Abstract

An outdated geography supplies the bond among the thirty‐one articles in Sur les traces des Cassini. In the seventeenth century, when the Italians Gian Domenico Cassini and his nephew Giacomo Filippo Maraldi were born in Perinaldo, north of Genoa, their birthplace belonged to the County of Nice. Hence the rationale of building a set of papers on astronomy in the south of France around Cassini I and his family, which for four generations ran the Royal Observatory in Paris.Over half the articles concern the Cassinis, mostly Cassini I and his great‐great‐grandson and namesake Cassini IV. There was also a Cassini V, Henri de Cassini, who countered the family genius and stamina by preferring botany and dying early, of the same outbreak of cholera that took the life of Sadi Carnot, without having created Cassini VI. He had already entered the Academy of Sciences with a push from his father. “I dare to beg of you [Cassini IV wrote to his fellow academician A. M. Ampère] to consider whether this unique situation in the history of letters, [a family's] devotion to the sciences for five successive generations and 170 years, ought not add some weight to the scientific credentials of my son.” It is hard to refuse the children of important alumni.The portion of Traces dealing more directly with astronomy in the south of France gets off to a distant start. Pytheas of Marseilles, who lived about 350 b.c., sailed to the Orkneys and the Baltic and earned himself the reputation of a liar back home for his stories of midnight suns and frozen lakes. He measured the latitude of Marseilles, the obliquity of the ecliptic, and the size of the earth. Ptolemy praised him. Strabo did not: “Pytheas lied about everything and covered it up with his knowledge of astronomy and numbers.”No traces worth following up were laid down for just under two thousand years. Then, in 1580, Nicolas Fabri de Peiresc first saw the light of day. He lived in Italy for four years as a very young man, deepening his knowledge of astronomy and human nature and meeting the main future actors in the Galileo affair: Galileo himself, Bellarmine, and Matteo Barberini . At his center in Aix‐la‐Provence, Peiresc made many useful astronomical observations, some in collaboration with Pierre Gassendi. He died in harness, worrying about the change of the obliquity since the days of Pytheas.There follow articles on Provençal astronomers who determined longitude and latitude at sea, on neglected observers in Languedoc who assisted the cause of the Enlightenment, and on modern observatories in the south of France. The political circumstances after the defeat of 1870–1871 favored decentralization of astronomy away from the Paris Observatory. In Italy, too, recent political events—the unification of 1870—made a restructuring of astronomical institutions desirable and possible. But whereas France had too few observatories, Italy had too many. Georges Rayet and Pietro Tacchini, both astrophysicists, compared the circumstances in their countries and made mutually reinforcing proposals to their colleagues and governments. Their respective proposals, most of which were enacted, called for reassigning some Italian observatories to meteorological work, building new observatories in Besançon, Bordeaux, and Lyon, and refurbishing older ones at Marseilles and Toulouse. Once again, as in the days of Cassini I, Italy made a decisive contribution to the practice of astronomy in France.Sur les traces des Cassini mixes slight and weighty work, admits antiquarian and broader approaches, offers new documentation, displays pertinent illustrations, and does it all at a high level of scholarship. Since, because of its title, the book's primary audience probably will be people interested in the Cassinis, its fullest articles about them may usefully be mentioned here: Anna Cassini on Cassini's brief return to Italy, 1694–1696; Claude Teillet on the provincial life and poetry of Cassini IV; Christiane Demeulenaere‐Douyère on the Cassinis and the Académie des Sciences; Fabrizio Bonoli and Alessandro Braccesi on Cassini I's astronomical work in Bologna, with full bibliography; and Monique Pelletier on the Cassini map of France, on which she has written a book . Pytheas and Peiresc are the subjects of collaborative articles by Simone Arzano and Yvon Georgelin