Johan Georg Forchhammer (26 July 1794 – 14 December 1865) was a

Danish Danish may refer to: * Something of, from, or related to the country of Denmark People * A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark * Culture of Denmark * Danish people or Danes, people with a Danish a ...

mineralogist Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proce ...

and

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althoug ...

Early life and education

Forchhammer was born at

Husum Husum (, frr, Hüsem) is the capital of the ''Kreis'' (district) Nordfriesland in Schleswig-Holstein, Germany. The town was the birthplace of the novelist Theodor Storm, who coined the epithet "the grey town by the sea". It is also the home o ...

Schleswig The Duchy of Schleswig ( da, Hertugdømmet Slesvig; german: Herzogtum Schleswig; nds, Hartogdom Sleswig; frr, Härtochduum Slaswik) was a duchy in Southern Jutland () covering the area between about 60 km (35 miles) north and 70 km ...

. He studied at the universities of

Kiel Kiel () is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 246,243 (2021). Kiel lies approximately north of Hamburg. Due to its geographic location in the southeast of the Jutland ...

and

Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...

from 1815 to 1818.

Career

Forchhammer then joined Hans Christian Ørsted and Lauritz Esmarch in their mineralogical exploration of Bornholm, and took a considerable share in the labors of the expedition. In 1820 he obtained his

doctorate A doctorate (from Latin ''docere'', "to teach"), doctor's degree (from Latin ''doctor'', "teacher"), or doctoral degree is an academic degree awarded by universities and some other educational institutions, derived from the ancient formalism ''li ...

by a chemical treatise ''De mangano'', and immediately after set out on a journey through

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

Scotland Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a Anglo-Scottish border, border with England to the southeast ...

and the

Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway bet ...

. In 1823 he was appointed lecturer at Copenhagen University on chemistry and mineralogy; in 1829 he obtained a similar post in the newly established polytechnic school; and in 1831 he was appointed professor of mineralogy in the university, and in 1848 became curator of the geological museum. From 1835 to 1837 he made many contributions to the

geological survey A geological survey is the systematic investigation of the geology beneath a given piece of ground for the purpose of creating a geological map or model. Geological surveying employs techniques from the traditional walk-over survey, studying outc ...

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , establish ...

. On the death of Hans Christian Ørsted in 1851, he succeeded him as director of the polytechnic school and secretary of the

Academy of Sciences An academy of sciences is a type of learned society or academy (as special scientific institution) dedicated to sciences that may or may not be state funded. Some state funded academies are tuned into national or royal (in case of the Unit ...

. In 1850 he began with

Japetus Steenstrup Johannes Japetus Smith Steenstrup FRS(For) H FRSE (8 March 1813 – 20 June 1897) was a Danish zoologist, biologist, and professor. Life Born in Vang, Thy on 8 March 1813, he held a lectorate in mineralogy in Sorø until 1845 when he became ...

and

Jens Jacob Asmussen Worsaae Jens Jacob Asmussen Worsaae (14 March 1821 – 15 August 1885) was a Danish archaeologist, historian and politician, who was the second director of the National Museum of Denmark (1865–1874). He played a key role in the foundation of scientifi ...

various anthropological publications which gained a high reputation. As a public instructor Forchhammer held a high place and contributed potently to the progress of his favorite studies in his native country. He interested himself in such practical questions as the introduction of gas into Copenhagen, the establishment of the fire-brigade at Rosenborg and the boring of artesian wells. In 1865, Johan Georg Forchhammer conjectured that the ratio of major

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

s in samples of seawater from various locations was constant. This constant ratio is known as Forchhammer's Principle, or the Principle of Constant Proportions. Forchhhammer's theory was proven correct in 1884 by Prof William Dittmar following extensive analysis of sea-water samples taken during the

Challenger expedition The ''Challenger'' expedition of 1872–1876 was a scientific program that made many discoveries to lay the foundation of oceanography. The expedition was named after the naval vessel that undertook the trip, . The expedition, initiated by Wi ...

. Among his more important works are ''Lærebog i. de enkelte Radicalers Chemi'' (1842); ''Danmarks geognostiske Forhold'' (1835); ''Om de Bornholmske Kulformationer'' (1836); ''Dit myere Kridt i Danmark'' (1847); ''Bidrag til Skildringer af Danmarks geographiske Forhold i deres Afhængighed af Landets indre geognostiske Bygning'' (1858). A list of his contributions to scientific periodicals, Danish, English and German, will be found in the Catalogue of Scientific Papers published by the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

of London. One of the most interesting and most recent is "On the Constitution of Sea Water at Different Depths and in Different Latitudes", in the ''Proceedings of the Roy. Soc.'' xii. (1862-1863). He was a Commander of the Order of the Dannebrog, and was a member of the

Royal Danish Academy of Sciences and Letters {{Infobox organization , name = The Royal Danish Academy of Sciences and Letters , full_name = , native_name = Det Kongelige Danske Videnskabernes Selskab , native_name_lang = , logo = Royal ...

from 1825. In 1863, he was elected a foreign member of the Royal Swedish Academy of Sciences. He died at

. He was the brother of August Friedrich Wilhelm Forchhammer, father of Johannes Nicolai Georg Forchhammer, and grandfather of Johannes Georg Forchhammer.

Personal life

Christoffer Wilhelm Eckersberg - Portrait of Louise Christiane Fugl

Forchhammer married twice. He married Louise Christiane Fugl (1804–1831), a daughter of ''kancelliråd'' U. N. Fugl (1768 – 1817), in 1826. She died in 1831 and he then married her half-sister Emilie Mariane Fugl (1815 – 1882). They lived in the Professor's House at

Nørregade Nørregade (literally "North Street") is a street in central Copenhagen, Denmark, linking Gammeltorv in the south with Nørre Voldgade in the north. Landmarks in the street include Church of Our Lady, Bispegården, St. Peter's Church and Folk ...

8–10 in Copenahgen from 1833 and until his death in 1865. Forchhammer's son

Johannes Forchhammer Johannes Nicolai Georg Forchhammer (20 March 1827 – 9 July 1909) was a Danish philologist. He was born in Copenhagen as a son of Johan Georg Forchhammer. He was a nephew of August Friedrich Wilhelm Forchhammer. He finished his secondary educati ...

(20 Narcg 1827 – 18 July 1908), the only child from his first marriage, was a linguist and headmaster of

Aalborg Cathedral School Aalborg Cathedral School ( da, Aalborg Katedralskole) is the oldest gymnasium in North Jutland, Denmark. There are about 80 teachers at Aalborg Cathedral School and approximately 760 students who are assigned to 24 high school classes and 6 High ...

and

Herlufsholm Herlufsholm School ( da, Herlufsholm Skole og Gods) is a private day and boarding school by the River Suså in Næstved, about south of Copenhagen. Herlufsholm was founded in 1565 as a boarding school for "sons of noble and other honest men" o ...

. Gis second marriage was without children. Forchhammer died on 14. December 1865 and is buried in Assistens Cemetery.

Awards

Forchhammer was a member of the

from 1825. He was awarded the Order of the Dannebrog in 1939 and was created Commander of the Order of the Dannebrog in 1860. He was elected as a member of the

American Philosophical Society The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...

in 1862.

Written works

* ''De mangano'', 1820 * "Danmarks Geognostiske Forhold", in ''Universitetsprogram'', 1835. * ''Det nyere Kridt i Danmark'', 1847. * ''Lærebog i Stoffernes Almindelige Chemie'', 1842. * ''De enkelte Radikalers Almindelige Chemie'', 1842 (textbook). * ''Bornholmske Kulformationer'', 1836. * ''De vigtigste Sætninger af den uorganiske Chemie'', 1838. * ''Bidrag til Skildringen af Danmarks geographiske Forhold i deres Afhængighed af Landets indre geognostiske Bygning'', 1858. * ''Om Søvandets bestanddele og deres Fordeling i Havet'', 1859. * ''Almenfattelige Afhandlinger og Foredrag'', 1869. * Selvbiografi i ''Universitetes Program'', November 1903.

References

External links

Johan Georg Forchhammer
at geni.com {{DEFAULTSORT:Forchhammer, Johan Georg 1794 births 1865 deaths People from the Duchy of Schleswig Danish mineralogists Danish geologists Members of the Royal Swedish Academy of Sciences Danish people of German descent Commanders of the Order of the Dannebrog