AEPINUS, FRANZ ULRICH THEODOR German natural philosopher, was born at Rostock, Saxony, on Dec. 13 1724. In 1757 he settled in St. Petersburg as member of the imperial academy of sciences and professor of physics, and remained there till his retirement in 1798. The rest of his life was spent at Dorpat, where he died on Aug. 1o, 1802.
Aepinus is best known by his researches, theoretical and experi mental, in electricity and magnetism, and his principal work Tentamen Theoriae Electricitatis et Magnetismi, published at St. Petersburg in 1759, was the first systematic attempt to apply mathematical reasoning to these subjects. 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 that took place in the 18th century.