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Records of a comet

Mathematician wrote a manuscript about Halley's passage across the skies of Brazil 252 years ago

NASAHalley seen in 1986 on its return after 76 yearsNASA

The idea of Brazil as a colony without any contact with natural (or scientific, as it has been called since the nineteenth century) knowledge is a notion that historians now appear to have put behind them. Documents found in the last few decades indicate that there were always people writing in as objective a way as possible about Brazilian plants and animals, recording the movements of the stars in the skies of the southern hemisphere and studying mathematics and minerals in a way that was similar to that being done in Europe. There were only a few of these scientists from the past who lived here and they were almost always foreigners, but they existed. In the seventeenth century, George Marcgrave in Recife and Valentin Stansel in Salvador published work that was admired and cited in Europe. In the eighteenth century Portuguese Jesuit, José Monteiro da Rocha (1734-1819), followed this same path and in 1759 wrote the manuscript, “The Physical and Mathematical System of the Comets”, after having observed a comet in Salvador where he was living. It was the famous Halley’s Comet, which English astronomer, Edmond Halley, predicted would be visible from Earth every 76 years.

Monteiro was from Vila de Canavezes and came to Brazil when he was still a child, brought here by a missionary from the Company of Jesus. In the College of Salvador, he was ordained a priest and enjoyed a good education in mathematics, a mark of the Jesuits of that time, and had access to a library containing the latest books, with works by Newton, Copernicus, Descartes and Gassendi. Thanks to his active correspondence, he knew that Halley’s Comet was likely to return and be seen at the end of 1758. However, he had no access to the work of Frenchman, Alexis-Claude Clairaut, who made more accurate calculations at the beginning of that same year and concluded that the comet would return a month later than predicted, i.e. at the beginning of 1759. Monteiro actually saw it for the first time on March 20 and made his final observations at the end of April. As he did not have Clairaut’s information he failed to note that it was Halley’s Comet.

As a consequence of these observations he wrote “The Physical and Mathematical System of the Comets”, probably also in 1759, and sent the manuscript to Portugal. Monteiro was 25 years old at the time. In that same year the Marquis of Pombal,  title of Minister Sebastião José de Carvalho e Melo, banned the Company of Jesus from everywhere in Portugal, but gave them the option to renounce the order as an alternative to exile. The young priest decided to stay in Salvador and became a secular priest and a public teacher of Latin and rhetoric. In the mid-1760s he returned to the land of his birth to continue studying.

He went to the University of Coimbra and there made a career for himself as a mathematician and astronomer. His penchant for the sciences led to him being invited to organize the new school of mathematics that was created by the Pombal reform of 1772 at the same university, where he became responsible for the chairs of mechanics and hydrodynamics, and subsequently for the chair of astronomy. In 1795 he was appointed the first director of the Portuguese Astronomical Observatory.

The manuscript written by the young Monteiro da Rocha deals with the physical nature of comets and calculation of the ephemerides, based on Newton’s theory of gravity and using a set of geometrical techniques. The text remained unpublished until 1998, when historian Carlos Ziller Camenietzki, from the Federal University of Rio de Janeiro, discovered it while on a working visit to the Évora Public Library, Portugal. “I asked them to microfilm it, I satisfied myself as to its originality and authenticity and managed to get it published in Brazil,” Ziller recounts. The book came out in 2000, published by the Museum of Astronomy and Like Sciences (Mast/MCT), in Rio de Janeiro. “Unfortunately it was not possible to track the paths that had led the manuscript being forgotten for more than 200 years.”

The historian is conscious of the fact that Monteiro’s treatise on astronomy is also rich in information about colonial culture and the erudite activities of the period. “These aspects are still not given much value,”  he says. According to mathematician, Ubiratan D’Ambrósio, professor emeritus at the State University of Campinas (Unicamp), whom Ziller first consulted on the importance of the religious man at that time, Monteiro was a good mathematician and an influential teacher in Portugal. “But his talent lay in astronomy, where he produced his most relevant work,” he concludes.