Riccioli, John Baptist

, a learned Italian astronomer, philosopher, and mathematician, was born in 1598, at Ferrara, a city in Italy, in the dominions of the pope. At sixteen years of age he was admitted into the society of the Jesuits, and the progress he made in every branch of literature and science was surprising. He was first appointed to teach rhetoric, poetry, philosophy, and scholastic divinity, in the Jesuits’ colleges at Parma and Bologna; yet applied himself in the mean time to making observations in geography, chronology, and astronomy. This was his natural bent, and at length he obtained leave from his superiors to quit all other employment, that he might devote himself entirely to those sciences.

He projected a large work, to be divided into three parts, and to contain a complete system of philosophical, mathematical, and astronomical, knowledge. The first of these parts, which regards astronomy, came out at Bologna in 1651, 2 vols. folio, with this title, “J. B. Riccioli Almagestum Novum, Astronomiam veterem novamque | compleotens, observationibus aliorum et propriis, novisque theorematibus, problematibus ac tabulis promotam.” Riccioli imitated Ptolemy in this work, by collecting and digesting into proper order, with observations, every thing ancient and modern, which related to his subject; so that Gassendus very justly called his work, “Promptuarium et thesaurum ingentem Astronomiae.” In the first volume of this work, he treats of the sphere of the world, of the sun and moon, with their eclipses; of the fixed stars, of the planets, of the comets, and new stars., of the several mundane systems, and six sections of general problems serving to astronomy, &c. In the second volume, he treats of trigonometry, or the doctrine of plane and spherical triangles; proposes to give a treatise of astronomical instruments, and the optical part of astronomy (which part was never published); treats of geography, hydrography, with an epitome of chronology. The third comprehends observations of the sun, moon, eclipses, fixed stars, and planets, with precepts and tables of the primary and secondary motions, and other astronomical tables. Riccioli printed also, two other works, in folio, at Bologna, viz. 2. “Astronomia Reformata,” 1665; the design of which was, that of considering the various hypotheses of several astronomers, and the difficulty thence arising of concluding any thing certain, by comparing together all the best observations, and examining what is most certain in them, thence to reform the principles of astronomy. 3. “Chronologia Reformata,” 1665. Riccioli died in 1671, at seventy-three years of age. ¹