Samuel Reyher

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Samuel Reyher at the age of 77, engraving by C. Taucher

Samuel Reyher (born April 19, 1635 in Schleusingen , † November 22, 1714 in Kiel ) was a German mathematician and astronomer .

Life

Reyher's father, Andreas Reyher, was the principal at the grammar school in Schleusingen , his grandfather Sebastian Abesser was superintendent in Suhl . In 1654 he began studying mathematics and law in Leipzig . Here an influential councilor takes care of him and enables him to go on a study trip to Holland. Impressed by the scientific life in Holland, he returned to Leipzig. He works on various legal issues and gives lectures as a master's degree in the philosophical faculty. The Duke of Gotha became aware of the young Reyher, made him the tutor of his eldest son and sent him on an educational trip to Holland as his companion. After returning to Germany, Reyher decided to finish his legal studies in Holland ( Leiden ). However, the outbreak of the plague in Holland forced him to stop over in Rinteln on the Weser. Here he met the philosopher M. Watson, who had just received a call to the newly founded (1665) Christian Albrechts University in Kiel . At Watson's advocacy, Reyher was appointed as a mathematics professor there. The Prorector P. Musäus, who also comes from Thuringia, plays a supporting role. Before he took office in Kiel in 1665, however, he was still doing his doctorate in Leiden with a dissertation on the law of the firstborn.

Reyher retains astonishing productivity well into old age, and it is only at the age of 77 that he can be relieved of his teaching post. However, he held lectures until his death. Samuel Reyher is buried in Schleswig Cathedral .

As a professor at Kiel University

Although Reyher has been a professor of mathematics since 1665, he has also given law lectures since that time. In 1673 he became associate professor of the law faculty, in 1692 full professor of the Codex. The Duke of Gotha (his former student) appointed him to the Saxon council in 1682. In 1702 he became a member of the Academy of Sciences in Berlin, whose president Gottfried Wilhelm Leibniz maintained a lively correspondence with Reyher and held him in high regard. Reyher is one of the popular professors at Kiel University. At the request of his students, he organizes numerous private events in addition to the compulsory lectures and builds and repairs his own instruments. His main interest is the practical question: "How can mathematics best be used to explain and utilize natural phenomena?" Reyher makes a series of observations over the years. In 1669 he published a German version of Euclid's first 6 books . From the beginning, Reyher also gave public and private lectures on astronomy. He uses the Institutiones astronomicae (1647) by Pierre Gassendi (1592–1655). He later recommended the Institutiones astronomicae by Nikolaus Mercator (London 1676) to his students . When explaining a solar eclipse he has observed, he adheres to the teaching of Nicolaus Copernicus (heliocentric view of the world), which for him is the foundation of astronomy. In the winter of 1701/02 he treated the movement of heavenly bodies according to the systems of Copernicus, Tycho Brahe , Longomontanus and Ptolemy . The works of Huygens and Cassini serve as a guideline for information about the proportions of the sun and planets . The works of Kepler were probably not known to him.

Reyher and astronomy

In 1667 Reyher began astronomical tours on the university courtyard with instruments donated by Heinrich von Qualen, which enjoyed increasing popularity in Kiel. Later he continued the observations on a tower of the Kiel Castle . In 1702 the ducal family even accepted Reyher's invitation to "astronomical performances". This visit finally helped Reyher to set up his own observatory, which will probably be built in 1703 at Kiel Castle.

Reyher observes solar and lunar eclipses and also sunspots with his instruments (1704). It determines the noon line (with the shadow of a gnomon at the equinox) and the pole height of Kiel. In the starry sky he observed the variable Mira in the whale for many years (44 years since 1669). He also observed comets (1682) and the Andromeda Nebula (1711), but he was primarily interested in the planets and their orbits. He calculates the passage of Mercury in front of the Sun on March 5, 1707, but cannot observe it with his modest instruments.

Accurate clocks are a necessary aid for astronomical observations. That is why Reyher began designing his own timepieces at an early age. With the help of this clock he finds a year length of 365.2418 days. The today's value is 365.2422.

In the first years of his stay in Kiel, Reyher also dealt with optical issues and held lectures on them. In 1667 he set up a camera obscura for the practical demonstration of optical effects . He can only offer it temporarily, however, because he has to maintain it with his own funds and ducal support is no longer possible. He was only able to reopen it in 1703, which has since been considerably enlarged. The demonstrations in the camera obscura, which he shows several times a semester, he continued until his death.

Meteorological observations

In 1670 Reyher published a small work on air, De aere sive pneumatica , which was widely used and about which he entered into a correspondence with Leibnitz. In the course of this correspondence, Leibnitz asked him to make meteorological observations in Kiel for a few months. From then on, he measures air pressure, temperature, and humidity several times a day and describes the coverage of the sky and continues these recordings until the end of his life. In addition to the series of measurements by the Landgrave of Hesse (a student of Galileo ), Reyher's values ​​are the oldest weather records in Germany and confirm the occurrence of a “little ice age” at the end of the 17th century. In addition, Reyher carried out his first marine studies, for example on the salinity of the water, and dealt with the geodetic survey of the port of Kiel and the Schwentine .

ancestry

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Michael Reyher (1557–1634)
wine merchant
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Andreas Reyher (1601–1673)
educator
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Ottilie Albrecht (-1619)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Samuel Reyher (1635-1714)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Sebastian Abesser (1581–1638)
theologian, superintendent
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Katharina Abesser (1612–1657)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Joachim Zehner (1566–1612)
clergyman, superintendent
 
 
 
 
 
 
 
 
 
 
 
 Margaretha Zehner
 
 
 
 
 
 
 
 
 
 
 
 
 


Fonts (selection)

  • De aere sive pneumatica , Kiel 1670
  • Mathesis mosaica sive Loca Pentateuchi Mathematica mathematice explicata, cum Appendice aliorum S. Script. Locorum Mathematicorum , Kiel 1679
  • Mathematicarum disciplinarum sciagraphica generalis , Kiel 1692
  • De natura et jure auditus ac soni , Kiel 1693
  • Aqua marinae dulcedo , Kiel 1697
  • De astronomicis observationibus , Kiel 1703

literature

Web links

personal data
SURNAME Reyher, Samuel
BRIEF DESCRIPTION German mathematician and astronomer
DATE OF BIRTH April 19, 1635
PLACE OF BIRTH Schleusingen
DATE OF DEATH November 22, 1714
Place of death Kiel