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GALILEO GALILEI (1564-1642)
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GALILEO GALILEI (1564-1642) , See also:Italian astronomer and experimental philosopher, was See also:born at See also:Pisa on the 15th of See also:February 1564 . His See also:father, Vincenzio, was an impoverished descendant of a See also:noble Florentine See also:house, which had exchanged the surname of Bonajuti for that of Galilei, on the See also:election, in 1343, of one of its members, Tommaso de' Bonajuti, to the See also:college of the twelve Buonuomini . The See also:family, which was nineteen times represented in the signoria, and in 1445 gave a gonfalonier to See also:Florence, flourished with the See also:republic and declined with its fall . Vincenzio Galilei was a See also:man of better parts than See also:fortune . He was a competent mathematician, wrote with considerable ability on the theory and practice of See also:music, and was especially distinguished amongst his contemporaries for the See also:grace and skill of his performance upon the See also:lute . By his wife, Giulia Ammannati of See also:Pescia, he had three sons and four daughters . From his earliest childhood Galileo, the eldest of the family, was remarkable for intellectual aptitude as well as for See also:mechanical invention . His favourite pastime was the construction of See also:original and ingenious See also:toy-See also:machines; but his application to See also:literary studies was equally conspicuous . In the monastery of See also:Vallombrosa, near Florence, where his See also:education was principally See also:con-ducted, he not only made himself acquainted with the best Latin authors, but acquired a See also:fair command of the See also:Greek See also:tongue, thus laying the See also:foundation of his brilliant and elegant See also:style . From one of the monks he also received instruction in See also:logic; but the subtleties of the scholastic See also:science were thoroughly distasteful to him . A document published by F . Selmi in 1864 proves that he was at this See also:time so far attracted towards a religious See also:life as to have joined the novitiate; but his father, who had other designs for him, seized the opportunity of an attack of ophthalmia to withdraw him permanently from the care of the monks . Having had See also:personal experience of the unremunerative See also:character both of music and of See also:mathematics, he desired that his son should apply himself to the cultivation of See also:medicine, and, not without some straining of his slender resources, placed him, before he had completed his eighteenth See also:year, at the university of Pisa . He accordingly matriculated there on the 5th of See also:November 1581, and immediately entered upon attendance at the lectures of the, celebrated physician and botanist, See also:Andrea Cesalpino . The natural gifts of the See also:young student seemed at this time equally ready to develop in any direction towards which choice or See also:hazard might incline them . In musical skill and invention he already vied with the best professors of the See also:art in See also:Italy; his personal See also:taste would have led him to choose See also:painting as his profession, and one of the most eminent artists of his See also:day, Lodovico See also:Cigoli, owned that to his See also:judgment and counsel he wasmainly indebted for the success of his See also:works . In 1581, while watching a See also:lamp set swinging in the See also:cathedral of Pisa, he observed that, whatever the range of its oscillations, they were invariably executed in equal times . The experimental verification of this fact led him to the important See also:discovery of the isochronism of the pendulum . He at first applied the new principle to See also:pulse-measurement, and more than fifty years later turned it to See also:account in the construction of an astronomical See also:clock . Up to this time he was entirely ignorant of mathematics, his father having carefully held him aloof from a study which he rightly apprehended would See also:lead to his See also:total See also:alienation from that of medicine . See also:Accident, however, frustrated this purpose . A See also:lesson in See also:geometry, given by Ostilio See also:Ricci to the pages of the See also:grand-ducal See also:court, chanced, tradition avers, to have Galileo for an unseen listener; his See also:attention was riveted, his dormant See also:genius was roused, and he threw all his energies into the new pursuit thus unexpectedly presented to him . With Ricci's assistance, he rapidly mastered the elements of the science, and eventually extorted his father's reluctant permission to See also:exchange See also:Hippocrates and See also:Galen for See also:Euclid and See also:Archimedes . In 1585 he was withdrawn from the university, through lack of means, before he had taken a degree, and returned to Florence, where his family habitually resided .
We next hear of him as lecturing before the Florentine See also:Academy on the site and dimensions of See also:Dante's Inferno; and he shortly afterwards published an See also:essay descriptive of his invention of the hydrostatic See also:balance, which rapidly made his name known throughout Italy
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His first See also:patron was the Marchese Guidubaldo del See also:Monte of See also:Pesaro, a man equally eminent in science, and influential through family connexions
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At the Marchese's See also:request he wrote, in 1588, a See also:treatise on the centre of gravity in solids, which obtained for him, together with the See also:title of " the Archimedes of his time," the See also:honourable though not lucrative See also:post of mathematical lecturer at the See also:Pisan university
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During the ensuing two years (1589–1591) he carried on that remarkable See also:series of experiments by which he established the first principles of See also:dynamics and earned the undying hostility of bigoted Aristotelians
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From the leaning See also:tower of Pisa he afforded to all the professors and students of the university ocular demonstration of the falsehood of the Peripatetic dictum that heavy bodies fall with velocities proportional to their weights, and with unanswerable logic demolished all the time-honoured See also:maxims of the See also:schools regarding the See also:motion of projectiles, and elemental See also:weight or levity
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But while he convinced, he failed to conciliate his adversaries
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The keen See also:sarcasm of his polished See also:rhetoric was not calculated to soothe the susceptibilities of men already smarting under the deprivation of their most cherished illusions
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He seems, in addition, to have compromised his position with the grand-ducal family by the imprudent candour with which he condemned a See also:machine for clearing the See also:port of See also:Leghorn, invented by Giovanni de' See also:Medici, an illegitimate son of Cosmo I
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Princely favour being withdrawn, private rancour was See also:free to show itself
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He was publicly hissed at his lecture, and found it prudent to resign his professorship and withdraw to Florence in 1591
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Through the See also:death of his father in See also:July of that year family cares and responsibilities devolved upon him, and thus his nomination to the See also:chair of mathematics at the university of See also:Padua, secured by the See also:influence of the Marchese Guidubaldo with the Venetian See also:senate, was welcome both as affording a See also:relief from pecuniary embarrassment and as opening a See also:
His See also:appointment was three times renewed, on each occasion with the expressions of the highest esteem on the See also:part of the governing See also:body, and his yearly See also:salary was progressively raised from 18o to l000 florins
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His lectures were attended by persons of the highest distinction from all parts of See also:Europe, and such was the See also:charm of his demonstrations that a See also: Discoveries followed upon it with astounding rapidity and in bewildering variety . The Sidereus Nuncios, published at Venice early in 161o, contained the first-fruits of the new mode of investigation, which were sufficient to excite learned amazement on both sides of the See also:Alps . The mountainous configuration of the See also:moon's See also:surface was there first described, and the so-called " See also:phosphorescence " of the dark portion of our See also:satellite attributed to its true cause—namely, See also:illumination by sunlight reflected from the See also:earth .2 All the time-worn fables and conjectures regarding the composition of the Milky Way were at once dissipated by the simple statement that to the See also:eye, reinforced by the telescope, it appeared as a congeries of lesser stars, while the See also:great nebulae were equally declared to be resolvable into similar elements . But the discovery which was at once perceived to be most important in itself, and most revolutionary in its effects, was that of See also:Jupiter's satellites, first seen by Galileo on the 7th of See also:January 161o, and by him named Sidera Medicea, in honour of the grand-See also:duke of See also:Tuscany, Cosmo II., who had been his See also:pupil, and was about to become his employer . An See also:illustration is, with the general run of mankind, more powerful to convince than an See also:argument; and the cogency of the visible plea for the Copernican theory offered by the See also:miniature system, then first disclosed to view, was recognizable in the See also:triumph of its See also:advocates as well as in the increased acrimony of its opponents . In September 16ro Galileo finally abandoned Padua for Florence . His researches with the telescope had been rewarded ' The word telescope, from riPte, far, eKmreiv, to view, was invented by Demiscianus, an eminent Greek See also:scholar, at the request of See also:Prince Cesi, See also:president of the Lyncean Academy . It was used by Galileo as early as 1612, but was not introduced into See also:England until much later . In 1655 the word telescope was inserted and explained in Bagwell's Mysteries of Astronomy, See also:trunk or See also:cylinder being the terms until then ordinarily employed . 2 Leonardo da See also:Vinci, more than a See also:hundred years earlier, had come to the same conclusion.by the Venetian senate with the appointment for life to his professorship, at an unprecedentedly high salary . His discovery of the " Medicean Stars " was acknowledged by his nomination (July 12, 161o) as philosopher and mathematician extraordinary to the grand-duke of Tuscany . The emoluments of this See also:office, which involved no duties See also:save that of continuing his scientific labours, were fixed at r000 scudi; and it was the See also:desire of increased leisure, rather than the promptings of See also:local patriotism, which induced him to accept an offer the original See also:suggestion of which had indeed come from himself .
Before the See also:close of 16ro the memorable See also:cycle of discoveries begun in the previous year was completed by the observation of the ansated or, as it appeared to Galileo, triple See also:form of See also:Saturn (the See also:ring-formation was first recognized by Christiaan See also:Huygens in 1655), of the phases of See also:Venus, and of the spots upon the See also:sun
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As regards sun-spots, however, Johann See also:Fabricius of Osteel in See also:Friesland can claim priority of publication, if not of actual detection
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In the See also:spring of 1611 Galileo visited See also:Rome, and exhibited in the gardens of the Quirinal See also:Palace the telescopic wonders of the heavens to the most eminent personages at the pontifical court
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Encouraged by the flattering reception accorded to him, he ventured, in his Letters on the Solar Spots, printed at Rome in 1613, to take up a more decided position towards that See also:doctrine on the See also:establishment of which, as he avowed in a letter to Belisario Vinta, secretary to the grand-duke, " all his life and being henceforward depended." Even in the time of See also:Copernicus some well-meaning persons, especially those of the reformed persuasion, had suspected a discrepancy between the new view of the solar system and certain passages of Scripture—a suspicion strengthened by the See also:anti-See also:Christian inferences See also:drawn from it by See also:Giordano See also:Brune; but the question was never formally debated until Galileo's brilliant disclosures, enhanced by his formidable See also:dialectic and enthusiastic zeal, irresistibly challenged for it the attention of the authorities
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Although he had no desire to raise the theological issue, it must be admitted that, the discussion once set on See also:foot, he threw himself into it with characteristic impetuosity, and thus helped to precipitate a decision which it was his See also:interest to avert
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In See also:December 1613 a See also:Benedictine See also:
He was a man of vast learning and upright piety, but, although personalty friendly to Galileo, there is no doubt that he saw in his scientific teachings a danger to See also:religion
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The year 1615 seems to have been a period of suspense
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Galileo received, as the result of a See also:conference between Cardinals Bellarmin and Del Monte, a semi-See also:official warning to avoid See also:theology, and limit himself to physical reasoning
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" Write freely," he was told by See also:Monsignor Dini, " but keep outside the
See also:sacristy." Unfortunately, he had already committed himself to dangerous ground
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In December he repaired personally to Rome, full of confidence that the weight of his arguments and the vivacity of his eloquence could not fail to convert the entire pontifical court to his views
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He was cordially received, and eagerly listened to, but his imprudent ardour served but to injure his cause
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On the 24th of February 1616 the consulting theologians of the Holy Office characterized the two propositions—that the sun is immovable in the centre of the See also:world, and that the earth has a diurnal motion of rotation—the first as " absurd in See also:philosophy, and formally heretical, because expressly contrary to Holy Scripture," and the second as " open to the same censure in philosophy, and at least erroneous as to faith." Two days later Galileo was, by command of the See also:pope (See also:Paul V.), summoned to the palace of Cardinal Bellarmin, and there officially admonished not thenceforward to " hold, See also:teach or defend " the condemned doctrine
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This See also:injunction he promised to obey
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On the 5th of See also: He brought with him, for the refutation of calumnious reports circulated by his enemies, a written certificate from Cardinal Bellarmin, to the effect that no See also:abjuration had been required of or See also:penance imposed upon him . During a prolonged See also:audience he had received from the pope assurances of private esteem and personal See also:protection; and he trusted to his dialectical ingenuity to find the means of presenting his scientific convictions under the trans-See also:parent See also:veil of an See also:hypothesis . Although a sincere See also:Catholic, he seems to have laid but little stress on the See also:secret admonition of the Holy Office, which his sanguine temperament encouraged him gradually to dismiss from his mind . He preserved no written memorandum of its terms, and it was represented to him, according to his own deposition in 1633, solely by Cardinal Bellarmin's certificate, in which, for obvious reasons, it was glossed over rather than expressly recorded . For seven years, nevertheless, during which he led a life of studious retirement in the See also:Villa Segni at Bellosguardo, near Florence, he maintained an almost unbroken silence . At the end of that time he appeared in public with his Saggiatore, a polemical treatise written in reply to the See also:Libra astronomica of Padre Grassi (under the See also:pseudonym of Lotario Sarsi), the Jesuit astronomer of the Collegio Romano . The subject in debate was the nature of comets,. the conspicuous appearance of three of which bodies in the year 1618 furnished the occasion of the controversy . Galileo's views, although erroneous, since he held comets to be See also:mere atmospheric emanations reflecting sunlight after the evanescent See also:fashion of a See also:halo or a See also:rainbow, were expressed with such triumphant vigour, and embellished with such telling sarcasms, that his opponent did not venture upon a reply . The Saggiatore was printed at Rome in October 1623 by the Academy of the Lincei, of which Galileo was, a member, with a See also:dedication to the new pope, See also:Urban VIII., and notwithstanding some passages containing a covert See also:defence of Copernican opinions, was received-with See also:acclamation by ecclesiastical, no less than by scientific authorities . Everything seemed now to promise a close of unbroken prosperity to Galileo's career . Maffeo See also:Barberini, his warmest friend and admirer in the Sacred College, was, by the election of: the 8th of August 1623, seated on the pontifical See also:throne; and themarked distinction with which he was received on his visit of congratulation to Rome in 1624 encouraged him to See also:hope for the realization of his utmost wishes . He received every See also:mark of private favour . The pope admitted him to six See also:long audiences in the course of two .months, wrote an enthusiastic letter to the grand-duke praising the great astronomer, not only for his distinguished learning, but also for his exemplary piety, and granted a See also:pension to his son Vincenzio, which was afterwards transferred to himself, and paid, with some irregularities, to the end of his life . But on the subject of the decree of 1616, the revocation of which Galileo had hoped to obtain through his personal influence, he found him inexorable . Yet there seemed See also:reason to expect that it would at least be interpreted.in a liberal spirit, and Galileo's See also:friends encouraged his imprudent confidence by eagerly retailing to him every papal utterance which it was possible to construe in a favourable sense . To Cardinal See also:Hohenzollern, Urban was reported to have said that the theory of the earth's motion had not been and could not be condemned as heretical, but only as rash; and in 163o the brilliant Dominican monk Tommaso See also:Campanella wrote to Galileo that the pope had expressed to him in conversation his disapproval of the prohibitory decree . Thus, in the full anticipation of added renown, and without any misgiving as to ulterior consequences, Galileo set himself, on his return to Florence, to See also:complete his famous but ill-starred work, the Dialogo dei due massimi sistemi del mondo . Finished in 163o, it was not until January 1632 that it emerged from the presses of Landini at Florence . The book was originally intended to appear in Rome, but unexpected obstacles interposed . The Lincean Academy collapsed with the death of Prince Federigo Cesi, its founder and president; an outbreak of See also:plague impeded communication between the various Italian cities; and the imprimatur was finally extorted, rather than accorded, under the pressure of private friendship and powerful interest . A tumult of See also:applause from every part of Europe followed its publication; and it would be difficult to find in any See also:language a book in which animation and elegance of style are so happily combined with strength and clearness of scientific exposition . Three interlocutors, named respectively Salviati, Sagredo, and Simplicio, take part in the four dialogues of which the work is composed . The first-named expounds the views of the author; the second is an eager and intelligent listener; the third represents a well-meaning but obtuse Peripatetic, whom the others treat at times with undisguised contempt . Salviati and Sagredo took their names from two of Galileo's early friends, the former a learned Florentine, the latter a distinguished Venetian See also:gentleman; Simplicio ostensibly derived his from the Cilician commentator of See also:Aristotle, but the choice was doubtless instigated by a sarcastic regard to the See also:double meaning of the word . 
There were not wanting those who insinuated that Galileo intended to depict the pope himself in the See also:guise of the simpleton of the party; and the See also:charge, though preposterous in itself, was supported by certain imprudences of expression, which Urban was not permitted to ignore . It was at once evident that the whole See also:tenor of this remarkable work was in flagrant See also:contradiction with the edict passed sixteen years before its publication, as well as with the author's personal See also:pledge of conformity to it . The ironical submission with which it opened, and the assumed indetermination with which it closed, were hardly intended to See also:mask the vigorous assertion of Copernican principles which formed its substance . It is a singular circumstance, however, that the argument upon which Galileo mainly relied as furnishing a physical demonstration of the truth of the new theory rested on a misconception . The ebb and flow of the tides were, he asserted, a visible See also:proof of the terrestrial double See also:movement, since they resulted from inequalities in the See also:absolute velocities through space of the various parts of the earth's surface, due to its rotation . To this notion, which took its rise in a confusion of thought, he attached See also:capital importance, and he treated with scorn Kepler's suggestion that a certain occult attraction of the moon was in some way concerned in the phenomenon . The theological censures which the book did not fail to incur were not slow in making themselves See also:felt . Towards the end of August the See also: |