Julius Christian Johannes Zeller (24 June 1822, Mühlhausen am Neckar – 31 May 1899,

Cannstatt Bad Cannstatt, also called Cannstatt (until July 23, 1933) or Kannstadt (until 1900), is one of the outer stadtbezirke, or city boroughs, of Stuttgart in Baden-Württemberg, Germany. Bad Cannstatt is the oldest and most populous of Stuttgart's ...

) was a German

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

. He was born to Gottlob Zeller and Christiana Friedrike Moser.Germany Birth And Baptism Index 1558-1898 Originally trained in mathematics,

geography Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, an ...

and

theology Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing the ...

, in 1874 Zeller became Director of the Seminary in

Markgröningen Markgröningen is a town in the district (Kreis) of Ludwigsburg, Baden-Württemberg, Germany. It is known for its fine historic buildings, many in the ''Fachwerk'' German architectural style, and its annual Shepherds' Run. Markgröningen is on ...

and a girls'

orphanage An orphanage is a residential institution, total institution or group home, devoted to the care of orphans and children who, for various reasons, cannot be cared for by their biological families. The parents may be deceased, absent, or ab ...

. In 1882 he became a member of the

Société Mathématique de France Lactalis is a French multinational dairy products corporation, owned by the Besnier family and based in Laval, Mayenne, France. The company's former name was Besnier SA. Lactalis is the largest dairy products group in the world, and is the sec ...

. The following year, on 16 March 1883, he delivered a short account of his congruence relation (

Zeller's congruence Zeller's congruence is an algorithm devised by Christian Zeller in the 19th century to calculate the day of the week for any Julian or Gregorian calendar date. It can be considered to be based on the conversion between Julian day and the calendar ...

), which was published in the society's journal. He was later awarded the Order of Friedrich, First Class, and the Ritterkreuz of Württemberg. He retired in 1898, and died in the following summer.

Works

On calendrical calculations

Each of these four similar papers deals firstly with the day of the week and secondly with the date of

Easter Sunday Easter,Traditional names for the feast in English are "Easter Day", as in the ''Book of Common Prayer''; "Easter Sunday", used by James Ussher''The Whole Works of the Most Rev. James Ussher, Volume 4'') and Samuel Pepys''The Diary of Samuel P ...

, for the Julian and

Gregorian Calendar The Gregorian calendar is the calendar used in most parts of the world. It was introduced in October 1582 by Pope Gregory XIII as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years dif ...

s. *
Die Grundaufgaben der Kalenderrechnung auf neue und vereinfachte Weise gelöst
', Zeller, Chr., Württembergische Vierteljahrshefte für Landesgeschichte, Jahrgang V 1882. *

' par M. Ch. Zeller, Bulletin de la Société Mathématique de France, vol.11, Séance du 16 mars 1883 *

' von Rektor Chr. Zeller, Mathematisch-naturwissenschaftliche Mitteilungen des mathematisch-naturwissenschaftlichen Vereins in Württemberg, Ser. 1, 1 1885 *

' von Chr. Zeller, Acta Mathematica, Vol. 9 1886-87, Nov 1886 He also produced a reference card

On number theory

''See

number theory Number theory (or arithmetic or higher arithmetic in older usage) is a branch of pure mathematics devoted primarily to the study of the integers and integer-valued functions. German mathematician Carl Friedrich Gauss (1777–1855) said, "Mat ...

.'' * ''Ein neuer Beweis des Reziprozitäts-Theorems'', Berlin 1872 * ''De numeris Bernoulli eorumque compositione ex numeris integris et reciprocis primis'', Paris 1881 * ''Zu Eulers Rekursionsformel für die Divisorensummen'', Stockholm 1884

References

External links

Biography
in German)

1822 births 1899 deaths 19th-century German mathematicians {{Germany-mathematician-stub