Almagestum Novum astronomiam veterem novamque complectens observationibus aliorum, et propriis novisque theorematibus, problematibus, ac tabulis promotam, in tres tomos distributam quorum argumentum sequens pagina explicabit.

Bologna: heirs of Vittorio Benacci, 1651.

First edition of Riccioli's ‘New Almagest’, his attempt at a comprehensive non-Copernican account of the heavens that would excel in detail and accuracy all previous models and reconcile theology with observational astronomy. Divided into ten books, this work was one of the greatest productions of Jesuit science in the seventeenth century, and encompasses a great deal of experimental physics besides observational and theoretical astronomy. Riccioli’s “commitment to church doctrine brought him into conflict with the ideas expressed by Galileo and his students and by the Florentine Accademia del Cimento … Following the Inquisition’s condemnation of Galileo’s astronomical theories, for example, Riccioli became one of the most ardent opponents of the Copernican system, which he tried to refute in every way. He nonetheless recognized the simplicity and the imaginative force of the Copernican theory, and acknowledged it as the best ‘mathematical hypothesis’, while striving to divorce it from any effective notion of truth. In particular, Riccioli designed a series of experiments by which he hoped to disprove Galileo’s conclusions, but instead ratified them. This is especially true of his accurate and ingenious investigations of falling bodies … With his fellow Jesuit, Francesco Maria Grimaldi, Riccioli succeeded in perfecting the pendulum as an instrument to measure time, thereby surpassing Galileo and his school and laying the groundwork for a number of important later applications” (DSB). These experiments are all contained in the Almagestum novum. “He observed the topography of the moon and, in concert with Grimaldi, introduced some of the nomenclature that is still used to describe lunar features. Riccioli described sunspots, compiled star catalogues, and recorded his observation of a double star; he also noted the colored bands parallel to the equator of Jupiter and made observations of Saturn that, if he had had better instruments, might have led him to recognize its rings” (ibid.). This work also contains the full text of the Inquisition’s trial of Galileo and of his abjuration. “For his map of the moon (drawn by fellow Jesuit Grimaldi) he proposed naming the lunar features after astronomers. The names of many of the Jesuits in this exhibit may be found at the bottom, clustered around the prominent crater of Tycho. Galileo was cast adrift, with Copernicus and Kepler, in the ‘Sea of Storms’ to the West” (Jesuit science in the age of Galileo, n. 21). ABPC/RBH record the sale of four copies since Norman: Christie’s, July 9, 2019, lot 325, £7,500 ($9,479); Swann, June 1, 2014, lot 164, $8,125; Alde, June 1, 2011, lot 174, €6,000 ($8,656); Christie’s New York, April 17, 2007, lot 436, $90,000, the last being John Flamsteed’s copy.

Giovanni Battista Riccioli (1598-1671) was ordained as a Jesuit priest in 1628. Riccioli’s interest in astronomy developed during his studies of philosophy and theology at the College of Palma. After the condemnation of Galileo in 1633, he was responsible for defending the Church’s position denying the motion of the earth.

“In 1640 Riccioli began work on a project that had long captured his interest: a compendium summarizing the whole of ancient and contemporary astronomy. Given his solidly Aristotelian education in natural philosophy and theology as well as his early training and collaboration with a group of experimentally-minded Jesuits based in Parma and Bologna, Riccioli was an ideal candidate to navigate the turbulent waters of early seventeenth-century astronomy. In preparation for his task, Riccioli read widely, consulting the texts of established authorities as well as those of more recent innovators, many of whom were also among his personal correspondents; these included Johannes Kepler, Johannes Hevelius and Giovanni Domenico Cassini. Wanting to go beyond the standard works held in the library of his own college in Parma, Riccioli persuaded his superiors to send him to Bologna, where more specialized scholarship on mathematics and astronomy was available. Riccioli applied himself boldly to sensitive topics, gaining access to documents relating to the Church’s 1616 and 1633 decisions regarding Copernicanism and obtaining special permission from his superiors to read Galileo’s Dialogo of 1632. Not content to rely entirely on the reported experiences of others, Riccioli made his own astronomical observations and conducted mechanical and optical experiments. His efforts were facilitated by the astronomical observatory he built at the College of St Lucia in Bologna, which, according to unpublished Jesuit records, housed many astronomical instruments and was frequented by foreign savants.

“The result was Riccioli’s magisterial Almagestum novum, a work published in Bologna after six years of negotiations with the Jesuit order’s internal censors. Treating a variety of topics central to traditional teaching on astronomy and cosmology, including the sphere and its circles, the motion and qualities of the Sun, Moon, and other planets, and the world systems, the work integrated recent novelties and controversies into a more basic and standard treatment of the material. It quickly became a text that no serious seventeenth-century astronomer could do without. John Flamsteed, for example, the Astronomer Royal of England and both a Copernican and a Protestant, relied upon it for much of the information in the lectures on astronomy he gave in the 1680s” (Raphael, pp. 73-76).

One of the main themes of the work is of course an analysis of the case for and against the Copernican hypothesis. Riccioli’s analysis “hinged on two key arguments – both scientific in nature, both difficult to refute at the time, and both destined to be matters of scientific investigation into the nineteenth century, long after the debate over the world system hypothesis was settled. Riccioli’s work illustrates an interesting aspect to that debate: that the geocentric hypothesis, in the form advocated by Tycho Brahe, was backed by real and strong arguments in 1651.

“Riccioli discusses 126 arguments in his analysis: 49 pro-Copernican, 77 anti-Copernican. For each argument Riccioli provides the opposing side’s response to that argument, if he believes a valid response exists, as is usually the case. Thus, while Riccioli does note the issue of birds keeping pace with a moving Earth as an anti-Copernican argument, he also notes that there is a simple response to this argument – that the Erath, the birds, and the air all share a common motion. Thus, Riccioli is not presenting the birds issue as an argument having real weight, but simply as an argument that he been proffered in the world system debate.

“Such is the case with those arguments Riccioli presents that relate to matters of theology, scripture, or religious authority. Perhaps surprisingly, only two of the 126 arguments relate to such matters …

“What Riccioli believes does win the debate are certain key arguments to which there are no valid responses. First among these is an argument based on the physical sizes of stars; the second in an argument based on the lack of detectable effects, caused by the supposed rotation of the Earth, in the motions of projectiles and falling bodies.

“The star size argument in the Almagestum novum is based on the idea noted by Galileo that, just as the telescope reveals the true size and crescent shape of Venus which the naked eye does not see, it also reveals the true size and global shape of a fixed star. The argument was that for a star to have such a telescopic appearance, and also to lie at the distance required to explain the absence of detectable annual parallax in the stars under the Copernican hypothesis, basic geometry required the star to be absurdly immense – comparable to the size of the Earth’s orbit, and thus orders of magnitude larger than even the Sun … whereas in a geocentric hypothesis the fixed stars would lie just beyond the orbit of Saturn and be of reasonable size. Moreover, says Riccioli, the only answer the Copernicans have to the star size argument is to appeal to the power of God [who could create stars as large as he wished]. And such was indeed the Copernican answer … The true answer to the star size argument (that the ‘globes’ of stars seen in small telescopes are completely spurious and that actually stars are nearly dimensionless points of light – entirely consistent with their being Sun-sized bodies at Copernican distance) would begin to be uncovered in the decades following the Almagestum novum but would not be fully untangled until the nineteenth century.

“While Riccioli gives much weight to the star size argument, it is not the only one to which he believes the Copernicans have no valid response: there is also the argument based on the lack of detectable effects, caused the supposed rotation of the Earth, in the motions of projectiles and falling bodies. Galileo had used the analogy of motion on board a moving ship to argue that no experiment on Earth’s surface could detect Earth’s motion … However, the analogy is flawed, for the surface of the Earth is not a translating flat frame of reference like the hypothetical ship, but a rotating spherical frame of reference. The Earth’s rotation therefore does reveal itself, in particular in slight deflections in projectiles and falling bodies. Riccioli (and his fellow-Jesuit Francesco Grimaldi, to whom Riccioli credits much of the work concerning these ideas) recognized that these effects should exist. For example, they argued that if Earth rotated, a cannonball launched northward should deflect slightly eastward during its flight (enough, they thought, to be detected by the most skilled artillerymen of the day), and a heavy weight dropped from a fixed point high above the Earth should deflect eastward as it falls.

“These arguments are valid – the effects Riccioli and Grimaldi describe do occur and would be thoroughly investigated by physicists in the nineteenth century. Riccioli acknowledges a possibility that sufficient experiments might not have been done to truly detect such effects, but Isaac Newton himself would argue a few decades later that the easterly deflection of a falling weight ought to be detectable by a straightforward experiment. But both Riccioli and Newton would certainly have been surprised by just how difficult such effects are to detect, thanks to aspects of physics that would not be fully understood until centuries after the Almagestum novum” (Graney, ‘Science Rather than God’, pp. 215-219). The discussion by Riccioli and Grimaldi of these effects has been seen as an anticipation of the discovery of the Coriolis effect.

Riccioli did not just theorize about falling bodies, he also carried out experiments. “His experiments, which for the most part vindicated Galileo’s theory, have come to be regarded by historians as the first precise measurements of g [the acceleration due to gravity] … Riccioli’s report is found in his encyclopedic 1651 treatise Almagestum novum … Riccioli opens his report with a review of common experiences and literary anecdotes that support the notion of an acceleration due to gravity … Next, Riccioli gets down to the business at hand, ‘the measuring of the space which any heavy body traverses in natural descent during equal time intervals.’ He describes the experiment in exquisite detail … Riccioli then describes the various locations used for the experiment, giving special attention to the Asinelli Tower … In the end, the experiment largely vindicated Galileo’s ideas about falling bodies. Riccioli’s data show that a ball falls 15 Roman feet (Rmft) in one second, 60 Rmft in two seconds, 135 Rmft in three seconds, and so on – the distance increases as time squared. Riccioli himself did not calculate g per se, but a fit of his data to the appropriate free-fall equation yields g = 29.8 ± 0.7 Rmft/s2. Modern-day measurements show that the Asinelli Tower – described by Riccioli as having a height of 312 Rmft – stands at 98.37 m, so Riccioli’s Roman foot was probably close to 0.301 m. His g, then, would translate to 9.36 ± 0.22 m/s2, about 5% off from today’s accepted value, g = 9.8 m/s2 … Riccioli also calculated the incremental distances traveled by a falling body for successive, regular time intervals. That distance, the average velocity in a given interval, grew linearly with time, following the same sequence of odd numbers that had been prescribed by Galileo – the ball falls one unit distance in the first unit of time, three in the second, five in the third, and so forth. The pattern was remarkably consistent – and, to Riccioli, remarkably surprising. His own expectation had been that velocity should grow not linearly but exponentially, a misconception that he addresses frankly in Almagestum novumhaving found Galileo to be right,

‘Fr. Grimaldi and I went to talk to the distinguished Professor of Mathematics at the Bologna University, Fr. Bonaventure Cavalieri, who was at one time a protégé of Galileo. I told him about the agreement of my experiments with the experiments of Galileo, at least as far as this proportion. Fr. Cavalieri was confined by arthritis and gout to a bed, or to a little chair; he was not able to take part in the experiments. However it was incredible how greatly he was exhilarated because of our testimony.’



One vol. (all published) in two parts bound in two, folio (357 x 245 mm), pp. [xii, including frontispiece], xlvii, [1 blank], 204 [15, i.e., 204-211 numbered in halves], 212-763, [1]; [vi including frontispiece], xviii, 675, [1], with two engraved frontispieces, engraved arms on dedication leaf and second title, printer’s device with motto ‘Fluctibus et fremitu assurgens benace marino’ on final leaf recto of part 1 and on final leaf verso of part 2, two double-page engraved lunar maps; and numerous woodcut illustrations and diagrams throughout (occasional light browning). Nineteenth-century vellum, spine gilt with contrasting orange and green lettering-pieces.

Item #5123

Price: $32,000.00

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