There was a time when everyone in the scientific community knew who Guidobaldo del Monte was and no one had heard of Galileo.
4.2 The Marchese del Monte
In the sixteenth century, you could rise socially through the Church or the Army. Money helped of course, but it was less decisive than religious or military connections. Guidobaldo’s father, Ranieri, who came from a wealthy Urbino family, acquired notoriety as an officer and the author of two books on military architecture.2 The Duke of Urbino, Guidobaldo II, impressed by his achievements, conferred upon him the title of Marchese del Monte. When he died in 1587, Guidobaldo inherited his father’s title and the family estate of Mombaroccio.3
A man of many parts, Guidobaldo befriended the poet Torquato Tasso
Guidobaldo published his first book, Mechanics, in 1577, followed in 1579 by a work on the planisphere, and in 1580 by a book on the topical question of the reform of the ecclesiastical calendar.4 In 1588, he was appointed Inspector of the fortifications of Tuscany but he continued to reside at Montebaroccio, and he published that year his second major work in mechanics, a paraphrase of Archimedes’s
Guidobaldo had a younger brother, Francesco Maria, who was born in 1549 and was educated at court in Florence with the future Granduke Francesco and his younger brother, Ferdinando, who entered the Church and was created Cardinal at the age of fourteen by Pope Pius IV
4.3 The Would-be Mathematician and His Master
Writing to a friend in Paris in 1633, Galileo
I shall consider it a favour to receive whatever you have written on the center of gravity. In the light of the essay that you sent me, it can only be excellent. I know that I will learn a lot, having found in your essay depth and rigour, and a way of going about that is as beautiful as it is brief and concise.11
Guidobaldo also informed Galileo
Now I am not unaware that someone may object that for the purpose of these proofs I am assuming as true the proposition that weights suspended from a balance make right angles with the balance—a proposition that is false, since the weights, directed as they are to the center of the universe, are convergent.14
To such objectors, I would answer that I cover myself with the protecting wings of the superhuman Archimedes
, whose name I never mention without a feeling of awe. For he made the same assumption in his Quadrature of the Parabola. And he did so perhaps to show that he was so far ahead of others that he could draw true conclusions even from false assumptions. Yet we must not suppose, in a moment of doubt, that his conclusion is false, since he had earlier demonstrated the same conclusion by another geometric proof. Therefore we must say either that suspended weights actually make right angles with the balance, or that it is of no importance whether they make right angles, but that it is enough that the angles be equal. The latter would perhaps be sounder, unless we wish to say rather that this is a case of geometric license, as when Archimedes assumes that surfaces have weight, and that one surface is heavier than another, whereas, in point of fact, they are entirely without weight.15
Guidobaldo also missed a crucial point that Galileo
It is to Guidobaldo’s credit that in spite of these profound differences in outlook, he continued to value and praise Galileo
4.4 A Patron at Work
After leaving the University of Pisa Galileo
In March 1588 Galileo
Francesco Maria del Monte
I am sorry to hear that you are not treated as you deserve, and even more unhappy that you have little hope of improvement. If you plan to go to Venice this summer, I invite you to come this way. For my part, I will not fail to do what I can to help you. I cannot leave you in this state, and although my means are modest I will use them all in your service.25
In the same letter Guidobaldo laments the fact that several of Galileo’s
Guidobaldo was again true to his word and he got in touch with his cousin, Giovanni Battista del Monte,
Guidobaldo kept a lively interest in Galileo’s
4.5 Guidobaldo’s Influence on Galileo’s Mechanics
As we have seen Galileo called on Guidobaldo perhaps as early as 1588 but no later than 1592. When the two met they discussed mathematics and more specifically the center of gravity of solids, but there is evidence that Guidobaldo also told Galileo about his investigation of projectile motion. Evidence is provided by an experiment that Guidobaldo carried out, perhaps repeatedly, between 1587 and 1592. In a surviving manuscript he states that if a ball is thrown upward with a catapult, a piece of artillery, or by hand, it will trace out the same path in falling as in rising, and the shape will be similar to the one that a rope, loosely attached at both ends, makes with the horizontal line. The shape, he declares, has the form of a parabola or a hyperbola and is better seen with a chain than with a rope. Guidobaldo also adds that projectile motion can be studied to advantage by dipping a ball in ink and throwing it along the surface of an inclined surface so the ball can roll up and down. How far Guidobaldo went in his study of this motion is not known, but we can only be struck by the similarity of his method with Galileo’s
I use an exquisitely round bronze ball, no larger than a nut, which is rolled on a metal mirror that is not held vertically but somewhat tilted, so that the ball rolls over it and presses it lightly. As it travels it leaves a very thin and smoothly traced parabolic line, which is wider or narrower, according as the ball is rolled higher or lower.
The second way consists in driving two nails into a wall at the same horizontal level and at a distance that is twice the width of the rectangle in which we want to draw a semiparabola. From these two nails we hang a fine chain that is long enough for the depth of its sagging to cover the whole expanse.30
Of course, it cannot be excluded that those passages in Guidobaldo’s manu-
scripts were due to Galileo’s influence. Setting aside the issue of authorship, however, it remains true that without Guidobaldo Galileo
Bertoloni Meli, D. (1992). Guidobaldo dal Monte and the Archimedean Revival. Nuncius 7: 3-34
Damerow, P., J. Renn, J. R. (2001). Hunting the White Elephant: When and How Did Galileo Discover the Law of Fall?. In: Galileo in Context Ed. by J. Renn. 21-149
Drabkin, I. E., S. Drake (1960). Galileo Galilei On Motion and On Mechanics. Madison: University of Wisconsin Press.
Drake, S., I. E. Drabkin (1969). Mechanics in Sixteenth-Century Italy. Madison: University of Wisconsin Press.
Galilei, G. (1890–1909). Galileo Galilei, Opere. Firenze: Barbèra.
- (1974). Two New Sciences, Including Centers of Gravity and Force of Percussion. Translated, with Introduction and Notes, by Stillman Drake. Madison: University of Wisconsin Press.
Micheli, G. (1992). Guidobaldo del Monte e la Meccanica. In: La matematizzazione dell'universo Ed. by L. Conti. Assisi: Edizione Porziuncola 87-104
Monte, Guidobaldo del (1577). Mechanicorum liber. Pesaro: Hieronymum Concordiam.
- (1579). Planisphaeriorum universalium theorica. Pesaro: Girolamo Concordia.
- (1580). De ecclesiastici calendarii restitutione opusculum. Pesaro: Girolamo Concordia.
- (1581). Le mechaniche dell'illustriss. sig. Guido Ubaldo de' Marchesi del Monte: Tradotte in volgare dal sig. Filippo Pigafetta. Venezia: Francesco di Franceschi Sanese.
- (1588). In duos Archimedis aequeponderantium libros paraphrasis scholijs illustrata. Pesaro: Hieronymum Concordiam.
- (1600). Perspectivae libri sex. Pesaro: Girolamo Concordia.
- (1609). Problematum astronomicorum libri septem. Venezia: Bernardo Giunti, Giovanni Battista Ciotti e soci.
- (1615). De Cochlea. Venezia: Evangelista Deuchino.
Naylor, R. (1974). The Evolution of an Experiment: Guidobaldo del Monte and Galileo's Discorsi demonstration of Parabolis Trajectory. Physis 16(4): 232-346
Pappus (1588). Pappi Alexandrini mathematicae collectiones a Federico Commandino Urbinate, in latinum conversae, et commentariis illustratae. Pesaro: Girolamo Concordia.
Sinisgalli, R., S. Vastola (1994). La teoria sui Planisferi universali di Guidobaldo del Monte. Firenze: Edizioni Cadmo.
Galileo left the University of Pisa without taking a degree in 1585. This practice was not uncommon, and was not held against him when he applied for a post at the same university four years later.
Galileo also wrote a treatise on military architecture that he sold to young noblemen who attended his private lectures on the topic in Padua, but I have been unable to find whether he used or was at least aware of the works of Guidobaldo’s father.
Guidobaldo signed himself indifferently “dal Monte” or “del Monte.” I shall use the second more common form.
See (Monte 1577, reprinted Venice, Evangelista Deuchino 1615). The work was translated into Italian by Filippo Pigafetta under Guidobaldo’s close supervision (Monte 1581). Selections from this translation are rendered into English in (Drake and Drabkin 1969, 239–328). Del Monte (1579) has recently been made available in Italian with the Latin on facing pages by Rocco Sinisgalli and Salvatore Vastola (Sinisgalli and Vastola 1994). See also (Monte 1580).
Neither Baldi nor Guidobaldo put their names on the title page.
Letter to Elia Diodati, 6th December 1633, in (Galilei 1890–1909, vol. XVII, 524). This would take us back to 1585 but the essay that he distributed to advertise his skill and to apply for a job was not ready before 1587. It is entitled Theoremata circa centrum gravitatis solidorum and was still topical enough in 1638 to be published as an appendix to Galileo’s Two New Sciences. The text is printed in (Galilei 1890–1909, vol. I,187–208), and an English translation is available in (Galilei 1974, 261–280).
Testimonial dated 29 December in 1587 in (Galilei 1890–1909, vol. I, 183). On 12 December 1587, Giovanni Bardi de’ Conti di Vernio, Giovanni Battista Strozzi, Piero Alamanni and Giovanni Battista Ricasoli Baroni had vouched for the originality of Galileo’s demonstrations (ibidem). These were prominent members of the Florentine upper class but not mathematicians.
Letter to Galileo, 16 January 1588, in (Galilei 1890–1909, vol. X, 25). The commendation for conciseness is particularly interesting in view of the fact that Guidobaldo was anything but succinct in his own writings.
Letter to Galileo, 28 May 1588, in (Galilei 1890–1909, vol. X, 74). The objection concerns the demonstration of Galileo’s first proposition, which deals with the distribution of similar weights on different balances (Galilei 1890–1909, vol. I, 187–188). Galilei, Two New Sciences, translated by Drake (Galilei 1974, 261–263). The same objection had been raised by Clavius (letter to Galileo, 16 January 1588, in Galilei 1890–1909, vol. X, 24), to whom Galileo replied on 25 February defending his demonstration (Galilei 1890–1909, vol. X, 27–28). Clavius was not convinced and restated his objection by return of post (letter of 5 March 1588, in Galilei 1890–1909, vol. X, 29–35).
Letter to Galileo, 30 December 1588, in (Galilei 1890–1909, vol. X, 39). In this letter, Guidobaldo signs himself, for the first time, “come fratello” (as a brother). Before this date, he signed himself, more formally, as “Ser.
re,” an abridged form of “Servitore” (Your servant).
Letter to Galileo, 3 September 1593, in (Galilei 1890–1909, vol. X, 62). The reference is to Adrianus Romanus, Ideae mathematicae pars prima sive methodus polygonorum, Louvain, Johannes Masius 1593. The work is dedicated to Clavius.
Letter to Galileo, 16 June 1610, in (Galilei 1890–1909, vol. X, 372). The comparison of Galileo with Columbus is also found in Kepler’s letter to Galileo of 19 April 1610 (Galilei 1890–1909, vol. X, 324 and 325), and the one that he was sent by Campanella on 13 January 1611 (Galilei 1890–1909, vol. XI, 24).
See (Galilei 1890–1909, vol. VIII, 186–187); English translation in Galilei, Two New Sciences, by Drake (Galilei 1974, 142–143). See (Galilei 1890–1909, vol. VIII, 313); English translation in Galileo, Two New Sciences by Drake (Galilei 1974, 142–143). See the discussion in (Naylor 1974; Damerow et.al. 2001).