Ratio ponderum librae et simbellae: In qua quid e Lothario Sarsii libra astronomica, quidque e Galilei Galilei simbellatore, de cometis statuendum sit, collatis utriusque rationum momentis, philosophorum arbitrio proponitur.

Naples: Matthaeus Nuccius, 1627.

First Italian edition, very rare, of Grassi’s counter-polemic against Galileo’s Il saggiatore (1623). This is the concluding work in the series of publications which document the “controversy of the comets,” one of the most infamous polemics in the history of science. According to Drake, these texts “deserve study for their bearing upon the origin of modern scientific method … The controversy is of both scientific and philosophical significance because it was in this connection that Galileo disclosed his conception of scientific method.” The Ratio ponderum was first published at Paris the year before, but that edition was very unsatisfactory (see below) − the present Naples edition “took care of the numerous errors and omissions in the mangled Paris edition” (Feingold, p. 152). It was dedicated to Cardinal Francesco Boncompagni, the Archbishop of Naples (which explains why it was published there). Galileo preferred not to reply to the Ratio ponderum, and thus the controversy came to an end. “The dispute over comets had consequences of great significance both to Galileo and to science in general, as the favorable reception of [Il saggiatore] led him to proceed with the publication of the much more famous Dialogue, for which he was later imprisoned by the Inquisition. That fateful event was in turn intimately connected with the rift between Galileo and the Jesuits, which was widened and made permanent, if indeed it did not originate, in the public dispute about comets. Thus the controversy is closely linked with some of the most dramatic events associated with the dawn of our modern era” (Drake, The Controversy on the Comets of 1618, p. vii). The Ratio ponderum may have been written in collaboration with Christoph Scheiner, who had been involved in a separate controversy with Galileo in 1613 over priority for the discovery of sunspots. OCLC lists copies in US at Brown, Burndy, Caltech, Columbia, Oklahoma & U. Penn. ABPC/RBH list only two copies.


In the latter part of 1618, three comets appeared in the sky over Italy, eliciting lively debate among astronomers as to their nature since, according to Aristotelian orthodoxy, objects beyond the moon could not change shape or state. Unable to observe the comets due to ill health, Galileo nevertheless discussed the phenomena with numerous visitors but made no move to express his opinions about the comets to the wider public. This changed when, in the following year, Orazio Grassi gave a lecture at the Collegio Romano, published anonymously under the title De tribus cometiis anni 1618, and giving an interpretation of the events using Tycho Brahe’s geocentric theories, which were acceptable to the Jesuits. Galileo construed this as an attack on his Copernicanism and published Discorso delle comete, a refutation of Grassi (although Grassi is not mentioned directly), under the name of his disciple Mario Guiducci (1585-1646). This in turn provoked a reply by Grassi, under the pseudonym Lotario Sarsi, who pretended to be a pupil of Grassi, entitled Libra astronomica ac philosophica, towards the end of 1619. Guiducci responded to the Libra astronomica with his Letter to Father Tarquino Galluzzi (1620), his teacher at the Collegio Romano, but this time Galileo himself decided to respond, the challenge to his authority and prestige was now too much. He began to write Il Saggiatore, although this would not appear for another four years.


“Grassi may well have been the first person in Rome to purchase a copy of [Il Saggiatore], for it appears that Galileos friends managed to play a little trick on hm. The Master of the Sacred Palace, Niccolo Ridolfi, provided the owner of the Sun Bookshop with one of the copies submitted for the imprimatur, and word was sent to Grassi, who rushed to the shop, and, upon reading the frontispiece, “changed color.”As Rinuccini reported to Galileo on 3 November 1623, he had heard from the bookseller that Grassi declared that though Galileo “had made him wait anxiously three years for this response,” he would relieve Galileo’s anxiety in just three months … [But] Grassi was evidently in two minds about responding. On 2 December 1623 Galileo was informed that in a conversation with Thomaso Rinuccini’s friend, the Jesuit had commended Il Saggiatore, admitting that though there was much good in it, in view of the situation, he wanted to reply. Nevertheless, Grassi added, he could not turn to it before the end of the summer vacation, and more pointedly unlike Galileo, he lacked friends who could defray the cost of printing. He further insisted that his response would avoid sardonic remarks of the sort Galileo had generously interspersed in his book. Even as Grassi contemplated a response, he expressed a simultaneous desire to reconcile with Galileo during the latter’s approaching visit to Rome. A few days later, however, Grassi’s mood had changed. Rinuccini’s friend found him agitated by reports from Florence that Il Saggiatore “must have shut the mouths of all the Jesuits, who will not know how to reply.” According to Rinuccini, Grassi retorted: “if the Jesuits know how to respond to a hundred heretics a year, they should be able to do the same with one Catholic”” (Feingold, p. 146).


In the end, it was not until 1626 that Grassi, who meanwhile had begun to frequent Guiducci and to relax his polemical attitude, published his Ratio ponderum, in which he again attacked Galileo. “The answer to The Assayer was published at Paris in I626 with the curious title, Ratio Ponderum Librae et Simbellae, and once more the pseudonym of Sarsi was used, its author still pretending to be a pupil of Grassi. The title appears to mean ‘A Reckoning of Weights for the Balance and the Small Scale’; the unusual word simbella (a scale used to weigh single coins) may be meant to carry a pun on cimbella (a challenge). The heavy wit with which Grassi thus attempted to deride Galileo’s delicate assayer’s balance is typical of that which pervades the entire book; thus the author pretends that saggiatore really meant ‘winetaster’ (assagiatore), and that the appearance of Galileo’s book in the autumn months suggested that its author had been imbibing too freely of new wine” (Drake, Controversy, p. xx).


“Though published under the same pseudonym as the Libra of 1619, this new book may have been written by Grassi in collaboration with Scheiner (1573-1650) ... [At the end of 1626] Galileo was told that Grassi had printed his reply to the Assayer, copies having reached Rome from Paris where it appears to have been sent for publication after some difficulties about having that done in Italy ... [In 1628] he considered replying to the second “Sarsi” book, which he annotated sarcastically, but in the end he agreed with Cesi and others at Rome that it was unworthy of the dignity of an answer” (Drake, Galileo at Work, pp. 304-9 and footnote 3).

The fact that the Ratio ponderum was written under a pseudonym may explain why it was first published at Paris. In 1621, the Superior General of the Society of Jesus, Mutio Vitelleschi (1563-1645), prohibited its members from publishing anonymously or pseudonymously, as such disguises were easily found out and reflected badly both on the author and the Society. The distance, and resulting difficulty of communication, between author and printer seems to have resulted in the numerous errors and omissions in the first edition (see below).


Grassi (1583-1654) was born in Savona, then part of the Republic of Genoa. He entered the novitiate of the Society of Jesus in Rome in 1600, where he studied until 1610. He pronounced solemn vows in the Society in 1618, at which time he received Holy Orders as a priest, following which he was given the chair in mathematics. Grassi requested to be released from his teaching duties at the Collegio Romano in late June 1624, a result, according to Feingold, of internal pressure on Grassi to conform. “Further to substantiate the conclusion that Grassi’s resignation was not altogether voluntary was his new assignment as confessor to the Congregation – a task that, when given to mathematicians, often served as a means to make a Jesuit novator contemplate his vocation and the aims of secular learning within the Order. However, removal from teaching and the assignment of pastoral duties evidently were insufficient measures to steer Grassi away from the new science, as is evident in the friendship he struck up with Guiducci, and his superiors resolved that he should prove his orthodoxy by publishing a response to Il Saggiatore.


“Guiducci must have heard some garbled accounts of what had transpired, which made him conclude, erroneously, that the authorities objected to the publication of Grassi’s response. Thus, on 4 January 1625 he wrote Galileo that Grassi had encountered some difficulties with his confreres over the publication of his response, adding a week later that the project appeared frozen because of obstacles raised by General Vitelleschi. Over the next few weeks Guiducci was unable to find out more concrete details, and his correspondence came to an end in late February. By April 1625 Grassi was appointed Rector of the College of Sienna, and this allowed for another delay. By early 1626, however, the manuscript of the Ratio was ready for the press. From the fact that it was sent to Paris to be printed, and from the correspondence between the author and General Vitelleschi, we may safely deduce that it was actually Grassi’s superiors who actually took charge of publication. All that Grassi could do was to complain bitterly of the carelessness of the Parisian Jesuits who handled the manuscript. Vitelleschi, however, put the blame on the printers: “I would have hoped that your Reverence had had complete satisfaction as to the printing of your apologia, which is also being looked after by Father Arnulfo … and I am extremely unhappy that it has come out badly, as your Reverence reports. I believe that it is not due to the lack of diligence on the part of the Fathers, but to the Printers to whom the author’s presence usually creates a sense of application, etc. With all that we will not omit sending our advice. But I am afraid that it will be in vain, since I fear that the advice will arrive when the printing is finished and it will be necessary to seek patiently a remedy elsewhere.” Cognizance of the circumstances of publication may help to lay to rest yet another conspiratory theory suggested by Redondi, this time regarding the “miraculous” materialization of an imprimatur for the Ratio – dated 4 May 1627 and missing in the Paris edition – in the Naples printing of the book. Simply put, Grassi availed himself of the “remedy” suggested by Vitelleschi and produced an Italian impression that took care of the numerous errors and omissions in the mangled Paris edition.


“In suggesting that the Ratio was at least partly extracted from Grassi, I am not suggesting that the Jesuit had not entertained thoughts about publishing a response. But he was of two minds, intermittently hoping that a reconciliation with Galileo might make a rejoinder unnecessary. Unfortunately, Galileo refused to oblige, confident that Il Saggiatore was beyond Grassi’s reach … Galileo’s justification for his refusal [was] that Grassi “deserved to pay the penalty for having been the first to provoke, by furiously opposing the truth”.


“Grassi still managed to retain a dignified demeanour in the Ratio, no matter that once he broached the theological implications of Il Saggiatore … For his part, while soiling his copy of the book with the most abusive expletives he ever committed to paper, Galileo deemed another response unnecessary. His victory was complete and it was he who, in a manner of speaking, annihilated the Jesuits. Grassi never published a scientific work again” (Feingold, pp. 151-2).


Carli-Favaro, p. 24; Cinti 80; Lalande pp. 189-90; Riccardi I, 628; Sommervogel III, 1685-6. Feingold, ‘The grounds for conflict: Grienberger, Grassi, Galileo, and posterity,’ in The New Science and Jesuit Science, 2003.

4to (210 x 152 mm), contemporary limp vellum with manuscript lettering to spine, pp. [vii], 149, [3], with engraved device on title and one engraved plate. Very light toning to a few gatherings, final leaves with soe spotting.

Item #4009

Price: $5,000.00