Rudjer Joseph Boscovich (Croatian Ruđer Josip Bošković, Руђер Јосип Бошковић; Italian Ruggero Giuseppe Boscovich, first name also sometimes spelled Roger in English) (May 18, 1711 – February 13, 1787), was a Jesuit, physicist, astronomer, mathematician, philosopher, diplomat and poet from Dubrovnik (or Ragusa, the previously frequently referred to Italian version).
He is famous for his atomic theory, given as a clear, precisely-formulated system utilizing principles of Newtonian mechanics. This work inspired Michael Faraday to develop field theory for electromagnetic interaction. Boscovich also gave many important contributions to astronomy, including the first geometric procedure for determining the equator of a rotating planet from three observations of a surface feature and for computing the orbit of a planet from three observations of its position.
Boscovich was born in Dubrovnik to Nikola Bošković and Paula Bettera. Dubrovnik was an independent republic at the time, and Ruđer Josip was the seventh child of a daughter of an Italic noble and a Slavic trader who immigrated from the hinterland, both Catholics. Boscovich's ethnicity is a controversial issue; some claim that he was an Italian because he was educated, lived and worked Italy, some that he was a Croat because he was born in a teritorry which is today a part of Croatia, and some that he was a Serb because his father, Nikola Bošković came from the Serb family Pokrajčići from the village of Orahov Do in eastern Herzegovina.
When Rudjer was ten, his father died. In his fifteenth year, after passing through the usual elementary studies, he entered the Society of Jesus. On completing his novitiate, which was spent at Rome, he studied mathematics and physics at the Collegium Romanum; and so brilliant was his progress in these sciences that in 1740 he was appointed professor of mathematics in the college.
He was especially appropriate for this post due to his acquaintance with recent advances in science, and his skill in a classical severity of demonstration, acquired by a thorough study of the works of the Greek geometricians. Several years before this appointment he had made a name for himself with an elegant solution of the problem of finding the Sun's equator and determining the period of its rotation by observation of the spots on its surface.
Notwithstanding the arduous duties of his professorship, he found time for investigation in all the fields of physical science, and he published a very large number of dissertations, some of them of considerable length. Among subjects were the transit of Mercury, the Aurora Borealis (corona), the figure of the Earth, the observation of the fixed stars, the inequalities in terrestrial gravitation, the application of mathematics to the theory of the telescope, the limits of certainty in astronomical observations, the solid of greatest attraction, the cycloid, the logistic curve, the theory of comets, the tides, the law of continuity, the double refraction micrometer, various problems of spherical trigonometry. In 1742 he was consulted, with other men of science, by the Pope Benedict XIV, as to the best means of securing the stability of the dome of St. Peter's, Rome, in which a crack had been discovered. His suggestion was adopted.
He agreed to be part in the Portuguese expedition for the survey of Brazil and the measurement of a degree of the meridian, but was persuaded by the Pope to stay in Italy and to undertake a similar task there. Accordingly, in conjunction with Christopher Maire, an English Jesuit who measured an arc of two degrees between Rome and Rimini. The operation begun at the end of 1750, and was completed in about two years. An account of them was published in 1755, under the name De Litteraria expeditione per pontificiam ditionem ad dimetiendos duos meridiani gradus a PP. Maire et Boscovicli. The value of this work was increased by a carefully prepared map of the States of the Church. A French translation appeared in 1770. A dispute arised between the grand duke of Tuscany and the republic of Lucca with respect to the drainage of a lake. As agent of Lucca, Boscovich was sent, in 1757 to Vienna and succeeded in bringing satisfactory arrangement of the matter.
In Vienna in 1758, he published famous work, Theoria philosophiae naturalis redacta ad unicam legem virium in natura existentium (Theory of Natural philosophy derived to the single Law of forces, which exist in Nature), containing his atomic theory and his theory of forces. Second edition was published in 1763 in Venice, the third in 1922 in London, the fourth in in 1966 in United States. Fifth in Zagreb in 1974.
Another occasion to exercise of his diplomatic ability soon arised. Suspicion was brought up by British government that warships had been outfitted in the port of Dubrovnik for the service of France, that the neutrality of Dubrovnik today has been violated. Boscovich was selected to undertake an ambassadorship to London (1760), to vindicate the character of his native place and satisfy the government. This mission he discharged successfully — a credit to him and a delight to his countrymen. During his stay in England he was elected a fellow of the Royal Society.
In 1761 astronomers were preparing to observe the transit of Venus across the Sun's disc. Under the influence of Royal Society Boscovich decided to travel to Istanbul - Carigrad. He came late and he returned over Bulgaria and Moldavia to Poland. Wanted to proceed to Saint Petersburg where was elected as a member of Russian Academy of Sciences. Ill health compelled him soon to return to Italy. In 1764 he was called to serve as the chair of mathematics at the university of Pavia, and he held this post with the directorship of Brera near Milan observatory, for six years.
He was invited by the Royal Society of London to undertake an expedition to California to observe the transit of Venus in 1769 again, but this was prevented by the recent decree of the Spanish government of the expulsion of the Jesuits from its dominions. Boscovich had many enemies and he was driven to frequent change of residence. About 1777 he returned to Milan, where he kept teaching and directing the Brera observatory. Deprived of past and intrigues of his associates, he was about to retire to Dubrovnik when in 1773, the news of the suppression of his order in Italy reched him. Uncertainty led him to accept an invitation from the King of France to come to Paris where he was appointed director of optics for the navy, with a pension of 8000 "livres" and position created for him. He naturalized and stayed ten years, but position became irksome, and at length intolerable. He however, continued to work to the pursuits of science, and published many remarkable works. Among them were an elegant solution of the problem to determine the orbit of a comet from three observations, works on micrometer and achromatic telescopes. In 1783 he returned to Italy, and spent two years at Bassano, occupying himself with the publication of his Opera pertinentia ad opticam et astronomiam, etc., published in 1785 in five volumes quarto. After a visit of some months to the convent of Vallombrosa, he went to Brera in 1786 and resumed his literary labours. At that time his health was failing, reputation was on the wane, works did not sell, and he gradually fell prey to illness and disappointment. He died in Milan and was buried in the church St. Maria Podone.
In addition to the works already mentioned Boscovich published Elementa universae matheseos (1754), the substance of the course of study prepared for his pupils, and a narrative of his travels, entitled Giornale di un viaggio da Constantinopoli in Polonia (A diary of the journey from Constantinople to Poland) (1762), of which several editions and a French translation appeared.
The Institute of Theoretical Physics in Zagreb, founded in 1950 bears his name upon the proposal of physicist Ivan Supek. The Astronomical Society in Belgrade and a crater on the Moon also bear his name.