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.
Before leaving Rome triumphant at the end of May, Galileo gained a favourable 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 autumn, in Florence, when the visiting cardinal was the grand duke’s dinner guest, and Galileo the after-dinner entertainment. On that night, 2 October 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 under water 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 per cent 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, eleven and ten, 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 sanatorium 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 elder 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 veil 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