Table of Contents



Peculiar interest attached to his Life—His Birth—His early studies—His passion for Mathematics—His work on the Hydrostatic Balance—Appointed Lecturer on Mathematics at Pisa—His antipathy to the Philosophy of Aristotle—His contentions with the Aristotelians—Chosen professor of Mathematics in Padua—Adopts the Copernican system, but still teaches the Ptolemaic doctrine—His alarming illness—He observes the new Star in 1604—His magnetical experiments.

The history of the life and labours of Galileo is pregnant with a peculiar interest to the general reader, as well as to the philosopher. His brilliant discoveries, the man of science regards as his peculiar property; the means by which they were made, and the development of his intellectual character, belong to the logician and to the philosopher; but the triumphs and the reverses of his eventful life must be claimed for our common nature, as a source of more than ordinary instruction.


The lengthened career which Providence assigned to Galileo was filled up throughout its rugged outline with events even of dramatic interest. But though it was emblazoned with achievements of transcendent magnitude, yet his noblest discoveries were the derision of his contemporaries, and were even denounced as crimes which merited the vengeance of Heaven. Though he was the idol of his friends, and the favoured companion of princes, yet he afterwards became the victim of persecution, and spent some of his last hours within the walls of a prison; and though the Almighty granted him, as it were, a new sight to descry unknown worlds in the obscurity of space, yet the eyes which were allowed to witness such wonders, were themselves doomed to be closed in darkness.

Such were the lights and shadows in which history delineates

But, however powerful be their contrasts, they are not unusual in their proportions. The balance which has been struck between his days of good and evil, is that which regulates the lot of man, whether we study it in the despotic sway of the autocrat, in the peaceful inquiries of the philosopher, or in the humbler toils of ordinary life.

Galileo Galilei was born at Pisa, on the 15th of February, 1564, and was the eldest of a family of three sons and three daughters. Under the name of Bonajuti, his noble ancestors had filled high offices at Florence; but about the middle of the 14th century they seem to have abandoned this surname for that of Galileo. Vincenzo Galilei, our author’s father, was himself a philosopher of no mean powers; and though his talents seem to have been exercised only in the composition of treatises on the theory and practice of music, yet he appears to have anticipated even his son in a just estimate of the philosophy of the age, and in a distinct perception of the true method of investigating truth.[2]

The early years of Galileo were, like those of almost all great experimental philosophers, spent in the construction of instruments and pieces of machinery, which were calculated chiefly to amuse himself and his schoolfellows. This employment of his hands, however, did not interfere with his regular studies; and though, from the straitened circumstances of his father, he was educated under considerable disadvantages, yet he acquired the elements of classical literature, and was initiated into all the learning of the times. Music, drawing, and painting were the occupations of his leisure hours; and such was his proficiency in these arts, that he was reckoned a skilful performer on several musical instruments, especially the lute; and his knowledge of pictures was held in great esteem by some of the best artists of his day.

Galileo seems to have been desirous of following the profession of a painter: but his father had observed decided indications of early genius; and, though by no means able to afford it, he resolved to send him to the university to pursue the study of medicine. He accordingly enrolled himself as a scholar in arts at the university of Pisa, on the 5th of November, 1581, and pursued his medical studies under the celebrated botanist Andrew Cæsalpinus, who filled the chair of medicine from 1567 to 1592.

In order to study the principles of music and drawing, Galileo found it necessary to acquire some knowledge of geometry. His father seems to have foreseen the consequences of following this new pursuit, and though he did not prohibit him from reading Euclid under Ostilio Ricci, one of the professors at Pisa, yet he watched his progress with the utmost jealousy, and had resolved that it should not interfere with his medical studies. The demonstrations, however, of the Greek mathematician had too many charms for the ardent mind of Galileo. His whole attention was engrossed with the new truths which burst upon his understanding; and after many fruitless attempts to check his ardour and direct his thoughts to professional objects, his father was obliged to surrender his parental control, and allow the fullest scope to the genius of his son.

From the elementary works of geometry, Galileo passed to the writings of Archimedes; and while he was studying the hydrostatical treatise[3] of the Syracusan philosopher, he wrote his essay on the hydrostatical balance,[4] in which he describes the construction of the instrument, and the method by which Archimedes detected the fraud committed by the jeweller in the composition of Hiero’s crown. This work gained for its author the esteem of Guido Ubaldi, who had distinguished himself by his mechanical and mathematical acquirements, and who engaged his young friend to investigate the subject of the centre of gravity in solid bodies. The treatise on this subject, which Galileo presented to his patron, proved the source of his future success in life.

Through the Cardinal del Monte, the brother-in-law of Ubaldi, the reigning Duke of Tuscany, Ferdinand de Medici was made acquainted with the merits of our young philosopher; and, in 1589, he was appointed lecturer on mathematics at Pisa. As the salary, however, attached to this office was only sixty crowns, he was compelled to enlarge this inadequate income by the additional occupation of private teaching, and thus to encroach upon the leisure which he was anxious to devote to science.

With this moderate competency, Galileo commenced his philosophical career. At the early age of eighteen, when he had entered the university, his innate antipathy to the Aristotelian philosophy began to display itself. This feeling was strengthened by his earliest inquiries; and upon his establishment at Pisa he seems to have regarded the doctrines of Aristotle as the intellectual prey which, in his chace of glory, he was destined to pursue. Nizzoli, who flourished near the beginning of the sixteenth century, and Giordano Bruno, who was burned at Rome in 1600, led the way in this daring pursuit; but it was reserved for Galileo to track the Thracian boar through its native thickets, and, at the risk of his own life, to strangle it in its den.

With the resolution of submitting every opinion to the test of experiment, Galileo’s first inquiries at Pisa were directed to the mechanical doctrines of Aristotle. Their incorrectness and absurdity soon became apparent; and with a zeal, perhaps, bordering on indiscretion, he denounced them to his pupils with an ardour of manner and of expression proportioned to his own conviction of the truth. The detection of long-established errors is apt to inspire the young philosopher with an exultation which reason condemns. The feeling of triumph is apt to clothe itself in the language of asperity; and the abettor of erroneous opinions is treated as a species of enemy to science. Like the soldier who fleshes his first spear in battle, the philosopher is apt to leave the stain of cruelty on his early achievements. It is only from age and experience, indeed, that we can expect the discretion of valour, whether it is called forth in controversy or in battle. Galileo seems to have waged this stern warfare against the followers of Aristotle; and such was the exasperation which was excited by his reiterated and successful attacks, that he was assailed, during the rest of his life, with a degree of rancour which seldom originates in a mere difference of opinion. Forgetting that all knowledge is progressive, and that the errors of one generation call forth the comments, and are replaced by the discoveries, of the next, Galileo did not anticipate that his own speculations and incompleted labours might one day provoke unmitigated censure; and he therefore failed in making allowance for the prejudices and ignorance of his opponents. He who enjoys the proud lot of taking a position in advance of his age, need not wonder that his less gifted contemporaries are left behind. Men are not necessarily obstinate because they cleave to deeply rooted and venerable errors, nor are they absolutely dull when they are long in understanding and slow in embracing newly discovered truths.

It was one of the axioms of the Aristotelian mechanics, that the heavier of two falling bodies would reach the ground sooner than the other, and that their velocities would be proportional to their weights. Galileo attacked the arguments by which this opinion was supported; and when he found his reasoning ineffectual, he appealed to direct experiment. He maintained, that all bodies would fall through the same height in the same time, if they were not unequally retarded by the resistance of the air: and though he performed the experiment with the most satisfactory results, by letting heavy bodies fall from the leaning tower of Pisa, yet the Aristotelians, who with their own eyes saw the unequal weights strike the ground at the same instant, ascribed the effect to some unknown cause, and preferred the decision of their master to that of nature herself.

Galileo could not brook this opposition to his discoveries; nor could the Aristotelians tolerate the rebukes of their young instructor. The two parties were, consequently, marshalled in hostile array; when, fortunately for both, an event occurred, which placed them beyond the reach of danger. Don Giovanni de Medici, a natural son of Cosmo, had proposed a method of clearing out the harbour of Leghorn. Galileo, whose opinion was requested, gave such an unfavourable report upon it, that the disappointed inventor directed against him all the force of his malice. It was an easy task to concentrate the malignity of his enemies at Pisa; and so effectually was this accomplished, that Galileo resolved to accept another professorship, to which he had been previously invited.

The chair of mathematics in the university of Padua having been vacant for five years, the republic of Venice had resolved to fill it up; and, on the recommendation of Guido Ubaldi, Galileo was appointed to it, in 1592, for a period of six years.


Previous to this event, Galileo had lost his father, who died, in 1591, at an advanced age. As he was the eldest son, the support of the family naturally devolved upon him; and this sacred obligation must have increased his anxiety to better his circumstances, and therefore added to his other inducements to quit Pisa. In September 1592, he removed to Padua, where he had a salary of only 180 florins, and where he was again obliged to add to his income by the labours of tuition. Notwithstanding this fruitless occupation of his time, he appears to have found leisure for composing several of his works, and completing various inventions, which will be afterwards described. His manuscripts were circulated privately among his friends and pupils; but some of them strayed beyond this sacred limit, and found their way into the hands of persons, who did not scruple to claim and publish, as their own, the discoveries and inventions which they contained.

It is not easy to ascertain the exact time when Galileo became a convert to the doctrines of Copernicus, or the particular circumstances under which he was led to adopt them. It is stated by Gerard Voss, that a public lecture of Mœstlin, the instructor of Kepler, was the means of making Galileo acquainted with the true system of the universe. This assertion, however, is by no means probable; and it has been ably shown, by the latest biographer of Galileo,[5] that, in his dialogues on the Copernican system, our author gives the true account of his own conversion. This passage is so interesting, that we shall give it entire.

“I cannot omit this opportunity of relating to you what happened to myself at the time when this opinion (the Copernican system) began to be discussed. I was then a very young man, and had scarcely finished my course of philosophy, which other occupations obliged me to leave off, when there arrived in this country, from Rostoch, a foreigner, whose name, I believe, was Christian Vurstisius (Wurteisen), a follower of Copernicus. This person delivered, on this subject, two or three lectures in a certain academy, and to a crowded audience. Believing that several were attracted more by the novelty of the subject than by any other cause, and being firmly persuaded that this opinion was a piece of solemn folly, I was unwilling to be present. Upon interrogating, however, some of those who were there, I found that they all made it a subject of merriment, with the exception of one, who assured me that it was not a thing wholly ridiculous. As I considered this individual to be both prudent and circumspect, I repented that I had not attended the lectures; and, whenever I met any of the followers of Copernicus, I began to inquire if they had always been of the same opinion. I found that there was not one of them who did not declare that he had long maintained the very opposite opinions, and had not gone over to the new doctrines till he was driven by the force of argument. I next examined them one by one, to see if they were masters of the arguments on the opposite side; and such was the readiness of their answers, that I was satisfied they had not taken up this opinion from ignorance or vanity. On the other hand, whenever I interrogated the Peripatetics and the Ptolemeans—and, out of curiosity, I have interrogated not a few—respecting their perusal of Copernicus’s work, I perceived that there were few who had seen the book, and not one who understood it. Nor have I omitted to inquire among the followers of the Peripatetic doctrines, if any of them had ever stood on the opposite side; and the result was, that there was not one. Considering, then, that nobody followed the Copernican doctrine, who had not previously held the contrary opinion, and who was not well acquainted with the arguments of Aristotle and Ptolemy; while, on the other hand, nobody followed Ptolemy and Aristotle, who had before adhered to Copernicus, and had gone over from him into the camp of Aristotle;—weighing, I say, these things, I began to believe that, if any one who rejects an opinion which he has imbibed with his milk, and which has been embraced by an infinite number, shall take up an opinion held only by a few, condemned by all the schools, and really regarded as a great paradox, it cannot be doubted that he must have been induced, not to say driven, to embrace it by the most cogent arguments. On this account I have become very curious to penetrate to the very bottom of the subject.”[6]


It appears, on the testimony of Galileo himself, that he taught the Ptolemaic system, in compliance with the popular feeling, after he had convinced himself of the truth of the Copernican doctrines. In the treatise on the sphere, indeed, which bears his name,[7] and which must have been written soon after he went to Padua, and subsequently to 1592, the stability of the earth, and the motion of the sun, are supported by the very arguments which Galileo afterwards ridiculed; but we have no means of determining whether or not he had then adopted the true system of the universe. Although he might have taught the Ptolemaic system in his lectures after he had convinced himself of its falsehood, yet it is not likely that he would go so far as to publish to the world, as true, the very doctrines which he despised. In a letter to Kepler, dated in 1597, he distinctly states that he had, many years ago, adopted the opinions of Copernicus; but that he had not yet dared to publish his arguments in favour of them, and his refutation of the opposite opinions. These facts would leave us to place Galileo’s conversion somewhere between 1593 and 1597, although many years cannot be said to have elapsed between these two dates.


At this early period of Galileo’s life, in the year 1593, he met with an accident which had nearly proved fatal. A party at Padua, of which he was one, were enjoying, at an open window, a current of air, which was artificially cooled by a fall of water. Galileo unfortunately fell asleep under its influence; and so powerful was its effect upon his robust constitution, that he contracted a severe chronic disorder, accompanied with acute pains in his body, and loss of sleep and appetite, which attacked him at intervals during the rest of his life. Others of the party suffered still more severely, and perished by their own rashness.

Galileo’s reputation was now widely extended over Europe. The Archduke Ferdinand (afterwards Emperor of Germany), the Landgrave of Hesse, and the Princes of Alsace and Mantua, honoured his lectures with their presence; and Prince Gustavus Adolphus of Sweden also received instructions from him in mathematics, during his sojourn in Italy.

When Galileo had completed the first period of his engagement at Padua, he was re-elected for other six years, with an increased salary of 320 florins. This liberal addition to his income is ascribed by Fabbroni to the malice of one of his enemies, who informed the Senate that Galileo was living in illicit intercourse with Marina Gamba. Without inquiring into the truth of the accusation, the Senate is said to have replied, that if “he had a family to support, he had the more need of an increased salary.” It is more likely that the liberality of the republic had been called forth by the high reputation of their professor, and that the terms of their reply were intended only to rebuke the malignity of the informer. The mode of expression would seem to indicate that one or more of Galileo’s children had been born previous to his re-election in 1598; but as this is scarcely consistent with other facts, we are disposed to doubt the authenticity of Fabbroni’s anecdote.

The new star which attracted the notice of astronomers in 1604, excited the particular attention of Galileo. The observations which he made upon it, and the speculations which they suggested, formed the subject of three lectures, the beginning of the first of which only has reached our times. From the absence of parallax, he proved that the common hypothesis of its being a meteor was erroneous, and that, like the fixed stars, it was situated far beyond the bounds of our own system. The popularity of the subject attracted crowds to his lecture-room; and Galileo had the boldness to reproach his hearers for taking so deep an interest in a temporary phenomenon, while they overlooked the wonders of creation which were daily presented to their view.

In the year 1606, Galileo was again appointed to the professorship at Padua, with an augmented stipend of 520 florins. His popularity had now risen so high, that his audience could not be accommodated in his lecture-room; and even when he had assembled them in the school of medicine, which contained 1000 persons, he was frequently obliged to adjourn to the open air.

Among the variety of pursuits which occupied his attention, was the examination of the properties of the loadstone. In 1607, he commenced his experiments; but, with the exception of a method of arming loadstones, which, according to the report of Sir Kenelm Digby, enabled them to carry twice as much weight as before, he does not seem to have made any additions to our knowledge of magnetism. He appears to have studied with care the admirable work of our countryman, Dr Gilbert, “De Magnete,” which was published in 1600; and he recognised in the experiments and reasonings of the English philosopher the principles of that method of investigating truth which he had himself adopted. Gilbert died in 1603, in the 63d year of his age, and probably never read the fine compliment which was paid to him by the Italian philosopher—“I extremely praise, admire, and envy this author.”


Cosmo, Grand Duke of Tuscany, invites Galileo to Pisa—Galileo visits Venice in 1609, where he first hears of the Telescope—He invents and constructs one, which excites a great sensation—Discovers Mountains in the Moon, and Forty Stars in the Pleiades—Discovers Jupiter’s Satellites in 1610—Effect of this discovery on Kepler—Manner in which these discoveries were received—Galileo appointed Mathematician to Cosmo—Mayer claims the discovery of the Satellites of Jupiter—Harriot observes them in England in October 1610.

In the preceding chapter we have brought down the history of Galileo’s labours to that auspicious year in which he first directed the telescope to the heavens. No sooner was that noble instrument placed in his hands, than Providence released him from his professional toils, and supplied him with the fullest leisure and the amplest means for pursuing and completing the grandest discoveries.


Although he had quitted the service and the domains of his munificent patron, the Grand Duke of Tuscany, yet he maintained his connection with the family, by visiting Florence during his academic vacations, and giving mathematical instruction to the younger branches of that distinguished house. Cosmo, who had been one of his pupils, now succeeded his father Ferdinand; and having his mind early imbued with a love of knowledge, which had become hereditary in his family, he felt that the residence of Galileo within his dominions, and still more his introduction into his household, would do honour to their common country, and reflect a lustre upon his own name. In the year 1609, accordingly, Cosmo made proposals to Galileo to return to his original situation at Pisa. These overtures were gratefully received; and in the arrangements which Galileo on this occasion suggested, as well as in the manner in which they were urged, we obtain some insight into his temper and character. He informs the correspondent through whom Cosmo’s offer was conveyed, that his salary of 520 florins at Padua would be increased to as many crowns at his re-election, and that he could enlarge his income to any extent he pleased, by giving private lectures and receiving pupils. His public duties, he stated, occupied him only sixty half-hours in the year; but his studies suffered such interruptions from his domestic pupils and private lectures, that his most ardent wish was to be relieved from them, in order that he might have sufficient rest and leisure, before the close of his life, to finish and publish those great works which he had projected. In the event, therefore, of his returning to Pisa, he hoped that it would be the first object of his serene highness to give him leisure to complete his works without the drudgery of lecturing. He expresses his anxiety to gain his bread by his writings, and he promises to dedicate them to his serene master. He enumerates, among these books, two on the system of the universe, three on local motion, three books of mechanics, two on the demonstration of principles, and one of problems; besides treatises on sound and speech, on light and colours, on the tides, on the composition of continuous quantity, on the motions of animals, and on the military art. On the subject of his salary, he makes the following curious observations:—

“I say nothing,” says he, “on the amount of my salary; being convinced that, as I am to live upon it, the graciousness of his highness would not deprive me of any of those comforts, of which, however, I feel the want of less than many others; and, therefore, I say nothing more on the subject. Finally, on the title and profession of my service, I should wish that, to the title of mathematician, his highness would add that of philosopher, as I profess to have studied a greater number of years in philosophy, than months in pure mathematics; and how I have profited by it, and if I can or ought to deserve this title, I may let their highnesses see, as often as it shall please them to give me an opportunity of discussing such subjects in their presence with those who are most esteemed in this knowledge.”

During the progress of this negotiation, Galileo went to Venice, on a visit to a friend, in the month of April or May 1609. Here he learned, from common rumour, that a Dutchman had presented to prince Maurice of Nassau an optical instrument, which possessed the singular property of causing distant objects to appear nearer the observer. This Dutchman was Hans or John Lippershey, who, as has been clearly proved by the late Professor Moll of Utrecht,[8] was in the possession of a telescope made by himself so early as 2d October 1608. A few days afterwards, the truth of this report was confirmed by a letter which Galileo received from James Badorere at Paris, and he immediately applied himself to the consideration of the subject. On the first night after his return to Padua, he found, in the doctrines of refraction, the principle which he sought. He placed at the ends of a leaden tube two spectacle glasses, both of which were plain on one side, while one of them had its other side convex, and the other its second side concave, and having applied his eye to the concave glass, he saw objects pretty large and pretty near him. This little instrument, which magnified only three times, he carried in triumph to Venice, where it excited the most intense interest. Crowds of the principal citizens flocked to his house to see the magical toy; and after nearly a month had been spent in gratifying this epidemical curiosity, Galileo was led to understand from Leonardo Deodati, the Doge of Venice, that the senate would be highly gratified by obtaining possession of so extraordinary an instrument. Galileo instantly complied with the wishes of his patrons, who acknowledged the present by a mandate conferring upon him for life his professorship at Padua, and generously raising his salary from 520 to 1000 florins.[9]


Although we cannot doubt the veracity of Galileo, when he affirms that he had never seen any of the Dutch telescopes, yet it is expressly stated by Fuccarius, that one of these instruments had at this time been brought to Florence; and Sirturus assures us that a Frenchman, calling himself a partner of the Dutch inventor, came to Milan in May 1609, and offered a telescope to the Count de Fuentes. In a letter from Lorenzo Pignoria to Paolo Gualdo, dated from Padua, on the 31st of August 1609, it is expressly said, that, at the re-election of the professors, Galileo had contrived to obtain 1000 florins for life, which was alleged to be on account of an eye-glass like the one which was sent from Flanders to the Cardinal Borghese.

In a memoir so brief and general as the present, it would be out of place to discuss the history of this extraordinary invention. We have no hesitation in asserting that a method of magnifying distant objects was known to Baptista Porta and others; but it seems to be equally certain that an instrument for producing these effects was first constructed in Holland, and that it was from that kingdom that Galileo derived the knowledge of its existence. In considering the contending claims, which have been urged with all the ardour and partiality of national feeling, it has been generally overlooked, that a single convex lens, whose focal length exceeds the distance at which we examine minute objects, performs the part of a telescope, when an eye, placed behind it, sees distinctly the inverted image which it forms. A lens, twenty feet in focal length, will in this manner magnify twenty times; and it was by the same principle that Sir William Herschel discovered a new satellite of Saturn, by using only the mirror of his forty-feet telescope. The instrument presented to Prince Maurice, and which the Marquis Spinola found in the shop of John Lippershey, the spectacle maker of Middleburg, must have been an astronomical telescope consisting of two convex lenses. Upon this supposition, it differed from that which Galileo constructed; and the Italian philosopher will be justly entitled to the honour of having invented that form of the telescope which still bears his name, while we must accord to the Dutch optician the honour of having previously invented the astronomical telescope.

The interest which the exhibition of the telescope excited at Venice did not soon subside: Sirturi[10] describes it as amounting almost to phrensy. When he himself had succeeded in making one of these instruments, he ascended the tower of St Mark, where he might use it without molestation. He was recognised, however, by a crowd in the street; and such was the eagerness of their curiosity, that they took possession of the wondrous tube, and detained the impatient philosopher for several hours, till they had successively witnessed its effects. Desirous of obtaining the same gratification for their friends, they endeavoured to learn the name of the inn at which he lodged; but Sirturi fortunately overheard their inquiries, and quitted Venice early next morning, in order to avoid a second visitation of this new school of philosophers. The opticians speedily availed themselves of the new instrument. Galileo’s tube,—or the double eye-glass, or the cylinder, or the trunk, as it was then called, for Demisiano had not yet given it the appellation of telescope,—was manufactured in great quantities, and in a very superior manner. The instruments were purchased merely as philosophical toys, and were carried by travellers into every corner of Europe.

The art of grinding and polishing lenses was at this time very imperfect. Galileo, and those whom he instructed, were alone capable of making tolerable instruments. It appears, from the testimony of Gassendi and Gærtner, that, in 1634, a good telescope could not be procured in Paris, Venice, or Amsterdam; and that, even in 1637, there was not one in Holland which could shew Jupiter’s disc well defined.

After Galileo had completed his first instrument, which magnified only three times, he executed a larger and a better one, with a power of about eight. “At length,” as he himself remarks, “sparing neither labour nor expense,” he constructed an instrument so excellent, that it bore a magnifying power of more than thirty times.

The first celestial object to which Galileo applied his telescope was the moon, which, to use his own words, appeared as near as if it had been distant only two semidiameters of the earth. He then directed it to the planets and the fixed stars, which he frequently observed with “incredible delight.”[11]

The observations which he made upon the moon possessed a high degree of interest. The general resemblance of its surface to that of our own globe naturally fixed his attention; and he was soon able to trace, in almost every part of the lunar disc, ranges of mountains, deep hollows, and other inequalities, which reverberated from their summits and margins the rays of the rising sun, while the intervening hollows were still buried in darkness. The dark and luminous spaces he regarded as indicating seas and continents, which reflected, in different degrees, the incidental light of the sun; and he ascribed the phosphorescence, as it has been improperly called, or the secondary light, which is seen on the dark limb of the moon in her first and last quarters, to the reflection of the sun’s light from the earth.

These discoveries were ill received by the followers of Aristotle. According to their preconceived opinions, the moon was perfectly spherical, and absolutely smooth; and to cover it with mountains, and scoop it out into valleys, was an act of impiety which defaced the regular forms which Nature herself had imprinted. It was in vain that Galileo appealed to the evidence of observation, and to the actual surface of our own globe. The very irregularities on the moon were, in his opinion, the proof of divine wisdom; and had its surface been absolutely smooth, it would have been “but a vast unblessed desert, void of animals, of plants, of cities, and of men—the abode of silence and inaction—senseless, lifeless, soulless, and stripped of all those ornaments which now render it so varied and so beautiful.”

In examining the fixed stars, and comparing them with the planets, Galileo observed a remarkable difference in the appearance of their discs. All the planets appeared with round globular discs like the moon; whereas the fixed stars never exhibited any disc at all, but resembled lucid points sending forth twinkling rays. Stars of all magnitudes he found to have the same appearance; those of the fifth and sixth magnitude having the same character, when seen through a telescope, as Sirius, the largest of the stars, when seen by the naked eye. Upon directing his telescope to nebulæ and clusters of stars, he was delighted to find that they consisted of great numbers of stars which could not be recognised by unassisted vision. He counted no fewer than forty in the cluster called the Pleiades, or Seven Stars; and he has given us drawings of this constellation, as well as of the belt and sword of Orion, and of the nebula of Præsepe. In the great nebula of the Milky Way, he descried crowds of minute stars; and he concluded that this singular portion of the heavens derived its whiteness from still smaller stars, which his telescope was unable to separate.

Important and interesting as these discoveries were, they were thrown into the shade by those to which he was led during an accurate examination of the planets with a more powerful telescope. On the 7th of January 1610, at one o’clock in the morning, when he directed his telescope to Jupiter, he observed three stars near the body of the planet, two being to the east and one to the west of him. They were all in a straight line, and parallel to the ecliptic, and appeared brighter than other stars of the same magnitude. Believing them to be fixed stars, he paid no great attention to their distances from Jupiter and from one another. On the 8th of January, however, when, from some cause or other,[12] he had been led to observe the stars again, he found a very different arrangement of them: all the three were on the west side of Jupiter, nearer one another than before, and almost at equal distances. Though he had not turned his attention to the extraordinary fact of the mutual approach of the stars, yet he began to consider how Jupiter could be found to the east of the three stars, when but the day before he had been to the west of two of them. The only explanation which he could give of this fact was, that the motion of Jupiter was direct, contrary to astronomical calculations, and that he had got before these two stars by his own motion.

In this dilemma between the testimony of his senses and the results of calculation, he waited for the following night with the utmost anxiety; but his hopes were disappointed, for the heavens were wholly veiled in clouds. On the 10th, two only of the stars appeared, and both on the east of the planet. As it was obviously impossible that Jupiter could have advanced from west to east on the 8th of January, and from east to west on the 10th, Galileo was forced to conclude that the phenomenon which he had observed arose from the motion of the stars, and he set himself to observe diligently their change of place. On the 11th, there were still only two stars, and both to the east of Jupiter; but the more eastern star was now twice as large as the other one, though on the preceding night they had been perfectly equal. This fact threw a new light upon Galileo’s difficulties, and he immediately drew the conclusion, which he considered to be indubitable, “that there were in the heavens three stars which revolved round Jupiter, in the same manner as Venus and Mercury revolve round the sun.” On the 12th of January, he again observed them in new positions, and of different magnitudes; and, on the 13th, he discovered a fourth star, which completed the four secondary planets with which Jupiter is surrounded.

Galileo continued his observations on these bodies every clear night till the 22d of March, and studied their motions in reference to fixed stars that were at the same time within the field of his telescope. Having thus clearly established that the four new stars were satellites or moons, which revolved round Jupiter in the same manner as the moon revolves round our own globe, he drew up an account of his discovery, in which he gave to the four new bodies the names of the Medicean Stars, in honour of his patron, Cosmo de Medici, Grand Duke of Tuscany. This work, under the title of “Nuncius Sidereus,” or the “Sidereal Messenger,” was dedicated to the same prince; and the dedication bears the date of the 24th of March, only two days after he concluded his observations.

The importance of this great discovery was instantly felt by the enemies as well as by the friends of the Copernican system. The planets had hitherto been distinguished from the fixed stars only by their relative change of place, but the telescope proved them to be bodies so near to our own globe as to exhibit well-defined discs, while the fixed stars retained, even when magnified, the minuteness of remote and lucid points. The system of Jupiter, illuminated by four moons performing their revolutions in different and regular periods, exhibited to the proud reason of man the comparative insignificance of the globe he inhabits, and proclaimed in impressive language that that globe was not the centre of the universe.

The reception which these discoveries met with from Kepler is highly interesting, and characteristic of the genius of that great man. He was one day sitting idle, and thinking of Galileo, when his friend Wachenfels stopped his carriage at his door, to communicate to him the intelligence. “Such a fit of wonder,” says he, “seized me at a report which seemed to be so very absurd, and I was thrown into such agitation at seeing an old dispute between us decided in this way, that between his joy, my colouring, and the laughter of both, confounded as we were by such a novelty, we were hardly capable, he of speaking, or I of listening. On our parting, I immediately began to think how there could be any addition to the number of the planets without overturning my ‘Cosmographic Mystery,’ according to which Euclid’s five regular solids do not allow more than six planets round the sun.... I am so far from disbelieving the existence of the four circumjovial planets, that I long for a telescope, to anticipate you, if possible, in discovering two round Mars, as the proportion seems to require, six or eight round Saturn, and perhaps one each round Mercury and Venus.”

In a very different spirit did the Aristotelians receive the “Sidereal Messenger” of Galileo. The principal professor of philosophy at Padua resisted Galileo’s repeated and urgent entreaties to look at the moon and planets through his telescope; and he even laboured to convince the Grand Duke that the satellites of Jupiter could not possibly exist. Sizzi, an astronomer of Florence, maintained that as there were only seven apertures in the head—two eyes, two ears, two nostrils, and one mouth—and as there were only seven metals, and seven days in the week, so there could be only seven planets. He seems, however, to have admitted the visibility of the four satellites through the telescope; but he argues, that as they are invisible to the naked eye, they can exercise no influence on the earth; and being useless, they do not therefore exist.

A protegé of Kepler’s, of the name of Horky, wrote a volume against Galileo’s discovery, after having declared, “that he would never concede his four new planets to that Italian from Padua, even if he should die for it.” This resolute Aristotelian was at no loss for arguments. He asserted that he had examined the heavens through Galileo’s own glass, and that no such thing as a satellite existed round Jupiter. He affirmed, that he did not more surely know that he had a soul in his body, than that reflected rays are the sole cause of Galileo’s erroneous observations; and that the only use of the new planets was to gratify Galileo’s thirst for gold, and afford to himself a subject of discussion.

When Horky first presented himself to Kepler, after the publication of this work, the opinion of his patron was announced to him by a burst of indignation which overwhelmed the astonished author. Horky supplicated mercy for his offence; and, as Kepler himself informed Galileo, he took him again into favour, on the condition that Kepler was to show him Jupiter’s satellites, and that Horky was not only to see them, but to admit their existence.

When the spirit of philosophy had thus left the individuals who bore so unworthily her sacred name, it was fortunate for science that it found a refuge among princes. Notwithstanding the reiterated logic of his philosophical professor at Padua, Cosmo de Medici preferred the testimony of his senses to the syllogisms of his instructor. He observed the new planets several times, along with Galileo, at Pisa; and when he parted with him, he gave him a present worth more than 1000 florins, and concluded that liberal arrangement to which we have already referred.

As philosopher and principal mathematician to the Grand Duke of Tuscany, Galileo now took up his residence at Florence, with a salary of 1000 florins. No official duties, excepting that of lecturing occasionally to sovereign princes, were attached to this appointment; and it was expressly stipulated that he should enjoy the most perfect leisure to complete his treatises on the constitution of the universe, on mechanics, and on local motion. The resignation of his professorship in the university of Padua, which was the necessary consequence of his new appointment, created much dissatisfaction: but though many of his former friends refused at first to hold any communication with him, this excitement gradually subsided; and the Venetian senate at last appreciated the feelings, as well as the motives, which induced a stranger to accept of promotion in his native land.

While Galileo was enjoying the reward and the fame of his great discovery, a new species of enmity was roused against him. Simon Mayer, an astronomer of no character, pretended that he had discovered the satellites of Jupiter before Galileo, and that his first observation was made on the 29th of December, 1609. Other astronomers announced the discovery of new satellites: Scheiner reckoned five, Rheita nine, and others found even so many as twelve: these satellites, however, were found to be only fixed stars. The names of Vladislavian, Agrippine, Uranodavian, and Ferdinandotertian, which were hastily given to these common telescopic stars, soon disappeared from the page of science, and even the splendid telescopes of modern times have not been able to add another gem to the diadem of Jupiter.

A modern astronomer of no mean celebrity has, even in the present day, endeavoured to rob Galileo of this staple article of his reputation. From a careless examination of the papers of our celebrated countryman, Thomas Harriot, which Baron Zach had made in 1784, at Petworth, the seat of Lord Egremont, this astronomer has asserted[13] that Harriot first observed the satellites of Jupiter on the 16th of January, 1610; and continued his observations till the 25th of February, 1612. Baron Zach adds the following extraordinary conclusion:—“Galileo pretends to have discovered them on the 7th of January, 1610; so that it is not improbable that Harriot was likewise the first discoverer of these attendants of Jupiter.” In a communication which I received from Dr Robertson, of Oxford, in 1822,[14] he informed me that he had examined a portion of Harriot’s papers, entitled, “De Jovialibus Planetis;” and that it appears, from two pages of these papers, that Harriot first observed Jupiter’s satellites on the 17th of October, 1610. These observations are accompanied with rough drawings of the positions of the satellites, and rough calculations of their periodical revolutions. My friend, Professor Rigaud,[15] who has very recently examined the Harriot MSS., has confirmed the accuracy of Dr Robertson’s observations, and has thus restored to Galileo the honour of being the first and the sole discoverer of these secondary planets.


Galileo announces his discoveries in Enigmas—Discovers the Crescent of Venus—the Ring of Saturn—the Spots on the Sun—Similar Observations made in England by Harriot—Claims of Fabricius and Scheiner to the discovery of the Solar Spots—Galileo’s Letters to Velser on the claims of Scheiner—His residence at the Villa of Salviati—Composes his work on Floating Bodies, which involves him in new controversies.

The great success which attended the first telescopic observations of Galileo, induced him to apply his best instruments to the other planets of our system. The attempts which had been made to deprive him of the honour of some of his discoveries, combined, probably, with a desire to repeat his observations with better telescopes, led him to announce his discoveries under the veil of an enigma, and to invite astronomers to declare, within a given time, if they had observed any new phenomena in the heavens.

Before the close of 1610, Galileo excited the curiosity of astronomers by the publication of his first enigma. Kepler and others tried in vain to decipher it; but in consequence of the Emperor Rodolph requesting a solution of the puzzle, Galileo sent him the following clue:—

In explaining more fully the nature of his observation, Galileo remarked that Saturn was not a single star, but three together, nearly touching one another. He described them as having no relative motion, and as having the form of three o’s, namely, oOo, the central one being larger than those on each side of it.

Although Galileo had announced that nothing new appeared in the other planets, yet he soon communicated to the world another discovery of no slight interest. The enigmatical letters in which it was concealed formed the following sentence:—

Hitherto, Galileo had observed Venus when her disc was largely illuminated; but having directed his telescope to her when she was not far removed from the sun, he saw her in the form of a crescent, resembling exactly the moon at the same elongation. He continued to observe her night after night, during the whole time that she could be seen in the course of her revolution round the sun, and he found that she exhibited the very same phases which resulted from her motion round that luminary.

Galileo had long contemplated a visit to the metropolis of Italy, and he accordingly carried his intentions into effect in the early part of the year 1611. Here he was received with that distinction which was due to his great talents and his extended reputation. Princes, Cardinals, and Prelates hastened to do him honour; and even those who discredited his discoveries, and dreaded their results, vied with the true friends of science in their anxiety to see the intellectual wonder of the age.

In order to show the new celestial phenomena to his friends at Rome, Galileo took with him his best telescope; and as he had discovered the spots on the sun’s surface in October or November 1610, or even earlier,[16] he had the gratification of exhibiting them to his admiring disciples. He accordingly erected his telescope in the Quirinal garden, belonging to Cardinal Bandini; and in April 1611 he shewed them to his friends in many of their most interesting variations. From their change of position on the sun’s disc, Galileo at first inferred, either that the sun revolved about an axis, or that other planets, like Venus and Mercury, revolved so near the sun as to appear like black spots when they were opposite to his disc. Upon continuing his observations, however, he saw reason to abandon this hasty opinion. He found that the spots must be in contact with the surface of the sun,—that their figures were irregular,—that they had different degrees of darkness,—that one spot would often divide itself into three or four,—that three or four spots would often unite themselves into one,—and that all the spots revolved regularly with the sun, which appeared to complete its revolution in about twenty-eight days.

Previous to the invention of the telescope, spots had been more than once seen on the sun’s disc with the unassisted eye. But even if these were of the same character as those which Galileo and others observed, we cannot consider them as anticipations of their discovery by the telescope. As the telescope was now in the possession of several astronomers, Galileo began to have many rivals in discovery; but notwithstanding the claims of Harriot, Fabricius, and Scheiner, it is now placed beyond the reach of doubt that he was the first discoverer of the solar spots. From the communication which I received in 1822 from the late Dr Robertson, of Oxford,[17] it appeared that Thomas Harriot had observed the solar spots on the 8th of December 1610; but his manuscripts, in Lord Egremont’s possession,[18] incontestably prove that his regular observations on the spots did not commence till December 1, 1611, although he had seen the spots at the date above mentioned, and that they were continued till the 18th of January 1613. The observations which he has recorded are 199 in number, and the accounts of them are accompanied with rough drawings representing the number, position, and magnitude of the spots.[19] In the observation of Harriot, made on the 8th December 1610, before he knew of Galileo’s discovery, he saw three spots on the sun, which he has represented in a diagram. The sun was then 7° or 8° high, and there was a frost and a mist, which no doubt acted as a darkening glass. Harriot does not apply the name of spots to what he noticed in this observation, and he does not enumerate it among the 199 observations above mentioned. Professor Rigaud[20] considers it “a misapplication of terms to call such an observation a discovery;” but, with all the respect which we feel for the candour of this remark, we are disposed to confer on Harriot the merit of an original discoverer of the spots on the sun.

Another candidate for the honour of discovering the spots of the sun, was John Fabricius, who undoubtedly saw them previous to June 1611. The dedication of the work[21] in which he has recorded his observation, bears the date of the 13th of June 1611; and it is obvious, from the work itself, that he had seen the spots about the end of the year 1610; but as there is no proof that he saw them before October, we are compelled to assign the priority of the discovery to the Italian astronomer.

The claim of Scheiner, professor of mathematics at Ingolstadt, is more intimately connected with the history of Galileo. This learned astronomer having, early in 1611, turned his telescope to the sun, necessarily discovered the spots which at that time covered his disc. Light flying clouds happened, at the time, to weaken the intensity of his light, so that he was able to show the spots to his pupils. These observations were not published till January 1612; and they appeared in the form of three letters, addressed to Mark Velser, one of the magistrates of Augsburg, under the signature of Appelles post Tabulam. Scheiner, who, many years afterwards, published an elaborate work on the subject, adopted the same idea which had at first occurred to Galileo—that the spots were the dark sides of planets revolving round and near the sun.[22]

On the publication of Scheiner’s letters, Velser transmitted a copy of them to his friend Galileo, with the request that he would favour him with his opinion of the new phenomena. After some delay, Galileo addressed three letters to Velser, in which he combated the opinions of Scheiner on the cause of the spots. The first of these letters was dated the 4th of May 1612;[23] but though the controversy was carried on in the language of mutual respect and esteem, it put an end to the friendship which had existed between the two astronomers. In these letters Galileo showed that the spots often dispersed like vapours or clouds; that they sometimes had a duration of only one or two days, and at other times of thirty or forty days; that they contracted in their breadth when they approached the sun’s limb, without any diminution of their length; that they describe circles parallel to each other; that the monthly rotation of the sun again brings the same spots into view; and that they are seldom seen at a greater distance than 30° from the sun’s equator. Galileo likewise discovered on the sun’s disc faculæ, or luculi, as they were called, which differ in no respect from the common ones but in their being brighter than the rest of the sun’s surface.[24]

In the last of the letters which our author addressed to Velser, and which was written in December 1612, he recurs to his former discovery of the elongated shape, or rather the triple structure, of Saturn. The singular figure which he had observed in this planet had entirely disappeared; and he evidently announces the fact to Velser, lest it should be used by his enemies to discredit the accuracy of his observations. “Looking on Saturn,” says he, “within these few days, I found it solitary, without the assistance of its accustomed stars, and, in short, perfectly round and defined like Jupiter; and such it still remains. Now, what can be said of so strange a metamorphosis? Are the two smaller stars consumed like the spots on the sun? Have they suddenly vanished and fled? or has Saturn devoured his own children? or was the appearance indeed fraud and illusion, with which the glasses have for so long a time mocked me, and so many others who have often observed with me? Now, perhaps, the time is come to revive the withering hopes of those who, guided by more profound contemplations, have followed all the fallacies of the new observations, and recognised their impossibilities. I cannot resolve what to say in a chance so strange, so new, and so unexpected; the shortness of the time, the unexampled occurrence, the weakness of my intellect, and the terror of being mistaken, have greatly confounded me.” Although Galileo struggled to obtain a solution of this mystery, yet he had not the good fortune to succeed. He imagined that the two smaller stars would reappear, in consequence of the supposed revolution of the planet round its axis; but the discovery of the ring of Saturn, and of the obliquity of its plane to the ecliptic, was necessary to explain the phenomena which were so perplexing to our author.

The ill health to which Galileo was occasionally subject, and the belief that the air of Florence was prejudicial to his complaints, induced him to spend much of his time at Selve, the villa of his friend Salviati. This eminent individual had ever been the warmest friend of Galileo, and seems to have delighted in drawing round him the scientific genius of the age. He was a member of the celebrated Lyncæan Society, founded by Prince Frederigo Cesi; and though he is not known as the author of any important discovery, yet he has earned, by his liberality to science, a glorious name, which will be indissolubly united with the immortal destiny of Galileo.

The subject of floating bridges having been discussed at one of the scientific parties which had assembled at the house of Salviati, a difference of opinion arose respecting the influence of the shape of bodies on their disposition to float or to sink in a fluid. Contrary to the general opinion, Galileo undertook to prove that it depended on other causes; and he was thus led to compose his discourse on floating bodies,[25] which was published in 1612, and dedicated to Cosmo de Medici. This work contains many ingenious experiments, and much acute reasoning in support of the true principles of hydrostatics; and it is now chiefly remarkable as a specimen of the sagacity and intellectual power of its author. Like all his other works, it encountered the most violent opposition; and Galileo was more than once summoned into the field to repel the aggressions of his ignorant and presumptuous opponents. The first attack upon it was made by Ptolemy Nozzolini, in a letter to Marzemedici, Archbishop of Florence;[26] and to this Galileo replied in a letter addressed to his antagonist.[27] A more elaborate examination of it was published by Lodovico delle Colombe, and another by M. Vincenzo di Grazia. To these attacks, a minute and overwhelming answer was printed in the name of Benedetti Castelli, the friend and pupil of Galileo; but it was discovered, some years after Galileo’s death, that he was himself the author of this work.[28]


Galileo treats his opponents with severity and sarcasm—He is aided by the sceptics of the day—The Church party the most powerful—Galileo commences the attack, and is answered by Caccini, a Dominican—Galileo’s Letter to the Grand Duchess of Tuscany, in support of the motion of the Earth and the stability of the Sun—- Galileo visits Rome—Is summoned before the Inquisition, and renounces his opinions as heretical—The Inquisition denounces the Copernican System—Galileo has an audience of the Pope, but still maintains his opinions in private society—Proposes to find out the Longitude at Sea by means of Jupiter’s Satellites—His negociation on this subject with the Court of Spain—Its failure—He is unable to observe the three Comets of 1618, but is involved in the controversy to which they gave rise.

The current of Galileo’s life had hitherto flowed in a smooth and unobstructed channel. He had now attained the highest objects of earthly ambition. His discoveries had placed him at the head of the great men of the age; he possessed a professional income far beyond his wants, and even beyond his anticipations; and, what is still dearer to a philosopher, he enjoyed the most perfect leisure for carrying on and completing his discoveries. The opposition which these discoveries encountered, was to him more a subject for triumph than for sorrow. Prejudice and ignorance were his only enemies; and if they succeeded for a while in harassing his march, it was only to lay a foundation for fresh achievements. He who contends for truths which he has himself been permitted to discover, may well sustain the conflict in which presumption and error are destined to fall. The public tribunal may neither be sufficiently pure nor enlightened to decide upon the issue; but he can appeal to posterity, and reckon with confidence on “its sure decree.”

The ardour of Galileo’s mind, the keenness of his temper, his clear perception of truth, and his inextinguishable love of it, combined to exasperate and prolong the hostility of his enemies. When argument failed to enlighten their judgment, and reason to dispel their prejudices, he wielded against them his powerful weapons of ridicule and sarcasm; and in this unrelenting warfare, he seems to have forgotten that Providence had withheld from his enemies those very gifts which he had so liberally received. He who is allowed to take the start of his species, and to penetrate the veil which conceals from common minds the mysteries of nature, must not expect that the world will be patiently dragged at the chariot wheels of his philosophy. Mind has its inertia as well as matter; and its progress to truth can only be insured by the gradual and patient removal of the obstructions which surround it.

The boldness—may we not say the recklessness—with which Galileo insisted upon making proselytes of his enemies, served but to alienate them from the truth. Errors thus assailed speedily entrench themselves in general feelings, and become embalmed in the virulence of the passions. The various classes of his opponents marshalled themselves for their mutual defence. The Aristotelian professors, the temporising Jesuits, the political churchmen, and that timid but respectable body who at all times dread innovation, whether it be in religion or in science, entered into an alliance against the philosophical tyrant who threatened them with the penalties of knowledge.

The party of Galileo, though weak in numbers, was not without power and influence. He had trained around him a devoted band, who idolised his genius and cherished his doctrines. His pupils had been appointed to several of the principal professorships in Italy. The enemies of religion were on this occasion united with the Christian philosopher; and there were, even in these days, many princes and nobles who had felt the inconvenience of ecclesiastical jurisdiction, and who secretly abetted Galileo in his crusade against established errors.

Although these two parties had been long dreading each others power, and reconnoitring each others position, yet we cannot exactly determine which of them hoisted the first signal for war. The church party, particularly its highest dignitaries, were certainly disposed to rest on the defensive. Flanked on one side by the logic of the schools, and on the other by the popular interpretation of Scripture, and backed by the strong arm of the civil power, they were not disposed to interfere with the prosecution of science, however much they may have dreaded its influence. The philosophers, on the contrary, united the zeal of innovators with that firmness of purpose which truth alone can inspire. Victorious in every contest, they were flushed with success, and they panted for a struggle in which they knew they must triumph.

In this state of warlike preparation Galileo addressed a letter, in 1613, to his friend and pupil, the Abbé Castelli, the object of which was to prove that the Scriptures were not intended to teach us science and philosophy. Hence he inferred, that the language employed in the sacred volume in reference to such subjects should be interpreted only in its common acceptation; and that it was in reality as difficult to reconcile the Ptolemaic as the Copernican system to the expressions which occur in the Bible.

A demonstration was about this time made by the opposite party, in the person of Caccini, a Dominican friar, who made a personal attack upon Galileo from the pulpit. This violent ecclesiastic ridiculed the astronomer and his followers, by addressing them sarcastically in the sacred language of Scripture—“Ye men of Galilee, why stand ye here looking up into heaven?” But this species of warfare was disapproved of even by the church; and Luigi Maraffi, the general of the Dominicans, not only apologised to Galileo, who had transmitted to him a formal complaint against Caccini, but expressed the acuteness of his own feelings on being implicated in the “brutal conduct of thirty or forty thousand monks.”

From the character of Caccini, and the part which he afterwards played in the persecution of Galileo, we can scarcely avoid the opinion that his attack from the pulpit was intended as a snare for the unwary philosopher. It roused Galileo from his wonted caution; and stimulated, no doubt, by the nature of the answer which he received from Maraffi, he published a long letter of seventy pages, defending and illustrating his former views respecting the influence of scriptural language on the two contending systems. As if to give the impress of royal authority to this new appeal, he addressed it to Christian, Grand Duchess of Tuscany, the mother of Cosmo; and in this form it seems to have excited a new interest, as if it had expressed the opinion of the grand ducal family. These external circumstances gave additional weight to the powerful and unanswerable reasoning which this letter contains; and it was scarcely possible that any man, possessed of a sound mind, and willing to learn the truth, should refuse his assent to the judicious views of our author. He expresses his belief that the Scriptures were designed to instruct mankind respecting their salvation, and that the faculties of our minds were given us for the purpose of investigating the phenomena of nature. He considers Scripture and nature as proceeding from the same divine author, and, therefore, incapable of speaking a different language; and he points out the absurdity of supposing that professors of astronomy will shut their eyes to the phenomena which they discover in the heavens, or will refuse to believe those deductions of reason which appeal to their judgment with all the power of demonstration. He supports these views by quotations from the ancient fathers; and he refers to the dedication of Copernicus’s own work to the Roman Pontiff, Paul III., as a proof that the Pope himself did not regard the new system of the world as hostile to the sacred writings. Copernicus, on the contrary, tells his Holiness, that the reason of inscribing to him his new system was, that the authority of the Pontiff might put to silence the calumnies of some individuals, who attacked it by arguments drawn from passages of Scripture twisted for their own purpose.

It was in vain to meet such reasoning by any other weapons than those of the civil power. The enemies of Galileo saw that they must either crush the dangerous innovation, or allow it the fullest scope; and they determined upon an appeal to the inquisition. Lorini, a monk of the Dominican order, had already denounced to this body Galileo’s letter to Castelli; and Caccini, bribed by the mastership of the convent of St Mary of Minerva, was invited to settle at Rome for the purpose of embodying the evidence against Galileo.

Though these plans had been carried on in secret, yet Galileo’s suspicions were excited; and he obtained leave from Cosmo to go to Rome about the end of 1615.[29] Here he was lodged in the palace of the Grand Duke’s ambassador, and kept up a constant correspondence with the family of his patron at Florence; but, in the midst of this external splendour, he was summoned before the inquisition to answer for the heretical doctrines which he had published. He was charged with maintaining the motion of the earth, and the stability of the sun—with teaching this doctrine to his pupils—with corresponding on the subject with several German mathematicians—and with having published it, and attempted to reconcile it to Scripture, in his letters to Mark Velser in 1612. The inquisition assembled to consider these charges on the 25th of February 1615; and it was decreed that Galileo should be enjoined by Cardinal Bellarmine to renounce the obnoxious doctrines, and to pledge himself that he would neither teach, defend, nor publish them in future. In the event of his refusing to acquiesce in this sentence, it was decreed that he should be thrown into prison. Galileo did not hesitate to yield to this injunction. On the day following, the 26th of February, he appeared before Cardinal Bellarmine, to renounce his heretical opinions; and, having declared that he abandoned the doctrine of the earth’s motion, and would neither defend nor teach it, in his conversation or in his writings, he was dismissed from the bar of the inquisition.


Having thus disposed of Galileo, the inquisition conceived the design of condemning the whole system of Copernicus as heretical. Galileo, with more hardihood than prudence, remained at Rome for the purpose of giving his assistance in frustrating this plan; but there is reason to think that he injured by his presence the very cause which he meant to support. The inquisitors had determined to put down the new opinions; and they now inserted among the prohibited books Galileo’s letters to Castelli and the Grand Duchess, Kepler’s epitome of the Copernican theory, and Copernicus’s own work on the revolutions of the heavenly bodies.

Notwithstanding these proceedings, Galileo had an audience of the Pope, Paul V., in March 1616. He was received very graciously, and spent nearly an hour with his Holiness. When they were about to part, the Pope assured Galileo, that the congregation were not disposed to receive upon light grounds any calumnies which might be propagated by his enemies, and that, as long as he occupied the papal chair, he might consider himself as safe.

These assurances were no doubt founded on the belief that Galileo would adhere to his pledges; but so bold and inconsiderate was he in the expression of his opinions, that even in Rome he was continually engaged in controversial discussions. The following very interesting account of these disputes is given by Querenghi, in a letter to the Cardinal D’Este:—

“Your eminence would be delighted with Galileo if you heard him holding forth, as he often does, in the midst of fifteen or twenty, all violently attacking him, sometimes in one house, sometimes in another. But he is armed after such fashion that he laughs all of them to scorn; and even if the novelty of his opinions prevents entire persuasion, he at least convicts of emptiness most of the arguments with which his adversaries endeavour to overwhelm him. He was particularly admirable on Monday last in the house of Signor Frederico Ghisilieri; and what especially pleased me was, that before replying to the contrary arguments, he amplified and enforced them with new grounds of great plausibility, so as to leave his adversaries in a more ridiculous plight, when he afterwards overturned them all.”

The discovery of Jupiter’s satellites suggested to Galileo a new method of finding the longitude at sea. Philip III. had encouraged astronomers to direct their attention to this problem, by offering a reward for its solution; and in those days, when new discoveries in science were sometimes rejected as injurious to mankind, it was no common event to see a powerful sovereign courting the assistance of astronomers in promoting the commercial interests of his empire. Galileo seems to have regarded the solution of this problem as an object worthy of his ambition; and he no doubt anticipated the triumph which he would obtain over his enemies, if the Medicean stars, which they had treated with such contempt, could be made subservient to the great interests of mankind. During his residence at Rome in 1615 and 1616, Galileo had communicated his views on this subject to the Comte di Lemos, the Viceroy of Naples, who had presided over the council of the Spanish Indies. This nobleman advised him to apply to the Spanish minister the Duke of Lerma; and, through the influence of the Grand Duke Cosmo, his ambassador at the court of Madrid was engaged to manage the affair. The anxiety of Galileo on this subject was singularly great. He assured the Tuscan ambassador that, in order to accomplish this object, “he was ready to leave all his comforts, his country, his friends, and his family, to cross over into Spain, and to stay as long as he might be wanted at Seville or at Lisbon, or wherever it might be convenient to communicate a knowledge of his method.” The lethargy of the Spanish court seems to have increased with the enthusiasm of Galileo; and though the negotiations were occasionally revived for ten or twelve years, yet no steps were taken to bring them to a close. This strange procrastination has been generally ascribed to jealousy or indifference on the part of Spain; but Nelli, one of Galileo’s biographers, declares, on the authority of Florentine records, that Cosmo had privately requested from the government the privilege of sending annually to the Spanish Indies two Leghorn merchantmen free of duty, as a compensation for the loss of Galileo!

The failure of this negotiation must have been a source of extreme mortification to the high spirit and sanguine temperament of Galileo. He had calculated, however, too securely on his means of putting the new method to a successful trial. The great imperfection of the time-keepers of that day, and the want of proper telescopes, would have baffled him in all his efforts, and he would have been subject to a more serious mortification from the failure and rejection of his plan, than that which he actually experienced from the avarice of his patron, or the indifference of Spain. Even in the present day, no telescope has been invented which is capable of observing at sea the eclipses of Jupiter’s satellites; and though this method of finding the longitude has great advantages on shore, yet it has been completely abandoned at sea, and superseded by easier and more correct methods.

In the year 1618, when no fewer than three comets visited our system, and attracted the attention of all the astronomers of Europe, Galileo was unfortunately confined to his bed by a severe illness; but, though he was unable to make a single observation upon these remarkable bodies, he contrived to involve himself in the controversies which they occasioned. Marco Guiducci, an astronomer of Florence, and a friend of Galileo, had delivered a discourse on comets before the Florentine Academy. The heads of this discourse, which was published in 1619,[30] were supposed to have been communicated to him by Galileo, and this seems to have been universally admitted during the controversy to which it gave rise. The opinion maintained in this treatise, that comets are nothing but meteors which occasionally appear in our atmosphere, like halos and rainbows, savours so little of the sagacity of Galileo that we should be disposed to question its paternity. His inability to partake in the general interest which these three comets excited, and to employ his powerful telescope in observing their phenomena, and their movements, might have had some slight share in the formation of an opinion which deprived them of their importance as celestial bodies. But, however this may have been, the treatise of Guiducci afforded a favourable point of attack to Galileo’s enemies, and the dangerous task was entrusted to Horatio Grassi, a learned Jesuit, who, in a work entitled The Astronomical and Philosophical Balance, criticised the discourse on comets, under the feigned name of Lotario Sarsi.

Galileo replied to this attack in a volume entitled Il Saggiatore, or The Assayer, which, owing to the state of his health, was not published till the autumn of 1623.[31] This work was written in the form of a letter to Virginio Cesarini, a member of the Lyncæan Academy, and master of the chamber to Urban VIII., who had just ascended the papal throne. It was dedicated to the Pontiff himself, and has been long celebrated among literary men for the beauty of its language, though it is doubtless one of the least important of Galileo’s writings.


Urban VIII., Galileo’s friend, raised to the Pontificate—Galileo goes to Rome to offer his congratulations—The Pope loads Galileo with presents, and promises a Pension to his Son—Galileo in pecuniary difficulties, owing to the death of his patron, Cosmo—Galileo again rashly attacks the Church, notwithstanding the Pope’s kindness—He composes his System of the World, to demonstrate the Copernican System—Artfully obtains a license to print it—Nature of the work—Its influence on the public mind—The Pope resolves on suppressing it—Galileo summoned before the Inquisition—His Trial—His Defence—His formal abjuration of his opinions—Observations on his conduct—The Pope shews great indulgence to Galileo, who is allowed to return to his own house at Arcetri, as the place of his confinement.

The succession of the Cardinal Maffeo Barberini to the papal throne, under the name of Urban VIII., was hailed by Galileo and his friends as an event favourable to the promotion of science. Urban had not only been the personal friend of Galileo and of Prince Cesi, the founder of the Lyncæan Academy, but had been intimately connected with that able and liberal association; and it was therefore deemed prudent to secure his favour and attachment. If Paul III. had, nearly a century before, patronised Copernicus, and accepted of the dedication of his great work, it was not unreasonable to expect that, in more enlightened times, another Pontiff might exhibit the same liberality to science.

The plan of securing to Galileo the patronage of Urban VIII. seems to have been devised by Prince Cesi. Although Galileo had not been able for some years to travel, excepting in a litter, yet he was urged by the Prince to perform a journey to Rome, for the express purpose of congratulating his friend upon his elevation to the papal chair. This request was made in October 1623; and though Galileo’s health was not such as to authorise him to undergo so much fatigue, yet he felt the importance of the advice, and, after visiting Cesi at Acqua Sparta, he arrived at Rome in the spring of 1624. The reception which he here experienced far exceeded his most sanguine expectations. During the two months which he spent in the capital he was permitted to have no fewer than six long and gratifying audiences of the Pope. The kindness of his Holiness was of the most marked description. He not only loaded Galileo with presents,[32] and promised him a pension for his son Vincenzo, but he wrote a letter to Ferdinand, who had just succeeded Cosmo as Grand Duke of Tuscany, recommending Galileo to his particular patronage. “For we find in him,” says he, “not only literary distinction, but the love of piety; and he is strong in those qualities by which Pontifical good-will is easily obtained. And now, when he has been brought to this city to congratulate us on our elevation, we have very lovingly embraced him; nor can we suffer him to return to the country whither your liberality recalls him, without an ample provision of Pontifical love. And that you may know how dear he is to us, we have willed to give him this honourable testimonial of virtue and piety. And we further signify, that every benefit which you shall confer upon him, imitating or even surpassing your father’s liberality, will conduce to our gratification.”

Not content with thus securing the friendship of the Pope, Galileo endeavoured to bespeak the good-will of the Cardinals towards the Copernican system. He had, accordingly, many interviews with several of these dignitaries; and he was assured, by Cardinal Hohenzoller, that in a representation which he had made to the Pope on the subject of Copernicus, he stated to his Holiness, “that as all the heretics considered that system as undoubted, it would be necessary to be very circumspect in coming to any resolution on the subject.” To this remark his Holiness replied—“that the church had not condemned this system; and that it should not be condemned as heretical, but only as rash;” and he added, “that there was no fear of any person undertaking to prove that it must necessarily be true.”

The recent appointment of the Abbé Castelli, the friend and pupil of Galileo, to be mathematician to the Pope, was an event of a most gratifying nature; and when we recollect that it was to Castelli that he addressed the famous letter which was pronounced heretical by the Inquisition, we must regard it also as an event indicative of a new and favourable feeling towards the friends of science. The opinions of Urban, indeed, had suffered no change. He was one of the few Cardinals who had opposed the inquisitorial decree of 1616, and his subsequent demeanour was in every respect conformable to the liberality of his early views. The sincerity of his conduct was still further evinced by the grant of a pension of one hundred crowns to Galileo, a few years after his visit to Rome; though there is reason to think that this allowance was not regularly paid.

The death of Cosmo, whose liberality had given him both affluence and leisure, threatened Galileo with pecuniary difficulties. He had been involved in a “great load of debt,” owing to the circumstances of his brother’s family; and, in order to relieve himself, he had requested Castelli to dispose of the pension of his son Vincenzo. In addition to this calamity he was now alarmed at the prospect of losing his salary as an extraordinary professor at Pisa. The great youth of Ferdinand, who was scarcely of age, induced Galileo’s enemies, in 1629, to raise doubts respecting the payment of a salary to a professor who neither resided nor lectured in the university; but the question was decided in his favour, and we have no doubt that the decision was facilitated by the friendly recommendation of the Pope, to which we have already referred.

Although Galileo had made a narrow escape from the grasp of the Inquisition, yet he was never sufficiently sensible of the lenity which he experienced. When he left Rome in 1616, under the solemn pledge of never again teaching the obnoxious doctrine, it was with a hostility against the church, suppressed but deeply cherished; and his resolution to propagate the heresy seems to have been coeval with the vow by which he renounced it. In the year 1618, when he communicated his theory of the tides to the Archduke Leopold, he alludes in the most sarcastic manner to the conduct of the church. The same hostile tone, more or less, pervaded all his writings, and, while he laboured to sharpen the edge of his satire, he endeavoured to guard himself against its effects, by an affectation of the humblest deference to the decisions of theology. Had Galileo stood alone, his devotion to science might have withdrawn him from so hopeless a contest; but he was spurred on by the violence of a party. The Lyncæan Academy never scrupled to summon him from his researches. They placed him in the forlorn hope of their combat, and he at last fell a victim to the rashness of his friends.

But whatever allowance we may make for the ardour of Galileo’s temper, and the peculiarity of his position; and however we may justify and even approve of his past conduct, his visit to Urban VIII., in 1624, placed him in a new relation to the church, which demanded on his part a new and corresponding demeanour. The noble and generous reception which he met with from Urban, and the liberal declaration of Cardinal Hohenzoller on the subject of the Copernican system, should have been regarded as expressions of regret for the past, and offers of conciliation for the future. Thus honoured by the head of the church, and befriended by its dignitaries, Galileo must have felt himself secure against the indignities of its lesser functionaries, and in the possession of the fullest license to prosecute his researches and publish his discoveries, provided he avoided that dogma of the church which, even in the present day, it has not ventured to renounce. But Galileo was bound to the Romish hierarchy by even stronger ties. His son and himself were pensioners of the church, and, having accepted of its alms, they owed to it, at least, a decent and respectful allegiance. The pension thus given by Urban was not a remuneration which sovereigns sometimes award to the services of their subjects. Galileo was a foreigner at Rome. The sovereign of the papal state owed him no obligation; and hence we must regard the pension of Galileo as a donation from the Roman Pontiff to science itself, and as a declaration to the Christian world that religion was not jealous of philosophy, and that the church of Rome was willing to respect and foster even the genius of its enemies.

Galileo viewed all these circumstances in a different light. He resolved to compose a work in which the Copernican system should be demonstrated; but he had not the courage to do this in a direct and open manner. He adopted the plan of discussing the subject in a dialogue between three speakers, in the hope of eluding by this artifice the censure of the church. This work was completed in 1630, but, owing to some difficulties in obtaining a license to print it, it was not published till 1632.

In obtaining this license, Galileo exhibited considerable address, and his memory has not escaped from the imputation of having acted unfairly, and of having involved his personal friends in the consequences of his imprudence.

The situation of master of the palace was, fortunately for Galileo’s designs, filled by Nicolo Riccardi, a friend and pupil of his own. This officer was a sort of censor of new publications, and when he was applied to on the subject of printing his work, Galileo soon found that attempts had previously been made to thwart his views. He instantly set off for Rome, and had an interview with his friend, who was in every respect anxious to oblige him. Riccardi examined the manuscript, pointed out some incautious expressions which he considered it necessary to erase, and returned it with his written approbation, on the understanding that the alterations he suggested would be made. Dreading to remain in Rome during the unhealthy season, which was fast approaching, Galileo returned to Florence, with the intention of completing the index and dedication, and of sending the MS. to Rome, to be printed under the care of Prince Cesi. The death of that distinguished individual, in August 1630, frustrated Galileo’s plan, and he applied for leave to have the book printed in Florence. Riccardi was at first desirous to examine the MS. again, but, after inspecting only the beginning and the end of it, he gave Galileo leave to print it wherever he chose, providing it bore the license of the Inquisitor-General of Florence, and one or two other persons whom he named.

Having overcome all these difficulties, Galileo’s work was published in 1632, under the title of “The System of the World of Galileo Galilei, &c., in which, in four dialogues concerning the two principal systems of the world—the Ptolemaic and the Copernican—he discusses, indeterminately and firmly, the arguments proposed on both sides.” It is dedicated to Ferdinand, Grand Duke of Tuscany, and is prefaced by an “Address to the prudent reader,” which is itself characterised by the utmost imprudence. He refers to the decree of the Inquisition in the most insulting and ironical language. He attributes it to passion and to ignorance, not by direct assertion, but by insinuations ascribed to others; and he announces his intention to defend the Copernican system, as a pure mathematical hypothesis, and not as an opinion having an advantage over that of the stability of the earth absolutely. The dialogue is conducted by three persons, Salviati, Sagredo, and Simplicio. Salviati, who is the true philosopher in the dialogue, was the real name of a nobleman whom we have already had occasion to mention. Sagredo, the name of another noble friend of Galileo’s, performs a secondary part under Salviati. He proposes doubts, suggests difficulties, and enlivens the gravity of the dialogue with his wit and pleasantry. Simplicio is a resolute follower of Ptolemy and Aristotle, and, with a proper degree of candour and modesty, he brings forward all the common arguments in favour of the Ptolemaic system. Between the wit of Sagredo, and the powerful philosophy of Salviati, the peripatetic sage is baffled in every discussion; and there can be no doubt that Galileo aimed a more fatal blow at the Ptolemaic system by this mode of discussing it, than if he had endeavoured to overturn it by direct arguments.

The influence of this work on the public mind was such as might have been anticipated. The obnoxious doctrines which it upheld were eagerly received, and widely disseminated; and the church of Rome became sensible of the shock which was thus given to its intellectual supremacy. Pope Urban VIII., attached though he had been to Galileo, never once hesitated respecting the line of conduct which he felt himself bound to pursue. His mind was, nevertheless, agitated with conflicting sentiments. He entertained a sincere affection for science and literature, and yet he was placed in the position of their enemy. He had been the personal friend of Galileo, and yet his duty compelled him to become his accuser. Embarrassing as these feelings were, other considerations contributed to soothe him. He had, in his capacity of a Cardinal, opposed the first persecution of Galileo. He had, since his elevation to the pontificate, traced an open path for the march of Galileo’s discoveries; and he had finally endeavoured to bind the recusant philosopher by the chains of kindness and gratitude. All these means, however, had proved abortive, and he was now called upon to support the doctrine which he had subscribed, and administer the law of which he was the guardian.

It has been supposed, without any satisfactory evidence, that Urban may have been influenced by less creditable motives. Salviati and Sagredo being well-known personages, it was inferred that Simplicio must also have a representative. The enemies of Galileo are said to have convinced his Holiness that Simplicio was intended as a portraiture of himself; and this opinion received some probability from the fact, that the peripatetic disputant had employed many of the arguments which Urban had himself used in his discussions with Galileo. The latest biographer of Galileo[33] regards this motive as necessary to account for “the otherwise inexplicable change which took place in the conduct of Urban to his old friend;”—but we cannot admit the truth of this supposition. The church had been placed in hostility to a powerful and liberal party, which was adverse to its interests. The dogmas of the Catholic faith had been brought into direct collision with the deductions of science. The leader of the philosophic band had broken the most solemn armistice with the Inquisition: he had renounced the ties of gratitude which bound him to the Pontiff; and Urban was thus compelled to entrench himself in a position to which he had been driven by his opponents.

The design of summoning Galileo before the Inquisition, seems to have been formed almost immediately after the publication of his book; for even in August 1632, the preliminary proceedings had reached the ears of the Grand Duke Ferdinand. The Tuscan ambassador at Rome was speedily acquainted with the dissatisfaction which his Sovereign felt at these proceedings; and he was instructed to forward to Florence a written statement of the charges against Galileo, in order to enable him to prepare for his defence. Although this request was denied, Ferdinand again interposed, and transmitted a letter to his ambassador, recommending the admission of Campanella and Castelli into the congregation of ecclesiastics by whom Galileo was to be judged. Circumstances, however, rendered it prudent to withhold this letter. Castelli was sent away from Rome, and Scipio Chiaramonte, a bigotted ecclesiastic, was summoned from Pisa to complete the number of the judges.

It appears from a despatch of the Tuscan minister, that Ferdinand was enraged at the transaction; and he instructed his ambassador, Niccolini, to make the strongest representations to the Pope. Niccolini had several interviews with his Holiness; but all his expostulations were fruitless. He found Urban highly incensed against Galileo; and his Holiness begged Niccolini to advise the Archduke not to interfere any farther, as he would not “get through it with honour.” On the 15th of September the Pope caused it to be intimated to Niccolini, as a mark of his especial esteem for the Grand Duke, that he was obliged to refer the work to the Inquisition; but both the prince and his ambassador were declared liable to the usual censures if they divulged the secret.

From the measures which this tribunal had formerly pursued, it was not difficult to foresee the result of their present deliberations. They summoned Galileo to appear before them at Rome, to answer in person the charges under which he lay. The Tuscan ambassador expostulated warmly with the court of Rome on the inhumanity of this proceeding. He urged his advanced age, his infirm health, the discomforts of the journey, and the miseries of the quarantine,[34] as motives for reconsidering their decision: But the Pope was inexorable, and though it was agreed to relax the quarantine as much as possible in his favour, yet it was declared indispensable that he should appear in person before the Inquisition.

Worn out with age and infirmities, and exhausted with the fatigues of his journey, Galileo arrived at Rome on the 14th of February, 1633. The Tuscan ambassador announced his arrival in an official form to the commissary of the holy office, and Galileo awaited in calm dignity the approach of his trial. Among those who proffered their advice in this distressing emergency, we must enumerate the Cardinal Barberino, the Pope’s nephew, who, though he may have felt the necessity of an interference on the part of the church, was yet desirous that it should be effected with the least injury to Galileo and to science. He accordingly visited Galileo, and advised him to remain as much at home as possible, to keep aloof from general society, and to see only his most intimate friends. The same advice was given from different quarters; and Galileo, feeling its propriety, remained in strict seclusion in the palace of the Tuscan ambassador.

During the whole of the trial which had now commenced, Galileo was treated with the most marked indulgence. Abhorring, as we must do, the principles and practice of this odious tribunal, and reprobating its interference with the cautious deductions of science, we must yet admit that, on this occasion, its deliberations were not dictated by passion, nor its power directed by vengeance. Though placed at their judgment-seat as a heretic, Galileo stood there with the recognised attributes of a sage; and though an offender against the laws of which they were the guardian, yet the highest respect was yielded to his genius, and the kindest commiseration to his infirmities.

In the beginning of April, when his examination in person was to commence, it became necessary that he should be removed to the holy office; but instead of committing him, as was the practice, to solitary confinement, he was provided with apartments in the house of the fiscal of the Inquisition. His table was provided by the Tuscan ambassador, and his servant was allowed to attend him at his pleasure, and to sleep in an adjoining apartment. Even this nominal confinement, however, Galileo’s high spirit was unable to brook. An attack of the disease to which he was constitutionally subject contributed to fret and irritate him, and he became impatient for a release from his anxiety as well as from his bondage. Cardinal Barberino seems to have received notice of the state of Galileo’s feelings, and, with a magnanimity which posterity will ever honour, he liberated the philosopher on his own responsibility; and in ten days after his first examination, and on the last day of April, he was restored to the hospitable roof of the Tuscan ambassador.

Though this favour was granted on the condition of his remaining in strict seclusion, Galileo recovered his health, and to a certain degree his usual hilarity, amid the kind attentions of Niccolini and his family; and when the want of exercise had begun to produce symptoms of indisposition, the Tuscan minister obtained for him leave to go into the public gardens in a half-closed carriage.

After the Inquisition had examined Galileo personally, they allowed him a reasonable time for preparing his defence. He felt the difficulty of adducing any thing like a plausible justification of his conduct; and he resorted to an ingenious, though a shallow artifice, which was regarded by the court as an aggravation of the crime. After his first appearance before the Inquisition in 1616, he was publicly and falsely charged by his enemies with having then abjured his opinions; and he was taunted as a criminal who had been actually punished for his offences. As a refutation of these calumnies, Cardinal Bellarmine had given him a certificate in his own handwriting, declaring that he neither abjured his opinions, nor suffered punishment for them; and that the doctrine of the earth’s motion, and the sun’s stability, was only denounced to him as contrary to Scripture, and as one which could not be defended. To this certificate the Cardinal did not add, because he was not called upon to do it, that Galileo was enjoined not to teach in any manner the doctrine thus denounced; and Galileo ingeniously avails himself of this supposed omission, to account for his having, in the lapse of fourteen or sixteen years, forgotten the injunction. He assigned the same excuse for his having omitted to mention this injunction to Riccardi, and to the Inquisitor-General at Florence, when he obtained the licence to print his Dialogues. The court held the production of this certificate to be at once a proof and an aggravation of his offence, because the certificate itself declared that the obnoxious doctrines had been pronounced contrary to the Holy Scriptures.

Having duly weighed the confessions and excuses of their prisoner, and considered the general merits of the case, the Inquisition came to an agreement upon the sentence which they were to pronounce, and appointed the 22d of June as the day on which it was to be delivered. Two days previous to this, Galileo was summoned to appear at the holy office; and on the morning of the 21st, he obeyed the summons. On the 22d of June he was clothed in a penitential dress, and conducted to the convent of Minerva, where the Inquisition was assembled to give judgment. A long and elaborate sentence was pronounced, detailing the former proceedings of the Inquisition, and specifying the offences which he had committed in teaching heretical doctrines, in violating his former pledges, and in obtaining by improper means a license for the printing of his Dialogues. After an invocation of the name of our Saviour, and of the Holy Virgin, Galileo is declared to have brought himself under strong suspicions of heresy, and to have incurred all the censures and penalties which are enjoined against delinquents of this kind; but from all these consequences he is to be held absolved, provided that with a sincere heart, and a faith unfeigned, he abjures and curses the heresies he has cherished, as well as every other heresy against the Catholic church. In order that his offence might not go altogether unpunished, that he might be more cautious in future, and be a warning to others to abstain from similar delinquencies, it was also decreed that his Dialogues should be prohibited by public edict; that he himself should be condemned to the prison of the Inquisition during their pleasure, and that, in the course of the next three years, he should recite once a week the seven penitential psalms.

The ceremony of Galileo’s abjuration was one of exciting interest, and of awful formality. Clothed in the sackcloth of a repentant criminal, the venerable sage fell upon his knees before the assembled Cardinals; and laying his hands upon the Holy Evangelists, he invoked the Divine aid in abjuring and detesting, and vowing never again to teach, the doctrine of the earth’s motion, and of the sun’s stability. He pledged himself that he would never again, either in words or in writing, propagate such heresies; and he swore that he would fulfil and observe the penances which had been inflicted upon him.[35] At the conclusion of this ceremony, in which he recited his abjuration word for word, and then signed it, he was conveyed, in conformity with his sentence, to the prison of the Inquisition.

The account which we have now given of the trial and the sentence of Galileo, is pregnant with the deepest interest and instruction. Human nature is here drawn in its darkest colouring; and in surveying the melancholy picture, it is difficult to decide whether religion or philosophy has been most degraded. While we witness the presumptuous priest pronouncing infallible the decrees of his own erring judgment, we see the high-minded philosopher abjuring the eternal and immutable truths which he had himself the glory of establishing. In the ignorance and prejudices of the age—in a too literal interpretation of the language of Scripture—in a mistaken respect for the errors that had become venerable from their antiquity—and in the peculiar position which Galileo had taken among the avowed enemies of the church, we may find the elements of an apology, poor though it be, for the conduct of the Inquisition. But what excuse can we devise for the humiliating confession and abjuration of Galileo? Why did this master-spirit of the age—this high-priest of the stars—this representative of science—this hoary sage, whose career of glory was near its consummation—why did he reject the crown of martyrdom which he had himself coveted, and which, plaited with immortal laurels, was about to descend upon his head? If, in place of disavowing the laws of Nature, and surrendering in his own person the intellectual dignity of his species, he had boldly asserted the truth of his opinions, and confided his character to posterity, and his cause to an all-ruling Providence, he would have strung up the hair-suspended sabre, and disarmed for ever the hostility which threatened to overwhelm him. The philosopher, however, was supported only by philosophy; and in the love of truth he found a miserable substitute for the hopes of the martyr. Galileo cowered under the fear of man, and his submission was the salvation of the church. The sword of the Inquisition descended on his prostrate neck; and though its stroke was not physical, yet it fell with a moral influence fatal to the character of its victim, and to the dignity of science.

In studying with attention this portion of scientific history, the reader will not fail to perceive that the Church of Rome was driven into a dilemma, from which the submission and abjuration of Galileo could alone extricate it. He who confesses a crime and denounces its atrocity, not only sanctions but inflicts the punishment which is annexed to it. Had Galileo declared his innocence, and avowed his sentiments, and had he appealed to the past conduct of the Church itself, to the acknowledged opinions of its dignitaries, and even to the acts of its pontiffs, he would have at once confounded his accusers, and escaped from their toils. After Copernicus, himself a catholic priest, had openly maintained the motion of the earth, and the stability of the sun:—after he had dedicated the work which advocated these opinions to Pope Paul III., on the express ground that the authority of the pontiff might silence the calumnies of those who attacked these opinions by arguments drawn from Scripture:—after the Cardinal Schonberg and the Bishop of Culm had urged Copernicus to publish the new doctrines;—and after the Bishop of Ermeland had erected a monument to commemorate his great discoveries;—how could the Church of Rome have appealed to its pontifical decrees as the ground of persecuting and punishing Galileo? Even in later times, the same doctrines had been propagated with entire toleration: Nay, in the very year of Galileo’s first persecution, Paul Anthony Foscarinus, a learned Carmelite monk, wrote a pamphlet, in which he illustrates and defends the mobility of the earth, and endeavours to reconcile to this new doctrine the passages of Scripture which had been employed to subvert it. This very singular production was dated from the Carmelite convent at Naples; was dedicated to the very reverend Sebastian Fantoni, general of the Carmelite order; and, sanctioned by the ecclesiastical authorities, it was published at Naples in 1615, the very year of the first persecution of Galileo.

Nor was this the only defence of the Copernican system which issued from the bosom of the Church. Thomas Campanella, a Calabrian monk, published, in 1622, “An Apology for Galileo,” and he even dedicates it to D. Boniface, Cardinal of Cajeta. Nay, it appears from the dedication, that he undertook the work at the command of the Cardinal, and that the examination of the question had been entrusted to the Cardinal by the Holy Senate. After an able defence of his friend, Campanella refers, at the conclusion of his apology, to the suppression of Galileo’s writings, and justly observes, that the effect of such a measure would be to make them more generally read, and more highly esteemed. The boldness of the apologist, however, is wisely tempered with the humility of the ecclesiastic, and he concludes his work with the declaration, that in all his opinions, whether written or to be written, he submits himself to the opinions of the Holy Mother Church of Rome and to the judgment of his superiors.

By these proceedings of the dignitaries, as well as the clergy of the Church of Rome, which had been tolerated for more than a century, the decrees of the pontiffs against the doctrine of the earth’s motion were virtually repealed; and Galileo might have pleaded them with success in arrest of judgment. Unfortunately, however, for himself and for science, he acted otherwise. By admitting their authority, he revived in fresh force these obsolete and obnoxious enactments; and, by yielding to their power, he riveted for another century the almost broken chains of spiritual despotism.

It is a curious fact in the annals of heresy and sedition, that opinions maintained with impunity by one individual, have, in the same age, brought others to the stake or to the scaffold. The results of deep research or extravagant speculation seldom provoke hostility, when meekly announced as the deductions of reason or the convictions of conscience. As the dreams of a recluse or of an enthusiast, they may excite pity or call forth contempt; but, like seed quietly cast into the earth, they will rot and germinate according to the vitality with which they are endowed. But, if new and startling opinions are thrown in the face of the community—if they are uttered in triumph or in insult—in contempt of public opinion, or in derision of cherished errors, they lose the comeliness of truth in the rancour of their propagation; and they are like seed scattered in a hurricane, which only irritates and blinds the husbandman. Had Galileo concluded his System of the World with the quiet peroration of his apologist Campanella, and dedicated it to the Pope, it might have stood in the library of the Vatican, beside the cherished though equally heretical volume of Copernicus.

In the abjuration of his opinions by Galileo, Pope Urban VII. did not fail to observe the full extent of his triumph; and he exhibited the utmost sagacity in the means which he employed to secure it. While he endeavoured to overawe the enemies of the church by the formal promulgation of Galileo’s sentence and abjuration, and by punishing the officials who had assisted in obtaining the license to print his work, he treated Galileo with the utmost lenity, and yielded to every request that was made to diminish, and almost suspend, the constraint under which he lay. The sentence of abjuration was ordered to be publicly read at several universities. At Florence the ceremonial was performed in the church of Santa Croce, and the friends and disciples of Galileo were especially summoned to witness the public degradation of their master. The inquisitor at Florence was ordered to be reprimanded for his conduct; and Riccardi, the master of the sacred palace, and Ciampoli, the secretary of Pope Urban himself, were dismissed from their situations.

Galileo had remained only four days in the prison of the Inquisition, when, on the application of Niccolini, the Tuscan ambassador, he was allowed to reside with him in his palace. As Florence still suffered under the contagious disease which we have already mentioned, it was proposed that Sienna should be the place of Galileo’s confinement, and that his residence should be in one of the convents of that city. Niccolini, however, recommended the palace of the Archbishop Piccolomoni as a more suitable residence; and though the Archbishop was one of Galileo’s best friends, the Pope agreed to the arrangement, and in the beginning of July Galileo quitted Rome for Sienna.

After having spent nearly six months under the hospitable roof of his friend, with no other restraint than that of being confined to the limits of the palace, Galileo was permitted to return to his villa near Florence under the same restrictions; and as the contagious disease had disappeared in Tuscany, he was able in the month of December to re-enter his own house at Arcetri, where he spent the remainder of his days.


Galileo loses his favourite Daughter—He falls into a state of melancholy and ill health—Is allowed to go to Florence for its recovery in 1638—But is prevented from leaving his House or receiving his Friends—His friend Castelli permitted to visit him in the presence of an Officer of the Inquisition—He composes his celebrated Dialogues on Local Motion—Discovers the Moon’s Libration—Loses the sight of one Eye—The other Eye attacked by the same Disease—Is struck blind—Negociates with the Dutch Government respecting his Method of finding the Longitude—He is allowed free intercourse with his Friends—His Illness and Death in 1642—His Epitaph—His Social, Moral, and Scientific Character.

Although Galileo had now the happiness of rejoining his family under their paternal roof, yet, like all sublunary blessings, it was but of short duration. His favourite daughter Maria, who along with her sister had joined the convent of St Matthew in the neighbourhood of Arcetri, had looked forward to the arrival of her father with the most affectionate anticipations. She hoped that her filial devotion might form some compensation for the malignity of his enemies, and she eagerly assumed the labour of reciting weekly the seven penitentiary psalms which formed part of her father’s sentence. These sacred duties, however, were destined to terminate almost at the moment they were begun. She was seized with a fatal illness in the same month in which she rejoined her parent, and before the month of April she was no more. This heavy blow, so suddenly struck, overwhelmed Galileo in the deepest agony. Owing to the decline of his health, and the recurrence of his old complaints, he was unable to oppose to this mental suffering the constitutional energy of his mind. The bulwarks of his heart broke down, and a flood of grief desolated his manly and powerful mind. He felt, as he expressed it, that he was incessantly called by his daughter—his pulse intermitted—his heart was agitated with unceasing palpitations—his appetite entirely left him, and he considered his dissolution so near at hand, that he would not permit his son Vicenzo to set out upon a journey which he had contemplated.

From this state of melancholy and indisposition, Galileo slowly, though partially, recovered, and, with the view of obtaining medical assistance, he requested leave to go to Florence. His enemies, however, refused this application, and he was given to understand that any additional importunities would be visited with a more vigilant surveillance. He remained, therefore, five years at Arcetri, from 1634 to 1638, without any remission of his confinement, and pursuing his studies under the influence of a continued and general indisposition.

There is no reason to think that Galileo or his friends renewed their application to the Church of Rome; but, in 1638, the Pope transmitted, through the Inquisitor Fariano, his permission that he might remove to Florence for the recovery of his health, on the condition that he should present himself at the office of the Inquisitor to learn the terms upon which this indulgence was granted. Galileo accepted of the kindness thus unexpectedly proffered. But the conditions upon which it was given were more severe than he expected. He was prohibited from leaving his house or admitting his friends; and so sternly was this system pursued, that he required a special order for attending mass during passion week.

The severity of this order was keenly felt by Galileo. While he remained at Arcetri, his seclusion from the world would have been an object of choice, if it had not been the decree of a tribunal; but to be debarred from the conversation of his friends in Florence—in that city where his genius had been idolised, and where his fame had become immortal, was an aggravation of punishment which he was unable to bear. With his accustomed kindness, the Grand Duke made a strong representation on the subject to his ambassador at the Court of Rome. He stated that, from his great age and infirmities, Galileo’s career was near its close; that he possessed many valuable ideas, which the world might lose if they were not matured and conveyed to his friends; and that Galileo was anxious to make these communications to Father Castelli, who was then a stipendiary of the Court of Rome. The Grand Duke commanded his ambassador to see Castelli on the subject—to urge him to obtain leave from the Pope to spend a few months in Florence—and to supply him with money and every thing that was necessary for his journey. Influenced by this kind and liberal message, Castelli obtained an audience of the Pope, and requested leave to pay a visit to Florence. Urban instantly suspected the object of his journey; and, upon Castelli’s acknowledging that he could not possibly refrain from seeing Galileo, he received permission to visit him in the company of an officer of the Inquisition. Castelli accordingly went to Florence, and, a few months afterwards, Galileo was ordered to return to Arcetri.

During Galileo’s confinement at Sienna and Arcetri, between 1633 and 1638, his time was principally occupied in the composition of his “Dialogues on Local Motion,” in which he treats of the strength and cohesion of solid bodies, of the laws of uniform and accelerated motions, of the motion of projectiles, and of the centre of gravity of solids. This remarkable work, which was considered by its author as the best of his productions, was printed by Louis Elzevir, at Amsterdam, and dedicated to the Count de Noailles, the French ambassador at Rome. Various attempts to have it printed in Germany had failed; and, in order to save himself from the malignity of his enemies, he was obliged to pretend that the edition published in Holland had been printed from a MS. entrusted to the French ambassador.

Although Galileo had for a long time abandoned his astronomical studies, yet his attention was directed, about the year 1636, to a curious appearance in the lunar disc, which is known by the name of the moon’s libration. When we examine with a telescope the outline of the moon, we observe that certain parts of her disc, which are seen at one time, are invisible at another. This change or libration is of four different kinds, viz. the diurnal libration, the libration in longitude, the libration in latitude, and the spheroidal libration. Galileo discovered the first of these kinds of libration, and appears to have had some knowledge of the second; but the third was discovered by Hevelius, and the fourth by Lagrange.

This curious discovery was the result of the last telescopic observations of Galileo. Although his right eye had for some years lost its power, yet his general vision was sufficiently perfect to enable him to carry on his usual researches. In 1636, however, this affection of his eye became more serious; and, in 1637, his left eye was attacked with the same disease. His medical friends at first supposed that cataracts were formed in the crystalline lens, and anticipated a cure from the operation of couching. These hopes were fallacious. The disease turned out to be in the cornea, and every attempt to restore its transparency was fruitless. In a few months the white cloud covered the whole aperture of the pupil, and Galileo became totally blind. This sudden and unexpected calamity had almost overwhelmed Galileo and his friends. In writing to a correspondent he exclaims, “Alas! your dear friend and servant has become totally and irreparably blind. These heavens, this earth, this universe, which by wonderful observation I had enlarged a thousand times beyond the belief of past ages, are henceforth shrunk into the narrow space which I myself occupy. So it pleases God; it shall, therefore, please me also.” His friend, Father Castelli, deplores the calamity in the same tone of pathetic sublimity:—“The noblest eye,” says he, “which nature ever made, is darkened; an eye so privileged, and gifted with such rare powers, that it may truly be said to have seen more than the eyes of all that are gone, and to have opened the eyes of all that are to come.”

Although Galileo had been thwarted in his attempt to introduce into the Spanish marine his new method of finding the longitude at sea, yet he never lost sight of an object to which he attached the highest importance. As the formation of correct tables of the motion of Jupiter’s satellites was a necessary preliminary to its introduction, he had occupied himself for twenty-four years in observations for this purpose, and he had made considerable progress in this laborious task. After the publication of his “Dialogues on Motion,” in 1636, he renewed his attempts to bring his method into actual use. For this purpose he addressed himself to Lorenzo Real, who had been the Dutch Governor-General in India, and offered the free use of his method to the States-General of Holland.[36] The Dutch government received this proposal with an anxious desire to have it carried into effect. At the instigation of Constantine Huygens, the father of the illustrious Huygens, and the secretary to the Prince of Orange, they appointed commissioners to communicate with Galileo; and while they transmitted him a gold chain as a mark of their esteem, they at the same time assured him, that if his plan should prove successful it should not pass unrewarded. The commissioners entered into an active correspondence with Galileo, and had even appointed one of their number to communicate personally with him in Italy. Lest this, however, should excite the jealousy of the court of Rome, Galileo objected to the arrangement, so that the negociation was carried on solely by correspondence.

It was at this time that Galileo was struck with blindness. His friend and pupil, Renieri, undertook in this emergency to arrange and complete his observations and calculations; but before he had made much progress in the arduous task, each of the four commissioners died in succession, and it was with great difficulty that Constantine Huygens succeeded in renewing the scheme. It was again obstructed, however, by the death of Galileo; and when Renieri was about to publish, by the order of the Grand Duke, the “Ephemeris,” and “Tables of the Jovian Planets,” he was attacked with a mortal disease, and the manuscripts of Galileo, which he was on the eve of publishing, were never more heard of. By such a series of misfortunes were the plans of Galileo and of the States-General completely overthrown. It is some consolation, however, to know that neither science nor navigation suffered any severe loss. Notwithstanding the perfection of our present tables of Jupiter’s satellites, and of the astronomical instruments by which their eclipses may be observed, the method of Galileo is still impracticable at sea.

In consequence of the strict seclusion to which Galileo had been subjected, he was in the practice of dating his letters from his prison at Arcetri; but after he had lost the use of his eyes, the Inquisition seems to have relaxed its severity, and to have allowed him the freest intercourse with his friends. The Grand Duke of Tuscany paid him frequent visits; and among the celebrated strangers who came from distant lands to see the ornament of Italy, were Gassendi, Deodati, and our illustrious countryman Milton. During the last three years of his life, his eminent pupil Viviani formed one of his family; and in October 1641, the celebrated Torricelli, another of his pupils, was admitted to the same distinction.

Though the powerful mind of Galileo still retained its vigour, yet his debilitated frame was exhausted with mental labour. He often complained that his head was too busy for his body; and the continuity of his studies was frequently broken with attacks of hypochondria, want of sleep, and acute rheumatic pains. Along with these calamities, he was afflicted with another still more severe—with deafness almost total; but though he was now excluded from all communication with the external world, yet his mind still grappled with the material universe, and while he was studying the force of percussion, and preparing for a continuation of his “Dialogues on Motion,” he was attacked with fever and palpitation of the heart, which, after continuing two months, terminated fatally on the 8th of January 1642, in the 78th year of his age.

Having died in the character of a prisoner of the Inquisition, this odious tribunal disputed his right of making a will, and of being buried in consecrated ground. These objections, however, were withdrawn; but though a large sum was subscribed for erecting a monument to him in the church of Santa Croce, in Florence, the Pope would not permit the design to be carried into execution. His sacred remains were, therefore, deposited in an obscure corner of the church, and remained for more than thirty years unmarked with any monumental tablet. The following epitaph, given without any remark in the Leyden edition of his Dialogues, is, we presume, the one which was inscribed on a tablet in the church of Santa Croce:—

Florentino, Philosopho et Geometræ vere lynceo, Naturæ Œdipo, Mirabilium semper inventorum machinatori, Qui inconcessa adhuc mortalibus gloria Cælorum provincias auxit Et universo dedit incrementum: Non enim vitreos spherarum orbes Fragilesque stellas conflavit: Sed æterna mundi corpore Mediceæ beneficentiæ dedicavit, Cujus inextincta gloriæ cupiditas Ut oculos nationum Sæculorumque omnium Videre doceret, Proprios impendit oculos. Cum jam nil amplius haberet natura Quod ipse videret. Cujus inventa vix intra rerum limites comprehensa Firmamentum ipsum non solum continet, Sed etiam recipit. Qui relictis tot scientiarum monumentis Plura secum tulit, quam reliquit. Gravi enim Sed nondum affecta senectute, Novis contemplationibus Majorem gloriam affectans Inexplebilem sapientiæ animam Immaturo nobis obitu Exhalavit Anno Domini . Ætatis suæ .

At his death, in 1703, Viviani purchased his property, with the charge of erecting a monument over Galileo’s remains and his own. This design was not carried into effect till 1737, at the expense of the family of Nelli, when both their bodies were disinterred, and removed to the site of the splendid monument which now covers them. This monument contains the bust of Galileo, with figures of Geometry and Astronomy. It was designed by Giulio Foggini. Galileo’s bust was executed by Giovanni Battista Foggini; the figure of Astronomy by Vincenzio Foggini, his son; and that of Geometry by Girolamo Ticciati.

Galileo’s house at Arcetri still remains. In 1821 it belonged to one Signor Alimari, having been preserved in the state in which it was left by Galileo; it stands very near the convent of St Matthew, and about a mile to the S. E. of Florence. An inscription by Nelli, over the door of the house, still remains.

The character of Galileo, whether we view him as a member of the social circle, or as a man of science, presents many interesting and instructive points of contemplation. Unfortunate, and to a certain extent immoral, in his domestic relations, he did not derive from that hallowed source all the enjoyments which it generally yields; and it was owing to this cause, perhaps, that he was more fond of society than might have been expected from his studious habits. His habitual cheerfulness and gaiety, and his affability and frankness of manner, rendered him an universal favourite among his friends. Without any of the pedantry of exclusive talent, and without any of that ostentation which often marks the man of limited though profound acquirements, Galileo never conversed upon scientific or philosophical subjects except among those who were capable of understanding them. The extent of his general information, indeed, his great literary knowledge, but, above all, his retentive memory, stored with the legends and the poetry of ancient times, saved him from the necessity of drawing upon his own peculiar studies for the topics of his conversation.

Galileo was not less distinguished for his hospitality and benevolence; he was liberal to the poor, and generous in the aid which he administered to men of genius and talent, who often found a comfortable asylum under his roof. In his domestic economy he was frugal without being parsimonious. His hospitable board was ever ready for the reception of his friends; and, though he was himself abstemious in his diet, he seems to have been a lover of good wines, of which he received always the choicest varieties out of the Grand Duke’s cellar. This peculiar taste, together with his attachment to a country life, rendered him fond of agricultural pursuits, and induced him to devote his leisure hours to the cultivation of his vineyards.

In his personal appearance Galileo was about the middle size, and of a square-built, but well-proportioned, frame. His complexion was fair, his eyes penetrating, and his hair of a reddish hue. His expression was cheerful and animated, and though his temper was easily ruffled, yet the excitement was transient, and the cause of it speedily forgotten.

One of the most prominent traits in the character of Galileo was his invincible love of truth, and his abhorrence of that spiritual despotism which had so long brooded over Europe. His views, however, were too liberal, and too far in advance of the age which he adorned; and however much we may admire the noble spirit which he evinced, and the personal sacrifices which he made, in his struggle for truth, we must yet lament the hotness of his zeal and the temerity of his onset. In his contest with the Church of Rome, he fell under her victorious banner; and though his cause was that of truth, and hers that of superstition, yet the sympathy of Europe was not roused by his misfortunes. Under the sagacious and peaceful sway of Copernicus, astronomy had effected a glorious triumph over the dogmas of the Church; but under the bold and uncompromising sceptre of Galileo all her conquests were irrecoverably lost.

The scientific character of Galileo, and his method of investigating truth, demand our warmest admiration. The number and ingenuity of his inventions, the brilliant discoveries which he made in the heavens, and the depth and beauty of his researches respecting the laws of motion, have gained him the admiration of every succeeding age, and have placed him next to Newton in the lists of original and inventive genius. To this high rank he was doubtless elevated by the inductive processes which he followed in all his inquiries. Under the sure guidance of observation and experiment, he advanced to general laws; and if Bacon had never lived, the student of nature Would have found, in the writings and labours of Galileo, not only the boasted principles of the inductive philosophy, but also their practical application to the highest efforts of invention and discovery.