In the 1720s two Jesuit astronomers working at the court of King João V of Portugal, in Lisbon, received several instruments produced by the best makers in London, Paris and Rome. With the crucial help of the Portuguese diplomatic network contacts with academies, savants and instrument makers were established, seeking technical advice and the best astronomical instruments available at the time. It was in this context that in April 1726 a set of Latin instructions accompanying pendulum clocks made by George (...) Graham were dispatched from London to Lisbon. These unpublished instructions are now preserved in the papers of Giovanni Battista Carbone, one of these Jesuit astronomers, offering a significant window into the procedures and technical details involved in the setting, operation and transport of Graham’s astronomical clocks. In this paper, I will not only discuss this important document in the framework of Graham’s contributions to astronomy and horology, but also in the perspective of the search for accuracy. (shrink)

ABSTRACTIt is known that throughout the seventeenth century the world system proposed by Tycho Brahe assumed a preponderant position in the Iberian cosmological debate, according to many opinions the one showing the best agreement to empirical evidence. Moreover, the Tychonian model did not present the difficulties of apparent contradiction with scriptures, as the heliocentric system of Nicolaus Copernicus did, since it kept the earth fixed at the centre of the world. However, Tycho, as a Lutheran author, was targeted by the (...) Inquisition. Passages of various works of the Danish astronomer were included in the Spanish Indices of 1632, 1640 and 1707, although the formal condemnation of the Roman Inquisition never materialized. In the network of the Society of Jesus a seemingly informal censorship also circulated, apparently based on Tridentine determinations, published in 1651 in the influential work of Giambattista Riccioli Almagestum novum. In this paper I will discuss the scope, effects and limitations of the censorship of Tycho's scientific books in Portugal and Spain, through the analysis of several annotated copies, preserved manly in Iberian libraries, with a special attention to books with a well-established provenance in past Jesuit colleges. (shrink)