Franz Ulrich Theodor Aepinus (13 December 172410 August 1802) 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, mathematical structure, structure, space, Mathematica ...

scientist A scientist is a person who conducts scientific research to advance knowledge in an area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosophica ...

, and natural philosopher residing in the

Russian Empire The Russian Empire was an empire and the final period of the List of Russian monarchs, Russian monarchy from 1721 to 1917, ruling across large parts of Eurasia. It succeeded the Tsardom of Russia following the Treaty of Nystad, which ended th ...

. Aepinus is best known for his researches, theoretical and experimental, in

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...

and

magnetism Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particle ...

Early life

He was born at Rostock in the Duchy of Mecklenburg-Schwerin. He was descended from Johannes Aepinus (1499–1553), the first to adopt the Greek form (αἰπεινός) of the family name Hugk or Huck, and a leading theologian and controversialist at the time of the

Protestant Reformation The Reformation (alternatively named the Protestant Reformation or the European Reformation) was a major movement within Western Christianity in 16th-century Europe that posed a religious and political challenge to the Catholic Church and in ...

Career

After studying

medicine Medicine is the science and Praxis (process), practice of caring for a patient, managing the diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, and Health promotion ...

for a time, Franz Aepinus devoted himself to the physical and mathematical sciences, in which he soon gained such distinction that he was admitted a member of the Prussian Academy of Sciences. In 1755, he was briefly the director of the Astronomisches Rechen-Institut. In 1757, he settled in St Petersburg as member of the

Russian Academy of Sciences The Russian Academy of Sciences (RAS; russian: Росси́йская акаде́мия нау́к (РАН) ''Rossíyskaya akadémiya naúk'') consists of the national academy of Russia; a network of scientific research institutes from across t ...

and professor of physics, and remained there till his retirement in 1798. The rest of his life was spent at Dorpat. He enjoyed the favor of Empress

Catherine II of Russia , en, Catherine Alexeievna Romanova, link=yes , house = , father = Christian August, Prince of Anhalt-Zerbst , mother = Joanna Elisabeth of Holstein-Gottorp , birth_date = , birth_name = Princess Sophie of Anha ...

, who appointed him tutor to her son Paul, and endeavoured, without success, to establish normal schools throughout the empire under his direction. In 1761, Aepinus was elected a foreign member of the Royal Swedish Academy of Sciences. In 1764, he was appointed as a head of the cryptographic service of Russia, and held this position till 1797, during 33 years.

Works

His principal work, ''Tentamen Theoriae Electricitatis et Magnetismi'' (An Attempt at a Theory of Electricity and Magnetism), published at St. Petersburg in 1759, was the first systematic attempt to apply mathematical reasoning to these subjects. He also published a treatise, in 1761, ''De Distributione Caloris per Tellurem'' (On the Distribution of Heat in the Earth), and he was the author of memoirs on different subjects in

astronomy Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...

mechanics Mechanics (from Ancient Greek: μηχανική, ''mēkhanikḗ'', "of machines") is the area of mathematics and physics concerned with the relationships between force, matter, and motion among physical objects. Forces applied to objects ...

optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultra ...

and pure mathematics, contained in the journals of the learned societies of St. Petersburg and

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. His discussion of the effects of parallax in the transit of a planet over the sun's disc excited great interest, having appeared (in 1764) between the dates of the two transits of

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...

that took place in the 18th century.

Electrical theories

Aepinus and Henry Cavendish devised theories of electricity which were essentially the same, yet had been framed without any communication between these two philosophers. Aepinus however published his theory about ten years before that of Cavendish. These are essentially modern theories which eventually put to rest the idea of two fluids. Their theories said that * ''... the electric fluid is a substance, the particles of which repel each other, and attract the particles of all other matter, with a force inversely as the square of distance.'' he square law was added later* ''The particles of all other matter also repel each other, and attract those of the electric fluid with a force varying according to the same law. Or, if we consider the electric fluid as matter different from all other matter, the particles of all matter, both those of the electric fluid, and of other matter, repel particles of the same kind, and attract those of a contrary kind, with a force inversely as the square of the distance.'' Cavendish and Aepinus believed that the electric fluid was * ''another sort of matter. ... Its weight in any body probably bears a very small proportion to the weight of the matter in the body, but yet the force with which the electric fluid in any body attracts any particle of matter in that body, must be equal to the force with which the matter of the body repels that particle, otherwise the body would appear electrical, as will afterwards appear.'' In effect, they are imagining the 'electric fluid' as consisting of electrons with almost no mass, but still with substantial electrical attractive and repulsive power. Static electricity then becomes a matter of a superabundance of electrons in one body, and a shortage of electrons in another.

References

External links

* Electricity entry i
Edinburgh Encyclopaedia
of 1832 * * {{DEFAULTSORT:Aepinus, Franz 1724 births 1802 deaths Burials at Raadi cemetery People from Rostock People from the Duchy of Mecklenburg-Schwerin Natural philosophers 18th-century German scientists 18th-century German mathematicians Scientists from Mecklenburg-Western Pomerania German emigrants to the Russian Empire Scientists from the Russian Empire Inventors from the Russian Empire 18th-century German inventors Members of the Prussian Academy of Sciences Full members of the Saint Petersburg Academy of Sciences Members of the Royal Swedish Academy of Sciences University of Jena alumni University of Rostock alumni Saint Petersburg State University faculty Members of the Göttingen Academy of Sciences and Humanities