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Original scientific paper

Gradić’s Contacts with Some Scientists of His Time and His Correspondence with the French Astronomer Ismäel Boulliau

Stjepan Krasić

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page 119-133

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The article deals with the scientific works of Stjepan Gradić (1613—1683), diplomatic representative of the Dubrovnik Republic at the St. Peter's Chair and the erudite Director of the Vatican Library, particularly with his works in mathematics, physics, astronomy and optics. A distinctive attention has been paid to his scientific links with eminent scientists, his contemporaries, such as V. Viviani, B. Castelli, B. Cavalieri, M. Ricci, N. Steensen, G. A. Borelli, A. Auzout, Ch. Huygens and others. Very intensive correspondence was that with the French astronomer Ismäel Boulliau (1605-1694), with whom Gradić exchanged more, letters
(1664-1667) of which only six have been preserved. At the beginning they dealt with inquiries about some manuscript preserved in Parisian libraries, on the historical or scientific themes. Later their contents extended to the problems that the Italian mathematician Michelangelo Ricci (1619-1682) brought to light in his work »Geometrica Exercitatio« (Rome, 1666). As Gradić took part in writing it, Ricci devoted it to him accordingly. Gradić asked Boulliau, Adrien Auzout (1622-1691) and Christian Huygens (1629-1695) to send him their remarks and comments on that work. Unfortunately, this rich correspondence was unexpectedly interrupted because of the terrible earthquake that hit Dubrovnik on the 6th April 1667. Gradić dedicated all his efforts and time to the city reconstruction and defense from outside enemies.
The author supplies his work with four letters copied at the Vatican and National Library in Paris: two Gradić’s letters to Boulliau and two Boulliau's written to Gradić.


Stjepan Gradić, Ismäel Boulliau, letters

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