Estevão Cabral, 1795
Estevão Cabral (1734-1811) was a Portuguese priest and mathematician. He studied at a Jesuit college located in Coimbra, becoming a member of the Society of Jesus in 1750. Due to Pombal’s decree expelling all Jesuit from Portugal, the Jesuit college was closed and all of them had to move to Italy. Cabral went to Rome, to the Roman college and dedicated himself to mathematics. In 1771, after becoming a priest (1767) and teaching mathematics (1770) he published his first treatise entitled Elementa praecipua Euclidis geometriae planae ac solidae ex conicis etiam, ac sphaericis sectionibus collecta, faciliorique methodo demonstrata. Accedunt Arithemicae et Algebrae. Thereafter, he published a number of further important works, such as: Delle ville e de’ piú notabili monumenti antichi della cita’, e del territorio di Tivoli (1779), Ragioni per ispiegare, e riparare i danni del fiume Nera (1784), Ricerche istoriche, fisiche ed idrostatiche sopra la caduta del Velino nella Nera, colla dichiarazione di um nuovo metodo per determinare la velocità e la quantità delle Acque Correnti ed altro nuovo metodo de elevare l’Acqua ne’ Sifoni a grande alteza (1786). Considering his considerable scientific output, he was considered one of the most renowned and experienced Portuguese expert on hydraulics.
Estevão returned to Portugal in 1788 and began working with the Crown on problems related to river control and flow regulation. During his time in Portugal, he joined the Royal Academy of Sciences and he published the Tractado de Agrimensura. It is a treatise on land surveying for training land surveyors, that is divided into sixteen chapters and twenty-two propositions with two final pages of illustrations.
Cabral’s treatise can be found at the Portuguese National Library (BNP) in Lisbon.