Risposta alle opposizioni del S. Lodovico delle Colombe, e des S. Vincenzio di Grazia, contro al trattato del Sig. Galileo Galilei, delle cose che stanno su l’acqua o che in quella si muovono ... Nella quale si contengono molte considerazioni filosofiche remote dalle vulgate opinioni.

Florence: Cosimo Giunti, 1615.

First edition, rare, from the Riccati library, of Galileo’s principal text on the controversy over floating bodies. This work was written as a reply to two attacks by Delle Colombe (1565-1623) and Di Grazia on Galileo’s 1612 treatise on floating bodies, Discorso … intorno alle cose che stanno ub su l’acqua, o in quella si muovono. Although Galileo drafted replies to these (as well as two other polemical attacks on his treatise), this was the only one to be published. Like several of his polemics of this period, it appeared under the name of a colleague, in this case his pupil and friend Castelli (1578-1643). “Shortly after his return to Florence, Galileo became involved in a controversy over floating bodies. In that controversy an important role was played by Colombe, who became the leader of a group of dissident professors and intriguing courtiers that resented Galileo’s position at court. Maffeo Barberini—then a cardinal but later to become pope—took Galileo’s side in the dispute. Turning again to physics, Galileo composed and published a book on the behavior of bodies placed in water, in support of Archimedes and against Aristotle, of which two editions appeared in 1612. Using the concept of moment and the principle of virtual velocities, Galileo extended the scope of the Archimedean work beyond purely hydrostatic considerations … The book on bodies in water drew attacks from four Aristotelian professors at Florence and Pisa, while a book strongly supporting Galileo’s position appeared at Rome. Galileo prepared answers to his critics, which he turned over to Castelli for publication in order to avoid personal involvement. Detailed replies to two of them (Colombe and Grazia), written principally by Galileo himself, appeared anonymously in 1615, with a prefatory note by Castelli implying that he was the author and that Galileo would have been more severe” (DSB). In the present reply to his academic critics, Galileo both enlarged the scientific reasoning behind his position and presented a vigorous philosophical defence of that position. In the second reply to Grazia, Galileo states that he made use of two basic principles, “that equal weights moved with equal speed are of like power in their effects, and that greater heaviness of one body could be offset by greater speed of another” (Stillman Drake). This copy contains the rare two additional leaves (Y2) completing the errata and giving the registration and printer’s device, not recorded by Cinti.

Provenance: From the library of the Riccati family (bookplate on front paste-down), whose most prominent bibliophile members were Jacopo Francesco Riccati (1676-1754) and his son Vincenzo (1707-75), both mathematicians and physicists.

About the first week in August [1611] a memorable dispute arose between Galileo and some philosophers over the conditions governing the floating and sinking of bodies in water … Galileo, his friend Filippo Salviati, and two professors of the University of Pisa were discussing condensation when one of the professors, Vincenzio di Grazia, brought up the example of ice, which he considered to be simply condensed water. Galileo replied that ice should rather be regarded as rarefied water, since ice floats and must therefore be less dense than water. The professors contended that ice floated because of its broad flat shape, which made it impossible for the ice to cleave-downward through the water. Galileo pointed out that ice held forcibly under water and then released seemed to manage to cleave through it upward, even though then its own weight ought to help hold it down. When it was argued that a sword struck flat on water resists, while edgewise it cuts easily through water, Galileo explained the irrelevance of this observation. He granted that the speed of motion through water was indeed affected by shape, as Aristotle himself had said, but not the simple fact of rising or sinking through water, which was the point at issue. Water offered resistance not to division, but to speed of division, while spontaneous rising or sinking of solids in water was governed only by the Archimedean principle. This discussion did not convince the professors.

“Three days later, Di Grazia told Galileo that he had met someone who said he could show Galileo by experiments that shape did play a role in floating and sinking in water; this was Colombe, who had not been present at the initial conversation. Galileo wrote out the conditions of the contest: Colombe was to show by experiment that a sphere of some material that sank in water would not sink if the same material were given some other shape. Canon Francesco Nori was to referee the experiments presented by both sides. Colombe added the stipulation that he would decide on the material and shapes to be used, the material to be of nearly the same density as water itself, and Filippo Arrighetti was made co-judge with Nori.

“During the next few days Colombe exhibited to many people his experiments, made with lamina, spheres, and cylinders of ebony. Galileo perceived that the contest was going to become a verbal one in this way; the real issue concerned the rising or sinking of bodies placed in water, not the behavior of bodies placed on its surface and incompletely wetted. Presumably he had the support of the referees on this, because when the meeting at Nori’s house was scheduled, Colombe failed to appear. Galileo then sent to Colombe a newly worded challenge, specifying that all the materials used were to be placed entirely in the water before each experiment with them. A date was set for the meeting, this time at Salviati’s house in Florence (not at his villa, several miles distant from the city).

“By this time gossip about the contest came to the attention of Cosimo de’ Medici, who told Galileo not to engage in public disputes but rather to write out his arguments in a dignified form worthy of a court representative. When the scheduled meeting took place Galileo accordingly refused to enter into oral dispute with Colombe, saying that he would instead write out his position along with his arguments for it. This he did during September in a manuscript which includes his account of the entire affair up to this point … Galileo’s Discourse on Bodies on or in Water, begun during hisillness at Florence late in 1611, was completed at Salviati’s villa in the spring of 1612 …

“The first book to be published in reply to Galileo was called Considerations of the Unknown Academician and appeared in August 1612. Its author is usually said to have been Arturo d’Elci, treasurer of the University of Pisa, whose name indeed appears in the dedicatory material but who there declared himself not the author but the translator of the contents (from Latin into Italian). In my opinion it was composed by Flaminio Papazzoni … The Considerations gave a reasonable and nonpartisan exposition of the Aristotelian position, unlike the three other books subsequently published against Bodies in Water …

“During August [1612] Galileo sent to the printer some additions to be made in a second edition of Bodies in Water, the original edition having been quickly sold out and the book being still in demand … Also included was some material written in reply to the Considerations of the Unknown Academician which had just appeared …

“A second attack against Bodies in Water now appeared, written by Giorgio Coresio, a Greek professor at Pisa. Castelli began to list its errors, having already received Galileo’s notes on the Considerations of the Unknown Academician. Galileo had decided that any reply to his adversaries on floating bodies should appear as a defense by a friend; the only exception was an intelligent critique sent in September by Tolomeo Nozzolini to Archbishop Marzimedici and forwarded by him to Galileo. Also in December [1612] a third book against Bodies in Water was printed at Florence, by Colombe [Discorso apologetico ... d'intorno al discorso di Galileo Galilei circa le cose, che stanno sù l'acqua, ò che in quella si muovono]. As with the other two, Galileo wrote extensive notes in reply to this and turned them over to Castelli for editing. He appears also to have solicited comments from others” (Drake, Galileo at Work, pp. 169-197).

“Before [Castelli’s] response came out, both authors who might have hidden behind the ‘Anonymous Academician’ (Pannocchieschi d'Elci and Papazzoni) died, and Coresio (a native Greek and a follower of the Greek Orthodox Church) had run into trouble with the Florentine Inquisition. Consequently, Castelli responded only to delle Colombe and di Grazia. His fat tome (widely emended by Galileo) came out in 1615, when Castelli was already a professor of mathematics at Pisa” (Biagioli, Galileo, Courtier, p. 231).

“Galileo did not condescend to reply to his opponents under his own name. Instead he provided the ammunition for a counter attack by Castelli published in 1615. By then the battlefield had many fortified places. Castelli required 18 salvos to answer 25 objections to Galileo’s hints on atoms fired off by a single opponent, Giorgio Coresio. Although insignificant in their detail, these maneuvers taken together had the important consequence of increasing and hardening the opposition to Galileo in Florence and Pisa already flourishing under the gentle heat of jealousy. His highly paid sinecure, charged on funds reserved to the University of Pisa from tax collected from ecclesiastical holdings, excited envy and resentment among courtiers, clerics, and professors. And his supercilious refusal to name his opponents in his replies (to do them a favor, he said), his sending his squire to rebut them, and his cocksure insistence that physics must bow down to mathematics irritated even people inclined to support him. Campanella may speak for all of them. Writing from his dungeon in Naples, he upbraided Galileo for freighting floating bodies with propositions neither known to be true nor easily defended, ‘so that you give your enemies an opening for denying all the celestial things you pointed out . . . O Dio what a pity it was to humble the immense pride with which you could have gone forth so happily revealing to mortals so many great things!’” (Heilbronn, Galileo, p. 183).

Castelli’s experience in acting in Galileo’s defense in the buoyancy dispute led to his later work on hydrodynamics, for which he is now best known. “In 1628 he published the important work on hydraulics, Della Misura dell'Acque Correnti, or ‘On the Measurement of Running Waters,’ a book that may be considered the foundation of modern hydrodynamics” (Galileo Project).

Carli and Favaro 66; Cinti 51; Riccardi I, 289. Biblioteca mechanica p. 126.



4to (217 x 155mm), pp. [iv], 1-334, 319, [3], [2], woodcut printer's device on title, large device on verso of final leaf, historiated initials (light dampstain to upper outer corner). Eighteenth-century marbled half-calf and marbled boards, flat spine gilt, red and black spine labels, marbled endpapers (minor worming).

Item #5769

Price: $25,000.00