The Petersburg Academy of Sciences as Seen by the Finnish Mathematician Anders Johan Lexell

The life of the Finnish mathematician Anders Johan Lexell (1740–1784) offers an interesting example of internationalisation of the sciences in the 18th century. Born and educated in Åbo (Turku), Finland, then a part of Sweden, he became a lecturer at the local university, visited Uppsala briefly, but due to lack of prospects for an academic career, he decided to move to nearby St. Petersburg, Russia, to make use of his talents at the Imperial Academy of Sciences. There, starting in 1768, he became a close associate of the leading mathematician of the era, Leonhard Euler. Moreover, he corresponded assiduously with Swedish scientists, including Carl Linnaeus, in all areas of science. We show in this article that his correspondence provides plenty of information about the Republic of Letters and, in particular, the Russo-Swedish scientific relations of the day.