Galileo's Daughter

by Dava Sobel

  Galileo also secured a bonus in personal liberty by arranging for his university appointment at Pisa to entail no noisome teaching duties. He would be free to study the world around him for the rest of his days, and to publish his discoveries for the benefit of the public under the protection of the grand duke, who promised to pay for the construction of new telescopes.

  [IV]

  To have the truth

  seen and recognized

  Nine-year-old Livia rode south with her father when he moved to Florence to assume his new court post in September of 1610. They left behind the serpentine canals of Venice, where the doge’s palace brushed the water’s edge like a fantasy spun from pink sugar and meringue. They crossed the fertile Po Valley and the Apennine spine of the Italian peninsula into the foreign country where the grand duke reigned. Italy in the seventeenth century comprised a pastiche of separate kingdoms, duchies, republics, and papal states, united only by their common language, often at war with one another, and cut off from the rest of Europe by the Alps.

  The landscape changed. Spires of cedar and cypress trees soared out of the rolling terrain, while ocher stucco houses sank roots into it. Here Galileo introduced Livia to the earth tones and square, sensible beauty of Tuscany. His older daughter, Virginia, already awaited them in Florence. She had gone the previous autumn at the insistence of Galileo’s mother, who took Virginia home with her after an unhappy visit to Padua. Finding her son too absorbed in his new spyglass to extend the sort of hospitality she demanded, and her not-quite daughter-in-law not worthy of her attention, Madonna Giulia cut short her intended stay and returned to Tuscany.

  “The little girl is so happy here,” she crowed in a letter to Alessandro Piersanto, a servant in Galileo’s house, “that she will not hear that other place mentioned any more.”

  Neither Virginia nor Livia had any idea when they would ever see their brother, Vincenzio, again. For the time being at least, Galileo deemed it best for the boy, still a toddler, to remain in Padua with Marina.

  Soon after Galileo’s departure, Marina married Giovanni Bartoluzzi, a respectable citizen closer to her own social station. Galileo not only approved of their union but also helped Bartoluzzi find employment with a wealthy Paduan friend of his. Still, Galileo continued sending money to Marina for Vincenzio’s support, and Bartoluzzi, in turn, kept Galileo supplied with lens blanks for his telescopes, procured from the renowned glassworks on the Island of Murano, within the waterways of Venice, until Florence proved a source of even better clear glass.

  Galileo rented a house in Florence “with a high terraced roof from which the whole sky is visible,” where he could make his astronomical observations and install his lens-grinding lathes. While waiting for the place to become available, he stayed several months with his mother and the two little girls in rooms he let from his sister Virginia and her husband, Benedetto Landucci. Galileo’s relatives provided an amicable enough atmosphere in their home, despite the recent legal fracas, but “the malignant winter air of the city” made him miserable.

  “After the absence of so many years,” Galileo lamented, “I have experienced the very thin air of Florence as a cruel enemy of my head and the rest of my body. Colds, discharges of blood, and constipation have during the last three months reduced me to such a state of weakness, depression, and despondency that I have been practically confined to the house, or rather to my bed, but without the blessing of sleep or rest.”

  He devoted what time his health allowed to the problem of Saturn, much farther away than Jupiter—at the apparent limit of his best telescope’s resolution—where he thought he could just discern two large, immobile moons. He described what he had seen in a Latin anagram, which, when correctly unscrambled, said, “I observed the highest planet to be triple-bodied.” Thus staking his claim to the new discovery without making a fool of himself before establishing proper confirmation, he dispatched the anagram to several well-known astronomers. None of them correctly decoded it, however. The great Kepler in Prague, who by this point had held the telescope and deemed it “more precious than any scepter,” misinterpreted the message to mean Galileo had discovered two moons at Mars.*

  All through that same autumn of 1610, with Venus visible in the evening sky, Galileo studied the planet’s changing size and shape. He kept a telescope trained on Jupiter, too, in a protracted struggle to ascertain the precise orbital periods of the four new satellites to further validate their reality. Meanwhile, other astronomers complained of struggling just to catch sight of the Jovian satellites through inferior instruments, and therefore they questioned the bodies’ very existence. Despite Kepler’s endorsement, some sniped that the moons must be optical illusions, suspiciously introduced into the sky by Galileo’s lenses.

  Now that the moons had become matters of the Florentine state, this situation required immediate remedy to protect the honor of the grand duke. Galileo scrambled to build as many telescopes as he could for export to France, Spain, England, Poland, Austria, as well as for princes all around Italy. “In order to maintain and increase the renown of these discoveries,” he reasoned, “it appears to me necessary . . . to have the truth seen and recognized, by means of the effect itself, by as many people as possible.”

  Famous philosophers, including some of Galileo’s former colleagues at Pisa, refused to look through any telescope at the purported new contents of Aristotle’s immutable cosmos. Galileo deflected their slurs with humor: Learning of the death of one such opponent in December 1610, he wished aloud that the professor, having ignored the Medicean stars during his time on Earth, might now encounter them en route to Heaven.

  To cement the primacy of his claims, Galileo thought it politic to visit Rome and publicize his discoveries around the Eternal City. He had traveled there once before, in 1587, to discuss geometry with the preeminent Jesuit mathematician Christoph Clavius, who had written influential commentaries on astronomy, and who now would surely welcome news of Galileo’s recent work. Grand Duke Cosimo condoned the trip. He thought it might heighten his own stature in Rome, where his brother Carlo currently filled the traditional position of resident Medici cardinal.

  Unfortunately, Galileo’s sickly reaction to the air of Florence prevented him from setting out until March 23, 1611. He spent six days on the road in the grand duke’s litter, and at night he set up his telescope in every stop along the way—San Casciano, Siena, San Quirico, Acquapendente, Viterbo, Alonterosi—to continue tracking the revolutions of Jupiter’s moons.

  Upon Galileo’s arrival at week’s end, the warmth of his Roman welcome surprised him. “I have been received and feted by many illustrious cardinals, prelates, and princes of this city,” he reported, “who wanted to see the things I have observed and were much pleased, as I was too on my part in viewing the marvels of their statuary, paintings, frescoed rooms, palaces, gardens, etc.”

  Galileo garnered the powerful endorsement of the Collegio Romano, the central institution of the Jesuit educational network, where Father Clavius, now well into his seventies, was chief mathematician. Clavius and his revered colleagues, regarded by the Church as the top astronomical authorities, had obtained telescopes of their own, and now as a group corroborated all of Galileo’s observations. Bound as these Jesuits were to Aristotelian belief in an unchanging cosmos, they did not deny the evidence of their senses. They even honored Galileo with a rare invitation to visit.

  Page from Galileo’s notebook tracking the orbits of the satellites of Jupiter

  The Collegio Romano

  “On Friday evening of the past week in the Collegio Romano,” a social bulletin reported in early April, “in the presence of cardinals and of the Marquis of Monticelli, its promoter, a Latin oration was recited, with other compositions in praise of Signor Galileo Galilei, mathematician to the grand duke, magnifying and exalting to the heavens his new observation of new planets that were unknown to the ancient philosophers.”

  This marquis of Monticelli who attended Galileo’
s fete was an affable, idealistic young Roman named Federico Cesi. His handful of noble titles also pronounced him duke of Acquasparta and prince of San Polo and Sant’Angelo. In addition to these honors he bore by birth, he had distinguished himself in 1603, at age eighteen, by founding the world’s first scientific society, the Lyncean Academy. Cesi pooled his wealth, foresight, and curiosity to establish a forum free from university control or prejudice. He made the academy international from the outset—one of its four charter members being Dutch—and multidisciplinary by design: “The Lyncean Academy desires as its members philosophers who are eager for real knowledge and will give themselves to the study of nature, especially mathematics; at the same time it will not neglect the ornaments of elegant literature and philology, which, like graceful garments, adorn the whole body of science.” The choice of the sharp-eyed lynx as totem emphasized the importance Cesi placed on faithful observation of Nature. At official ceremonies, Cesi sometimes wore a lynx pendant on a gold neck chain.

  Cesi entreated Galileo, who embodied the Lynceans’ organizing principles, to join the academy during his stay in Rome. He held a banquet in Galileo’s honor on April 14, on the city’s highest hill, where one of the other dinner guests, Greek mathematician Giovanni Demisiani, proposed the name “telescope” for the spyglass Galileo had brought along to show the party the moons of Jupiter. The men lingered long into the night enjoying the novel views. To dispel any possible doubt about his instrument’s veracity, Galileo also aimed the telescope point-blank at the exterior wall of the Lateran Church, where a chiseled inscription attributed to Pope Sixtus V could be easily read by all, though it stood over a mile away.

  Galileo’s formal election to the Lyncean Academy the next week privileged him to add the title “Lyncean” after his signature on any literary work or private correspondence, which practice he took up immediately. Furthermore the academy, Cesi promised, would become Galileo’s publisher.

  Lyncean Academy coat of arms

  Before leaving Rome triumphant at the end of May, Galileo gained a favorable audience with the reigning pope, Paul V, who ordinarily took no great interest in science or scientists. Galileo also made the acquaintance of Maffeo Cardinal Barberini, the man destined to become the future Pope Urban VIII. Cardinal Barberini, a fellow Tuscan roughly the same age as Galileo and, like him, an alumnus of the University of Pisa, admired the court philosopher’s scientific work and shared his interest in poetry.

  Chance threw Galileo and Barberini together again the following fall, in Florence, when the visiting cardinal was the grand duke’s dinner guest, and Galileo the after-dinner entertainment. On that night, October 2, 1611, Galileo staged a debate with a philosophy professor from Pisa, arguing on the subject of floating bodies for the edification of all present. Galileo’s explanation of what made ice and other objects float in water differed sharply from the Aristotelian logic being taught in the universities, and his adroit verbal decimation of any opponent made for spectator sport at the Tuscan court.

  “Before answering the adversaries’ arguments,” a contemporary observer reported of Galileo’s debating style, “he amplified and reinforced them with apparently very powerful evidence which then made his adversaries look more ridiculous when he eventually destroyed their positions.”

  The prevailing wisdom about bodies in water held that ice was heavier than water, but that broad, flat-bottomed pieces of ice floated anyway because of their shape, which failed to pierce the fluid surface. Galileo knew ice to be less dense than water, and therefore lighter, so that it always floated, regardless of its shape. He could show this by submerging a piece of ice and then releasing it underwater to let it pop back up to the surface. Now, if shape were all that kept ice from sinking, then shape should also prohibit its upward motion through water—and all the more so if ice truly outweighed water.

  Invited to join the discussion on floating bodies, Cardinal Barberini enthusiastically took Galileo’s side. Later, he told Galileo in a letter: “I pray the Lord God to preserve you, because men of great value like you deserve to live a long time to the benefit of the public.”

  Cardinal Barberini had come to Florence to visit two of his nieces—both nuns, who lived at a local convent. This coincidence may have suggested a course to Galileo concerning his own two daughters, though the thought of placing them in a convent could have occurred to him naturally enough. Not only had his two sisters been schooled and sheltered in convents, but such institutions proliferated all around him. In Galileo’s time, in addition to nearly thirty thousand males of all ages and more than thirty-six thousand females living in the city of Florence, a separately tallied population of “religious"—one thousand men and four thousand women—dwelled in twenty-seven local monasteries and fifty-three convents. The pealing of bells from atop these cloistered residences reverberated through the air, day and night, as constant a note in the din of life as birdsong or conversation. Fully 50 percent of the daughters of Florentine patrician families spent at least part of their lives within convent walls.

  Galileo’s sisters had eventually left the convent for holy matrimony, but he foresaw no such future for his daughters because of the conditions of their birth. At their present ages, ten and eleven, they were too young to take religious vows, yet they might well enter a convent before the canonical age of sixteen in any case, and bide the intervening years in a safer environment than he could provide for them, considering the plights of the women in his family: Madonna Giulia, always argumentative, had grown more difficult as she grew older, while his sisters were both burdened with their own young children and frequent pregnancies.

  Galileo’s poor health perhaps rushed his judgment on the matter, since he again took seriously ill within days of the court dispute over floating bodies and did not recover for several months. His illness forced him to flee the city for his private sanitarium at the Villa delle Selve, the country home of a generous good friend. From his bed in the hills, at the grand duke’s behest, Galileo began putting his thoughts on floating bodies into a book-length treatment, to be called Discourse on Bodies That Stay Atop Water or Move Within It.

  While at work on this project, he received a disturbing letter from an artist acquaintance of his in Rome: “I have been told by a friend of mine, a priest who is very fond of you,” the painter Ludovico Cardi da Cigoli warned Galileo, “that a certain crowd of ill-disposed men envious of your virtue and merits met at the house of the archbishop there [in Florence] and put their heads together in a mad quest for any means by which they could damage you, either with regard to the motion of the earth or otherwise. One of them wished to have a preacher state from the pulpit that you were asserting outlandish things. The priest, having perceived the animosity against you, replied as a good Christian and a religious man ought to do. Now I write this to you so that your eyes will be open to such envy and malice on the part of that sort of evildoers.”

  These gathering storms may have confirmed Galileo’s decision to cloister his daughters in the protective environment of a convent, for during the same period he wrote the letters that set the placement process in motion.

  He insisted the girls stay together, despite the frowning of the Florentine Sacred Congregation of Bishops and Regulars on the question of admitting two siblings into the same convent. Although Galileo did not set down his reasons for his wish, he may well have seen Livia already displaying the morbid tendency to melancholy and withdrawal that would shade her adult personality. Without her sunny older sister to counteract those dark moods, what would become of her? No other Italian city, Galileo learned, opposed the entry of natural sisters into the same monastery, but he would not send the girls to another city. He preferred to keep them close by, even if that meant seeking special dispensations.

  “In answer to your letter concerning your daughters’ claustration,” Francesco Maria Cardinal del Monte wrote to Galileo in December of 1611,

  I had fully understood that you did not wish them to take the vei
l immediately, but that you wished them to be received on the understanding that they were to assume the religious habit as soon as they had reached the canonical age. But, as I have written to you before, even this is not allowed, for many reasons: in particular, that it might give rise to the exercise of undue influence by those who wished the young persons to take the veil for reasons of their own. This rule is never broken, and never will be, by the Sacred Congregation. When they have reached the canonical age, they may be accepted with the ordinary dowry, unless the sisterhood already has the prescribed number; if such be the case, it will be necessary to double the dowry. Vacancies may not be filled up by anticipation under severe penalties, that of deprivation for the Abbess in particular, as you may see in a Decretal of Pope Clement of the year 1604.

  It could never be done, but it happened all the time, as Galileo was well aware. If Cardinal del Monte, who had finessed Galileo’s first teaching appointment at Pisa, proved unwilling or unable to get the two girls into one convent before either of them turned sixteen, then some other contact might yet intervene.

  As he neared completion of his treatise on floating bodies, Galileo penned an explanation to the grand duke and the general public as to why his new book concerned bodies in water, instead of continuing the great chain of astronomical discoveries trumpeted in The Starry Messenger. Lest anyone think he had dropped his celestial observations or pursued them too slowly, he could account for his time. “A delay has been caused not merely by the discoveries of three-bodied Saturn and those changes of shape by Venus resembling the moon’s, along with consequences that follow thereon,” Galileo wrote in the introduction, “but also by the investigation of the times of revolution around Jupiter of each of the four Medicean planets, which I managed in April of the past year, 1611, while I was at Rome. . . . I add to these things the observation of some dark spots that are seen in the Sun’s body. . . . Continued observations have finally assured me that such spots are . . . carried around by rotation of the Sun itself, which completes its period in about a lunar month—a great event, and even greater for its consequences.”