Heinrich Friedrich Gretschel

Heinrich Friedrich Gretschel (21 October 1830, in Prietitz near Elstra, Germany – 2 February 1892, in Freiburg, Switzerland) was a German mathematician and scientist.

In 1847, Gretschel became a student at the Technischen Bildungsanstalt (now TU Dresden). On 28 April 1851 he was enrolled at Leipzig University, where he studied mathematics, natural sciences and ancient languages. In 1854, he passed the examination for the higher school office in the first ranking and became a teacher at the Leipziger Gesamtgymnasium.

On 2 January 1873 he was promoted by the Faculty of Philosophy of the University of Leipzig as a result of completing the mathematical dissertation, Lehrbuch zur Einführung in die organische Geometrie ("Introduction to organic geometry").

Gretschel wrote and lectured in a wide range of fields, publishing books about meteorology, physics, chemistry, astronomy, geometry and cartography. Gretschel also wrote about the construction of stringed instruments in the violin family and co-wrote a book on the construction of the pianoforte with Julius Blüthner, Lehrbuch des Pianofortebaues (1872).