Daniel Melanderhjelm

Daniel Melander, knighted Melanderhjelm, (29 October 1726 – 8 January 1810) was a Swedish mathematician and astronomer, professor and rector of Uppsala University, secretary of the Royal Swedish Academy of Sciences and councillor (Swedish: kansliråd).

Biography Daniel Melander's father Simon Melander was a school headmaster in Stockholm and vicar In 1801 he received the title of councillor (kansliråds). Melanderhjelm was a member of the Royal Society of Sciences in Uppsala, the Academy of Sciences (1765), the Royal Swedish Academy of Letters, History and Antiquities (1780) and the Royal Swedish Academy of War Sciences.

He was married to his cousin Margaretha Katarina Frondin, daughter of chamber councillor Professor Elias Frondin and Gunilla Rommel, and sister of Berge Frondin. He survived both his wife and children, so that his family line ended in 1810. He is buried in Uppsala Cathedral.

Work as astronomer Melanderhjelm published widely on astronomy. To support academic teaching, he published Conspectus praelectionum academicarum continens fundamenta astronomiae (1779), which was later published in a somewhat revised and expanded form in Swedish under the title Astronomie (1795). Its Latin edition was also used abroad well into the 19th century. His more scientific works were mainly on celestial mechanics, especially the general theory of the Solar System and Lunar theory.

In Om den synliga verldens större eller mindre varaktighet (on the greater or lesser duration of the visible world, 1771–1772), Melanderhjelm tried to show that among all possible laws of attraction the actually existing one is the most suitable for the existence of the world system. Among his works on the theory of the Moon was De theoria lunae commentarii (1769), in which, with the theory of gravitation as a starting point, the motion of the Moon is determined, and related problems are solved according to other, partly simpler, methods than those given by Clairaut, Euler and Lagrange. Among the subjects of his other writings are transits of Venus, the atmospheres of the planets and the method of determining the equation of time. Melanderhjelm also initiated the 1802 meridian survey in Lapland and wrote the foreword to the account thereof.

Work as mathematician Melanderhjelm also wrote several works on pure mathematics. He also tried to support academic teaching in this area and to this end published a new edition of Newton's work on the quadrature of curves, which he provided with notes and additions. In addition, he wrote on integral calculus and the theory for the integration of differential equations; however, his results were somewhat specific and contained only fairly simple substitution formulas.

Melanderhjelm on literary subjects wrote, for example Om nyttan af ett eget de lärdes språk (on the benefit of one's own language).