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Auzout considers Giovanni Domenico Cassini's hypothesis about calculating the direction of the comet in 1664-1665 and explains his own calculations for the comet's motion from January to March. Signor Magolotti's observations are also given. Auzout says that he will explain his hypothesis in full shortly. A note by Auzout, dated 13 March 1665, states that he has added a sketch of the head of Aries where the majority of the stars are. No sketch is present. Henry Oldenburg annotated this letter: 'An extract of M. Auzout's letter concerning Cassini's Hypothesis of Comets, imparted to M. Oldenburg for the R. Society. Read April 19 1665. Entd. L.B.1. p.245.'

Subject: Astronomy

Read 19 April 1665.
Partial translation printed in 'Philosophical Transactions', vol 1, no 2, pp 18-20.

Reference number
Earliest possible date
03 March 1665
Physical description
Ink on paper
Page extent
7 pages

Creator name

Adrian Auzout

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Adrian Auzout, Letter, from Adrian Auzout to [unknown correspondent], 03 March 1665, EL/A/1, The Royal Society Archives, London,, accessed on 18 May 2024

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  • Early Letters

    Dates: 1613-1740

    The archival collection known as 'Early Letters' is composed of original manuscript letters sent to, or collected by, the Royal Society from English and foreign correspondents.

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