orphanage of August Hermann Francke . From 1704 to 1717 he studied medicine , chemistry , philosophy and theology at the University of Halle .

In the period from 1720 to 1732 he was a professor at the University of Altdorf and then until 1744 at the University of Halle. In Halle, he held the professorship of antiquities, in addition to being eligible for the next vacant position in the medical faculty. He was only able to take up this professorship after several years of waiting. His most important achievement can be seen in the fact that he founded the history of medicine. He explained the text editions of ancient authors to his students, including Johann Joachim Winckelmann . Schulze is considered an important numismatist of the 18th century. He used his coin cabinet for academic teaching. Today this collection forms the basis of the Archaeological Museum of the Martin Luther University Halle-Wittenberg and has largely been preserved.

Schulze married Johanna Sophie Corvinus in Colbitz in 1719. He is the father of Johann Ludwig Schulze (1734–1799). Schulze died on October 10, 1744 in Halle.

Discovery of the sensitivity of silver salts to light

Schulze had placed a small glass bottle with parting water on a window sill lit by the sun. There was discoloration of the separating water. This was due to the fact that the septic fluid had already been used and thus contained some silver nitrate. He tried to find the cause of the discoloration through experiments. It was unclear whether this was due to thermal radiation or the light of the sun. When Schulze heated silver nitrate in an oven in 1717, he found that it did not darken. So he could rule out heat as a trigger for the darkening. When he taped a glass bottle that contained silver nitrate, partially opaque, and exposed it to sunlight, only the uncovered areas changed color after a while. The areas covered remained unchanged. With these experiments he clearly demonstrated that silver salts are photosensitive.

In 1719 Schulze published his results in the Bibliotheca Novissima Oberservationum ac Recensionum under the title Scotophorus pro phosphoro inventus, seu experimentum curiosum de effectu radiorum solarium . A reprint under the same title took place in 1727 in the Acta physico-medica of the Leopoldina.

Charles-François Tiphaigne de la Roche (1722–1774) took up these discoveries in his novel Giphantie (the title is an anagram of his name) in 1760 to describe them as a way of doing photography .

Josef Maria Eder , who referred to Schulze's discovery in a publication in 1913, only knew the reprint from 1727.

Memorial stone for Johann Heinrich Schulze in Colbitz

Honors

On August 27, 1721 Johann Heinrich Schulz with the academic surname Alcmaeon was elected member ( matriculation no. 354 ) of the Leopoldina . In December 1738 he became an honorary member of the Russian Academy of Sciences in Saint Petersburg . Since 1960 he has given its name to Schulze Cove in Antarctica. The Halle-based sculptor Heidi Wagner-Kerkhof created a bronze commemorative medal in 1979.

Fonts

literature

  • Julius Leopold Pagel :  Schulze, Johann Heinrich . In: Allgemeine Deutsche Biographie (ADB). Volume 33, Duncker & Humblot, Leipzig 1891, p. 4 f.
  • Hans-Dieter Zimmermann:  Schulze, Johann Heinrich. In: New German Biography (NDB). Volume 23, Duncker & Humblot, Berlin 2007, ISBN 978-3-428-11204-3 , p. 725 f. ( Digitized version ).
  • Josef Maria Eder: Sources for the earliest beginnings of photography up to the XVIII. Century , Halle ad Saale: Knapp 1913, pp. 97-104
  • Josef Maria Eder: Johann Heinrich Schulze , KK Graphische Lehr- und Versuchsanstalt, Vienna 1917
  • Wolfram Kaiser, Arina Völker: Johann Heinrich Schulze (1687-1744). Scientific contributions from the Martin Luther University Halle-Wittenberg 1980/45. Halle (Saale): Dept. of science journalism at Martin Luther University 1980.
  • Hans-Dieter Zimmermann: About the necessary correction of a memorable year. JH Schulze discovered the sensitivity of silver nitrate to light as early as 1717 . In: Fotografie 42 (1988), pp. 162-163.
  • Hans-Dieter Zimmermann: The discovery of the sensitivity of silver salts to light. A new dating of the experiments of Johann Heinrich Schulze . In: Rundbrief Fotografie 14.1 (2007), pp. 12-14.
  • Stephan Lehmann, Numophylacium Schulzianum . In: »Winckelmann. Modern Antiquity «, catalog of the exhibition in the Neues Museum from April 7 to July 2, 2017, Klassik Stiftung Weimar, ed. by E. DÉCULTOT u. a. (Munich 2017), pp. 154–156.

Web links

Individual evidence

  1. ↑ Charles-François Tiphaigne de la Roche: Giphantie ( Memento of 19 September 2006 at the Internet Archive ), 1760, accessed on September 7, 2016
  2. ↑ Member entry of Johann Heinrich Schulze at the German Academy of Natural Scientists Leopoldina , accessed on August 9, 2018.
  3. ^ Foreign members of the Russian Academy of Sciences since 1724. Johann Heinrich Schulze. Russian Academy of Sciences, accessed November 11, 2015 (Russian).
  4. ↑ Memorial medal, medal Johann Heinrich Schulze, bronze, cast, diameter 93 mm
personal data
SURNAME Schulze, Johann Heinrich
ALTERNATIVE NAMES Alcmaeon
BRIEF DESCRIPTION German polymath
DATE OF BIRTH May 12, 1687
PLACE OF BIRTH Colbitz
DATE OF DEATH October 10, 1744
Place of death Halle (Saale)