Maximilianus Hell (1720-1792) - Munin

II.2.1 THE ROLE OF SWEDEN IN THE VENUS TRANSIT PROJECTS,
1761 AND 1769
The author of the „History of Astronomy in Sweden‟, N. V. E. Nordenmark, has carried out
thorough research on Swedish eighteenth-century astronomy and its main protagonists. 9
According to his studies, Swedish astronomy was integrated in the international, astronomical
community by Anders (Andreas) Celsius (1701–1744), who was named Professor of
Astronomy at Uppsala in 1730. Shortly afterwards, Celsius embarked upon a four-year
journey through Germany, Italy, France and England, where he visited the main centres of
learning and was elected a member of various academies and scientific societies. He then
joined Pierre Louis Moreau de Maupertuis (1698–1759) on his famous 1736-1737 expedition
to Lapland and appears to have been instrumental in persuading Maupertuis to opt for the
Swedish Tornedal valley instead of northern Norway or Iceland for his longitudinal
measurements. 10 As a result of this expedition, the Earth was proven to be flattened near the
poles, not stretched, as the Cartesians had thought. 11
The process of integrating Swedish astronomy within the Republic of Letters was continued
by the next generation of astronomers, of whom Pehr (Petrus) Wilhelm Wargentin (1717–
1783) merits particular mention. His thesis „On the Moons of Jupiter‟ (De Satellitibus Jovis),
supported under the presidency of Celsius in 1741, marked the start of what was to become a
main activity throughout his career: diligent observations and theoretical work on the moons
of Jupiter. The accuracy of Wargentin‟s observations made them useful for longitude
determinations of numerous sites abroad. Even more importantly, Wargentin was also the
secretary of the Royal Swedish Academy of Sciences from 1749 until his death in 1783, and
corresponded with influential representatives of the entire Republic of Letters. Wargentin was
to become heavily involved in the international effort to determine the parallaxes of the
Moon, Mars and Venus in the early 1750s, when the Académie Royale des Sciences in Paris
sent the astronomer Lacaille to the Cape of Good Hope and collaborated with colleagues in
Germany, Italy and Sweden in order to obtain corresponding observations from roughly the
9 For this section I have used Nordenmark, Astronomiens historia i Sverige inntil år 1800, Uppsala 1959 and the
same author‟s Pehr Wilhelm Wargentin …, Uppsala 1939. Nordenmark has also written monographs on other
Swedish eighteenth-century astronomers. His mastery of Latin, German, French and English, aside from
Swedish, combined with a magisterial use of archival as well as library sources, render his studies indispensable.
Other major studies of the history of Swedish astronomy in the period have been made by Lindroth and
Widmalm; see also Sinnerstad 1989 and the works of Pihlaja (cf. Section I.1.1.3 above).
10 For a survey of the life and career of Celsius, see Nordenmark 1959, pp. 158-191.
11 See for example Terrall 1992. When Maupertuis came under attack for his theory, Celsius was one of those
who went into the field to defend his findings, cf. Nordenmark 1959, pp. 174-176.
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