Johann Heinrich Schulze

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

Life

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

In the period 1720-1732 he was a professor at the University of Altdorf and then to 1744 at the University of Halle. In Halle he had mainly held the chair of Antiquities, came to an entitlement to the next vacancy arises in the Faculty of Medicine. This professorship he could compete waiting period only after several years. His greatest achievement is the fact that he founded the history of medicine. His students, including Johann Joachim Winckelmann was, he explained the text editions of ancient authors. Schulze is considered an important numismatists of the 18th century. His coin collection he used for academic teaching. The collection is preserved in the Archaeological Institute of the University of Halle.

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

Discovery of the light sensitivity of silver salts

Schulze had placed a glass vial with scabbard water on a subject illuminated by the sun window sill. There was a discoloration of the vagina water. This had to do with the fact that the vagina water had already been used before and thus contained some silver nitrate. Through experiments, he tried to find the cause of the discoloration. It was unclear whether this was due to the heat radiation or to the light of the sun. As Schulze 1717 silver nitrate heated in an oven, he noted that this is not darkened. Thus he could not rule out heat as a trigger for the blackout. When he partially opaque abklebte a glass bottle containing silver nitrate and exposed to sunlight, discolored after some time only the uncovered areas. The covered areas remained unchanged. With these experiments, he demonstrated clearly that silver salts are sensitive to light.

Schulze published his findings in 1719 in the Bibliotheca Novissima Oberservationum ac Recensionum under the title Scotophorus per phosphorothioate Inventus, seu experimentum Curiosum de effectu radiorum solarium. A reprint of the same title took place in 1727 in the Acta Physico - medica of the Leopoldina. Eder, who pointed to this discovery Schulze in 1913 in a publication, only knew the emphasis.

Honors

Halle's sculptor Heidi Wagner Kerkhof created in 1979 a bronze medal memory.

Writings

• Scotophorus per phosphorothioate Inventus: seu experimentum Curiosum de effectu radiorum solarium. In: Bibliotheca Novissima observationum et recensionum. Ed. JC Franck, cesarean section V, No. VII Halae Magdeburgicae 1719, pp. 234-240 ( Digitized edition )
• Scotophorus per phosphorothioate Inventus, seu experimentum Curiosum de effectu radiorum solarium. In: Acta Physico - medica, Leopoldina, Volume 1, 1727, pp. 528-532
• Historia medicinae. A rerum initio ad annum urbis Romae DXXXV deducta; acced. tabulae aeneae, chrono logica et indices copiosi / studio Io. Monath, Lipsiae 1728
• Johann Heinrich Schultzens treatise of the Stone Chur by internal Artzeneyen become known at all, and especially of the recently English. Franckfurt 1740 ( Digitized edition of the University and State Library Dusseldorf )
• Joh. Schulz's chemical experiments. Waysenhaus, Hall 1745 Digitized edition of the University and State Library Dusseldorf
• Io. Henrici Schulzii theses de materia medica. Publisher: Christoph Strumpff. Halae: Orphanotropheus, 1746 Digitized edition of the University and State Library Dusseldorf