J.G.R. Andreae

Johann Gerhard Reinhard Andreae
Johann Gerhard Reinhard Andreae, portrait by Johann Georg Ziesenis ca. 1770
Born	1724 (1724) Hanover
Died	1793 (1794) (aged 69) Hanover
Occupation	German natural scientist

Johann Gerhard Reinhard Andreae (born ca. 17 December 1724 in Hanover, died 1 May 1793 in Hanover), often known as J.G.R. Andreae or I.G.R. Andreae, was a Hanoverian natural scientist, chemist, geologist, court pharmacist (Hofapotheker) and alchemist in the Age of Enlightenment. Internationally noted as a polymath, he was known throughout Europe particularly for his extensive natural history collections and for his pioneering and influential scientific work on soil and their uses for modern agriculture. He was a friend of many of the great scientists of the day, such as Benjamin Franklin, Pieter van Musschenbroek and George Shaw. The genus Andreaea, the type genus of the family Andreaeaceae of mosses, was named in his honour by his friend, the botanist Jakob Friedrich Ehrhart. Andreae was also noted as one of the major benefactors in Hanover in his lifetime.

He was the son and one of two children of the wealthy court pharmacist Leopold Andreae (1686–1730), owner of the Andreae Pharmacy (Andreae & Co.) in Hanover, and Katharina Elisabeth Rosenhagen (died 1752). His grandfather was the pharmacist Ernst Leopold Andreae (born ca. 1640). The Andreae pharmacy had been founded in 1639 with a ducal privilege from Christian Louis, Duke of Brunswick-Lüneburg and taken over by his great-grandfather Johann Andreae in 1645. It quickly came to serve the ducal court and became the official court pharmacy.

His father died early and he was raised by his mother, "a very active, intelligent and righteous woman," who arranged for him to receive an extraordinarily good education for his era. He studied all the sciences and learned all the important languages of 18th century Europe. Andreae learned the art of pharmacy in his family pharmacy, which at that time was managed by the court pharmacist Ruge from Celle. Urged by the court physician P.G. Werlhof (1699–1767) to study natural sciences, he studied geology and chemistry under Johann Heinrich Pott in Berlin, chemistry, mineralogy and metallurgy under Johann Andreas Cramer in Blankenburg, and chemistry under Hieronymus David Gaubius in Leyden. In 1747 he became head of his family's pharmacy in Hanover, at the time still owned by his mother. His mother formally ceded the ownership to him in 1751, shortly before her death. In November 1751, he married Ilse Sophie Müller (1728–1795). The marriage was a happy one, but they had no children of their own.