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Mapping the New World

Eighteenth century astronomers determined latitudes in the Amazon and wrote about the region

National LibraryMap of the territorial boundaries map, from 1749, made for the Treaty of Madrid. The red line shows how the location of territorial boundaries according to the Treaty of TordesillasNational Library

At a time when South America was still a collection of Hispanic and Portuguese colonies, Don Fernando VI of Spain and Dom João V of Portugal signed the Treaty of Madrid to define boundaries and put an end to the territorial disputes that were so commonplace in 1750. For this purpose it was necessary to demarcate land based on the actual territorial occupation by settlers of both nations in South America, as the Treaty of Tordesillas, signed in 1494, had since become a dead old document. To create maps and define the natural boundaries of land possessions in the Iberian Peninsula, the Portuguese government created the first Commission for Border Delimitation with engineers, cartographers, astronomers and a “scribe” (drawer). The astronomers were two “mathematician priests”, as they were known at the time: the Croatian Jesuit Priest, Ignác Szentmártonyi, and the Italian secular Presbyterian Priest, Giovanni Angelo Brunelli. Both men worked on the committee that oversaw the Brazilian Amazon effort and contributed not only to taking measurements, but also with reports that tried to separate fantasy from reason and explain the uses and customs of the land.

Giovanni Brunelli (1722-1804) came from the Astronomy Observatory of the Science Academy at the Bologna Institute and arrived in Belém in August 1753 with the other members of the commission. In 1754, the expedition set out from Belém in three parties to conduct the demarcation and reconvene in Mariuá (modern day Braga), on the Rio Negro. They were led by the governor of Pará (Greater Pará) Maranhão, Francisco Xavier de Mendonça Furtado, half brother of Sebastião José de Carvalho e Melo, the Marquis of Pombal and then Secretary of State for Dom José I. The trip took 88 days. In Mariuá the commission waited in vain for the arrival of the Spaniard contingent until 1758, when they finally returned to Belém. The meeting had been arranged to settle the boundaries of the colonial territories of the two kingdoms.

Brunelli stayed in the Amazon until 1761. In the eight years that he spent in the region, Brunelli wrote three epistolary reports. In 2010, Nelson Papavero, of the Zoology Museum of University of São Paulo, Nelson Sanjad and William Leslie Overal, of the Emilio Goeldi Museum of Pará (MPEG), Abner Chiquieri of the Rural Federal University of Rio de Janeiro, and Riccardo Mugnai of the Oswaldo Cruz Foundation, translated these memoirs into Portuguese for the first time and published them in the May-August edition of the Boletim de Ciências Humanas do MPEG (Bulletin of the Humanities). “That of Brunelli is the oldest known reference to the candiru, a very small fish that is widely feared in the Amazon region because it is believed that, sometimes, the fish enters the urethra of those who bathe in the Rivers,” according to the zoologist, Papavero. The account appeared in About the Amazon River, which was published in Italy in 1791.

Brunelli’s two other texts call for careful attention to the description and try to explain something that seemed mysterious. In the first case, On Manioc, published in 1767, he details techniques of the planting, manufacture and consumption of manioc by indigenous communities and other, more recent settlers in the Amazon. “It has the appearance of a formal work in ethnography. The report on the use of this root is innovative and very accurate, “says Nelson Sanjad, a researcher of the history of science at the Goeldi Museum. “He shows no disdain or prejudice and remarks several times that the manioc flour, for example, is quite tasty.” In the second case, On Pororoca, which also came out in 1767, the Italian remarked on how impressed he was with the pororoca wave phenomenon that occurs in some areas of the mouth of the Amazon and Tocantins Rivers a few times a year and does not conform to the fanciful explanations of the time. By means of observation, he attempts to interpret what is happening, but also errs in conclusion: to him, the pororoca wave must have its origin in the underground channels through which water must flow in and out, in huge volumes and with great physical force. This was one of the first attempts to explain the natural phenomenon in the light of reason, when there was still no knowledge or understanding of the complex hydrology of the region.

The astronomer and cartographer, Szentmártonyi (1718-1793), had a much more challenging life than the Italian due to political issues. When Pombal ordered the expulsion of Jesuits from all over the kingdom in 1759, he was arrested in Belém and remained imprisoned in Portugal for 18 years. During his time in the Amazon, he determined the longitude of Belém, made astronomical observations for the hydrographic map of parts of the Amazon and Negro Rivers, worked on the latitudes and longitudes for a series of charts taken from the cities and Riverside villages and wrote an account of indigenous tribes from the Negro and Orinoco Rivers.

The effort to discern the certainty of the probable and the improbable of these astronomers – in particular what appears in the writings of Brunelli – is seen in several reports by the naturalists who described the Amazon region until the nineteenth century. “This is one of the characteristics of scientific and literary history related to the region,” says Nelson Sanjad.