Popular Science Monthly/Volume 66/February 1905/Galileo II

by Edward Singleton Holden

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GALILEO. II.

By Dr. EDWARD S. HOLDEN,

U. S. MILITARY ACADEMY, WEST POINT, N. Y.

Galileo in the Sidereus Nuncius (1610) gives this account of the invention of the telescope:

A report reached my ears that a Dutchman had constructed a telescope, by the aid of which visible objects, although at a great distance from the observer, were seen distinctly as if near.... A few days after, I received confirmation of the report in a letter... which finally determined me to inquire into the principle of the telescope^[1] and then to consider the means by which I might compass the invention of a similar instrument, which, in a little while, I succeeded in doing, through deep study of the theory of refraction.... At length I succeeded in constructing for myself an instrument so superior that objects seen through it appeared... more than thirty times nearer than if viewed by the natural powers of sight alone.

On the title page of his book the telescope is described as 'lately invented by him.' This claim Galileo does not make, but in subsequent years it was charged by his enemies that he claimed credit not his due, and the charge perpetually reappears. The amazing discoveries of this memorable year are enumerated on the title page in question.

The Sidereal Messinger (Nuncius Sidereus), unfolding great and very wonderful spectacles and offering them to the consideration of every one, especially of philosophers and astronomers; being such as have been observed by Galileo Galilei... by the assistance of a perspective glass lately invented by him; namely, in the face of the Moon, an innumerable number of fixed stars, the Milky Way, and nebulous stars, but especially respecting four Planets that revolve about Jupiter at different intervals and periods with a wonderful celerity; which, hitherto not known to any one, the author has recently been the first to discover and has decreed to call the Medicean Stars. (Venice, 1610.)

The surface of the moon was covered with brilliant and dark areas as the peacock's tail with spots. Perhaps the moon has an atmosphere, he says. The heights of lunar mountains can be fixed by measuring their shadows. The ashy-light of the moon ('old moon in the new moon's arms') is perhaps caused by a lunar twilight. He gives Leonardo da Vinci's explanation also—the true one—that it is caused by earth-light reflected to the moon and back to us. The stars appear as points of light, the planets as small discs. The telescope brings countless new stars to light. In the belt and sword of Orion he sees eighty stars where only seven were known before; in the Pleiades forty instead of six or seven. The Milky Way is a multitude of faint stars clustered together. The nebulæ of Orion and Praesepe are formed of stars. His discovery of the moons of Jupiter dates from January 7, 1610, when three of them were seen. They describe circular orbits about their planet. Jupiter, like each of the planets, has an atmosphere, he says. His telescope was not perfect enough to show this. It is a deduction from analogy.

New discoveries soon followed in respect to Saturn (Dec., 1610) and Venus (Jan., 1611), and they were announced in anagrams as follows:

Smaismrmilmepoetalevmibvnenvgttaviras.
Altissimvm planetam tergeminvm observavi.
(I have observed the highest planet—Saturn—to be tri-form.)
Hæc immatura à me jam feustra leguntur, O. Y.
Cynthia figuras aemulatur mater amorum.
(The mother of the loves—Venus—emulates the figure of Cynthia—the Moon.)

The latter discovery was of capital importance. If the planet Venus revolved about the sun as Copernicus had said, it must show phases like the moon. The phases, invisible to Copernicus, were revealed by the telescope. They occurred at the precise times required to demonstrate the truth of his theory. It was now no longer a theory. It was proved. From this moment no competent witness could doubt the truth of the Copernican system—Galileo less than any one.

An opportunity unique in the history of the world was presented to Galileo and he utilized it to the full. He went from triumph to triumph. The phases of Venus, the mountains of the moon, the constitution of the Milky Way, the tricorporate figure of Saturn, the solar spots, the moons of Jupiter, were death-blows to the systems of Aristotle and of Ptolemy, and were skilfully utilized to establish the system of Copernicus. That system rests, for us, not on the telescopic discoveries of Galileo, but on the working out of its details by Kepler and Newton. To the Italians of Galileo's day Kepler was all but unknown; it is even doubtful whether Galileo appreciated Kepler's splendid discoveries; it is, at any rate, certain that he never publicly mentioned them with praise.

The mere fact that the number of planets and satellites was increased by Galileo's telescope from seven to eleven was another blow to ancient superstitions. Seven was a mystic and magical number. It had relations even to Christianity, so his contemporaries thought. The seven golden candlesticks of Revelations were the seven planets. We can form some idea of the hold of certain magical numbers on the imaginations of our ancestors by remembering that when Huyghens discovered a satellite to Saturn—thus raising the number of celestial bodies to twelve—he looked no more, ‘because twelve was universally admitted to be a perfect number.’ There were six planets and six satellites and he ventured to predict that no more would be discovered. Huyghens died in the year 1695. He was the foremost man of science on the continent of Europe.

In 1610 Galileo had seen Saturn ‘tricorporate’—in December, 1612, he writes:

Looking on Saturn 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 time mocked me, and so many others who have so 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 recognized their impossibilities. I cannot resolve what to say in a juncture 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.

The explanation of the disappearance of the ansæ of Saturn's ring was not given until 1656 (by Huyghens). Galileo's telescope was not sufficiently perfect and he died without solving what was a mere riddle to him.

The spots on the sun were first seen by Galileo, though they were first described by others (Fabritius, Schemer). In April, 1611, Galileo exhibited them at Rome to an audience of notabilities. His own observations had convinced him, he says, that the spots were real; that they were not fixed at one part of the solar globe; that they had motions; he sees no reason to doubt that they are attached to the surface of the sun; he believes that they form at the sun's surface, are dissipated and may reappear. By August, 1612, he made other observations which confirmed his earlier conjectures. Their motions prove that the sun is spherical and that it turns on an axis. He notes also that the spots all lie within certain special zones of latitude. He observes the sun by projection—by receiving its image on a sheet of cardboard. Certain large spots can be seen by the naked eye, but by an inveterate prejudice that the heavenly bodies are incorruptible, they have not been remarked; to the shame of astronomers, he says, such appearances have previously been taken for Mercury in transit over the solar disc.

Galileo's discoveries were received with incredulity by the wisest men of Italy. The warm-hearted Kepler (April, 1610) was the first to recognize ‘the divinity of his genius.’ Little by little they made their way as Galileo demonstrated them triumphantly to friends and enemies. Arguments of all sorts were brought against them and against the heliocentric theory which they supported.

Animals, which move, have limbs and muscles; the earth has no limbs and muscles, therefore it does not move. It is angels who make Saturn, Jupiter, the sun, etc., turn round. If the earth revolved, it must, also, have an angel in the center to set it in motion; but only devils live there; it would therefore be a devil who would impart motion to the earth. . . . (Scipio Chiaramonti.)

Since it can be certainly gathered from Scripture that the heavens move above the earth, and since a circular motion requires something fixed around which to move. . . the earth is at the center of the universe. (Polocco, 1644.)

If the earth is a planet, and only one among several planets, it can not be that any such great things have been done especially for it as the Christian doctrine teaches. If there are other planets, since God makes nothing in vain, they must be inhabited; but how can their inhabitants be descended from Adam? How can they trace back their origin to Noah's ark? How can they have been redeemed by the Savior?

The last paragraph is probably an answer to Galileo's opinion (December, 1612) that the moon and planets may be inhabited, though by creatures different from ourselves. Galileo writes to Kepler (August, 1610):

You are the first and almost the only person who. . . has given entire credence to my statements. . . . We will not trouble ourselves about the abuse of the multitude. . . . In Pisa, Florence, Bologna, Venice and Padua many have seen the planets; but all are silent on the subject and undecided. . . . What is to be done?. . . I think, my Kepler, we will laugh at the extraordinary stupidity of the multitude. What do you say to the leading philosophers of the faculty here, to whom I have offered a thousand times to show my studies, but who. . . have never consented to look at planets, nor Moon, nor telescope? Verily, just as serpents close their ears, so do these men close their eyes to the light of truth. . . . People of this sort think that philosophy is a kind of book like the Aeneid or the Odyssey and that the truth is to be sought, not in the universe, not in nature, but (I use their own words) by comparing texts! How you would laugh, he goes on, if you heard the first philosopher of Pisa trying to ‘argue the new planets out of heaven.’

While Galileo was teaching the elements of Euclid at Padua his colleague, Cremonini, was expounding Aristotle's de Cœlo. It was Cremonini who refused to look at the newly discovered satellites of Jupiter through the telescope, alleging as a reason that their existence was quite contrary to Aristotle's philosophy. It was the same Cremonini who, in 1619, with a dignity and firmness that must be sincerely admired, flatly refused to change the substance of his university lectures at the demand of the Grand Inquisitor of Padua. His duty was to expound the words of Aristotle as he found them, he said; he declined to teach as Aristotle's any doctrine that he did not sincerely believe to be the master's. Let this manly stand be counted off against his refusal to be convinced against authority. He is reputed to have been the last scholastic. When he died, in 1631, there was no one to take his place. The times had changed. We are accustomed to attribute all the merit of the change to Galileo, whose career so brilliantly represents what was best in the new scientific spirit. It is impossible to declare what the movement of the world would have been had Galileo never lived. It would, perhaps, have been much the same. A company of less brilliant men would, perhaps, have done Galileo's work, taking a century for the task. Scholasticism was already moribund; the telescope was invented; the time was ripe; Kepler had already discovered his great laws of planetary motion; who can doubt that scholars would have arisen to fill the opening opportunity?

Gradually the fame of Galileo rose to a great height. He became the best known man in Europe. His lecture rooms were crowded. At Easter, 1610, he showed the Medicean stars to Cosmo II in Florence, and in May he writes a letter describing the work that he has projected—treatises on the constitution of the world, on mechanical motion, on sound, color, vision, tides, fortification, tactics, artillery, sieges, surveying, etc.^[2] This letter soon brought an offer from the Grand Duke to appoint Galileo first philosopher and mathematician at the University of Pisa at a salary of 1,000 scudi. He is not to be obliged to reside at Pisa—and in fact his duties were usually performed by substitutes.

In July, 1610, Galileo left the service of Venice for that of Florence. It was a sad exchange for him. Venice was the only state in Italy that dared to stand up against the power of Rome. There were weighty reasons of state why the Duke of Florence could not do so. The Jesuits had been banished from the soil of Venice (1606) ‘for ever.’ They were all powerful in Rome and in Florence. It is evident from letters of this time that Galileo's desertion of Padua produced an unfavorable impression of self-seeking even among his friends.

Galileo's visit to Rome in March, 1611, was a veritable triumph for him. His expenses were paid by the court, he was lodged with the Tuscan ambassador, and received with the greatest honor by the Pope (Paul V.) and the cardinals, including Cardinal Barberini, the future Pope Urban VIII. To them he showed his discoveries. They were convinced and interested. At the request of Cardinal Robert Bellarmine, four learned men of the Roman College (Clavius among them) reported on what they had seen through the telescope and fully confirmed his observations. This report is of great importance, since it was, in effect, a sanction by the Church itself. Galileo was received a member of the Accademia dei Lincei, and its president, Prince Cesi, became his lifelong friend. The Cardinal del Monte writes to the Grand Duke of Florence (May 31, 1611) that Galileo had given great satisfaction: ‘Were we still living under the ancient republic of Rome I verily believe there would have been a column on the capitol erected in his honor.’ Galileo was at the top of the wave of fortune to all appearance. At this very moment, however, Cremonini's trial was going on before the Roman Inquisition and on the records is an inquiry whether Cremonini and Galileo were in any relation with each other. He was already suspected of heresy. His friendship would, even then, have been prejudicial. By 1613 Galileo was aware that there was a league of his Florentine enemies against him. In a letter to Prince Cesi he makes light of it. ‘I laugh at it,’ he says, but it was none the less serious. It was based on religious scruples, but stirred to action by bitter personal animosities.

Brilliant successes, like those of Galileo, raise up an army of enemies. He was haughty with his own. Sure of his talents, his fortune and his powerful patrons in church and state, he had no managements for any one. ‘The wind is fair: now is the time to take in sail,’ is a maxim that he would have scorned. Of Aristotle's virtues he practised magnificence, not prudence. His colleagues in the universities were mostly Aristotelians. The heretical and Arab Aristotle had been banished; the Greek Aristotle reigned supreme. Galileo handled his opponents harshly. He was proud; he had a right to be. He was haughty; it led to his fall. When certain chosen astronomers of Italy were asked in 1615 by the Holy Office to report on his system, the report was adverse. Science and pseudo-science were in conflict and the latter won. The Aristotelianism of the universities was bound closely to that of the church. In attacking the orthodox Aristotle, Galileo attacked—or was supposed to have attacked—orthodoxy itself. His enemies were vanquished in philosophy; they dragged in texts of scripture to support the weakness of their science. Galileo met them on this ground also, which was a fatal error. He was no more competent to discuss texts of scripture than they to decide upon points of science.

Father Castelli, an ardent friend of Galileo's, had been appointed to be professor of mathematics at Pisa (1613). At a dinner at the Ducal Palace (December, 1613) the conversation turned on astronomical matters. Did the Medicean stars really exist? asked the Dowager Duchess Christine. The professor of physics in the university reluctantly admitted that they did—that he had seen them. Castelli then praised Galileo's splendid discovery. The professor whispered something to the duchess to insinuate that while the discoveries might be true, the conclusion in favor of the Copernican theory was certainly contrary to scripture. Castelli was called upon to reply and made a brilliant answer. The Grand Duke and most of those present were convinced. Castelli reports all this to Galileo, and Galileo writes in reply (December 21, 1613) a long and eloquent letter on the subject. The original of this letter was never found, although the Inquisition made diligent search for it. Many authentic copies were circulated, however.^[3] The question of the place of the Bible in scientific questions is discussed. Galileo is a good Catholic; the scriptures can not lie or err, he says. But the expositors are fallible. They will fall into error, nay into heresy, if they interpret Holy Writ literally. Both scriptures and external nature owe their origin to the Divine Word.

“It was necessary, however, in Holy Scripture, in order to accommodate itself to the understanding of the majority to say many things which apparently differ from the precise meaning. Nature, on the contrary, is inexorable and unchangeable, and cares not whether her hidden causes and modes of working are intelligible to the human understanding or not, and never deviates from her prescribed laws.” It appears to me, therefore, says Galileo, that no effect of nature, which experience places before our eyes, or is the necessary conclusion derived from evidence, should be rendered doubtful by passages of Scripture which contain thousands of words admitting of various interpretations, for every sentence of Scripture is not bound by such rigid laws as is every effect of Nature. . . . Since two truths can obviously never contradict each other, it is the part of wise interpreters of Holy Scripture to take the pains to find out the real meaning of its statements in accordance with the conclusions regarding nature which are quite certain, either from the clear evidence of sense or from necessary demonstration. As therefore the Bible, although dictated by the Holy Spirit, admits. . . in many passages of an interpretation other than the literal one and as, moreover, we can not maintain with certainty that all interpreters are inspired by God, I think it would be the part of wisdom not to allow any one to apply passages of Scripture in such a way as to force them to support, as true, conclusions concerning nature, the contrary of which may afterwards be revealed by the evidences of our senses or by necessary demonstration. Who will set bounds to man's understanding? Who can assure us that everything that can be known in the world is known already?. . . I am inclined to think that the authority of Holy Writ is intended to convince men of those truths which are necessary for their salvation which, being far above man's understanding can not be made credible by any learning, or by any other means than revelation by the Holy Spirit. But that the same God who has endowed us with senses, reason and understanding, does not permit us to use them and desires to acquaint us in any other way with such knowledge as we are in a position to acquire for ourselves by means of those faculties, that it seems to me I am not bound to believe, especially concerning those sciences about which the Holy Scriptures contain only small fragments and varying conclusions; and this is precisely the case with astronomy, of which there is so little that the planets are not even all enumerated

This noble declaration of the independence of man's reason, written in 1613, marks the highest insight yet reached by the human spirit in this regard. It is the greatest product of Galileo's philosophical genius. It was written in haste, he says, yet its form is perfect and convincing. It is the weighty expression of convictions felt, pondered over and matured. It precisely expresses the attitude of the generations that followed Darwin. No considerable body of men ever held it before that day. It delighted Castelli and a few of the more enlightened of Galileo's circle. His enemies received it with breathless, uncomprehending rage. They sought for flaws in the argument and, unhappily, they had not far to seek. For, not content with these general principles, Galileo went on to explain certain passages of scripture in a fashion that, at the best, was weak and unconvincing, almost disingenuous. The famous passage in Joshua, ‘The sun stood still in the midst of heaven (and hasted not to go down about a whole day)’ is expounded by first suppressing the words in parentheses, next by a wire-drawn argument to prove that Joshua's command was given when the sun was near setting (which disagrees with the words purposely omitted) and that ‘the midst of heaven’ does not mean the place of the sun near noon, but its central place in space among the planets. Hence, says Galileo, this passage actually demonstrates that the sun occupies the center of the world, and refutes Ptolemy. The plain meaning of the verse was distorted by a wilful suppression. It is said in the XIX. Psalm ‘The sun's going forth is from the end of the heaven and his circuit unto the ends of it.’ Galileo explained this to mean that the sun is the nuptial bed, and the bridegroom coming out of his chamber rejoicing is the light of the sun—his rays—not the sun himself. There is not a shade of reason for this arbitrary interpretation. It is not convincing to us; it was abhorrent to his adversaries. Is it any wonder that they loudly proclaimed their intention to protect the words of the Bible from the profane interpretations of laymen? Into the quicksand of theological interpretation Galileo had no call to enter. He should have declined the controversy thrust upon him by his enemies on the simple ground that he was no more fitted to deal with theology than his adversaries with science. This was, however, not his belief, and he accepted their challenge. By so doing he quite nullified the effect of his noble stand upon general principles. Radical and bold as this stand was, he could have maintained it as Cremonini had maintained his own upon a similar issue. At this critical point in his career two roads were open. He recklessly, even presumptuously, chose the wrong one. All his tribulations are the result of this choice. In two letters of February 16 and March 28, 1615, Galileo, writing to Mgr. Dini, regrets that he has been forced to defend his system against religious scruples. In his letter to the Grand Duchess Christine he had said ‘the professors of theology should not assume authority on subjects which they have not studied.’ It never so much as crossed his mind that his own interpretations of the texts of Joshua and the Psalms were like assumptions of authority. In all that follows it must not be forgotten that Galileo had the free choice of leaving the scriptural interpretations alone and of confining himself to science and to philosophical considerations of a general nature. He chose to enter the lists, and there is every reason to believe that he felt sure of winning.

Galileo's case recalls that of Roger Bacon, nearly four centuries earlier. The science of both these men of genius was, in the main and essentially, illuminating and correct. It was, for both of them, opposed by ignorant men who feared that which they could not understand. Both of them went out of the province in which alone they had authority, to enter another in which their contemporaries and fellows were at least as well able to judge as they. Both of them overbore and offended their colleagues by harshness. When they were brought to trial those very colleagues were, in turn, accusers, jurors and judges. A like fate befell both.

The history of Jordano Bruno does not fall within the scope of this article and need be considered only so far as it affected the contemporaries of Galileo, and Galileo himself. The following paragraphs from Draper's ‘Intellectual Development of Europe’ give the views of a writer who is inclined to present Bruno's history in the most favorable light. The foot notes are my own.

Against the opposition it had to encounter, the heliocentric theory made its way slowly at first. Among those who did adopt it were some whose connection served rather to retard its progress, because of the ultraism of their views, or the doubtfulness of their social position. Such was Bruno, who contributed largely to its introduction into England, and who was the author of a work on the Plurality of Worlds, and of the conception that every star is a sun, having opaque planets revolving about it—a conception to which the Copernican system suggestively leads. Bruno was born (1550) seven years after the death of Copernicus. He became a Dominican, but, like so many other thoughful men of the times, was led into heresy on the doctrine of transubstantiation.^[4] Not concealing his opinions he was persecuted, fled, and led a vagabond life in foreign countries,^[5] testifying that wherever he went he found scepticism under the polish of hypocrisy, and that he fought not against the belief of men, but against their pretended belief. For teaching the rotation of the earth he had to flee to Switzerland, and thence to England, where, at Oxford, he gave lectures on Cosmology. Driven from England, France and Germany in succession, he ventured in his extremity to return to Italy, and was arrested in Venice where he was kept in prison in the Piombi for six years without books, or paper, or friends. Meantime the Inquisition demanded him as having written heretical works. He was therefore surrendered to Rome, and, after a further imprisonment of two years, tried, excommunicated, and delivered over to the secular authorities, to be punished ‘as mercifully as possible and without the shedding of his blood,’ the abominable formula for burning a man alive. He had collected all the observations that had been made respecting the new star in Cassiopeia, 1572; he had taught that space is infinite, and that it is filled with self-luminous and opaque worlds many of them inhabited—this being his capital offense.^[6] He believed that the world is animated by an intelligent soul, the cause of forms but not of matter; that it lives in all things, even such as seem not to live; that everything is ready to become organized; that matter is the mother of forms and then their grave; that matter and the soul of the world together constitute God. His ideas were therefore pantheistic, ‘Est Deus in nobis.’ In his Cena delle Cenere he insists that the Scripture was not intended to teach science, but morals only. The severity with which he was treated was provoked by his asseverations that he was struggling with an orthodoxy that had neither morality nor belief. This was the aim of his work entitled ‘The Triumphant Beast.’ He was burned at Rome, February 16, 1600.

In 1612 Galileo writes to Kepler that epicycles and eccentrics are not chimerical; ‘not only are there many motions in eccentrics and epicycles, but there are no other motions.’ This, written three years after Kepler had sent him his Theory of Mars containing the proof of elliptic motion, shows that Galileo had not yet appreciated Kepler's revolutionary discoveries. It is doubtful if he ever did so. He makes no effective use of them in his arguments in favor of the Copernican doctrines.

In the meantime busy enemies were stirring up trouble. The letter to Castelli gave great offense. The Bishop of Fiesole became enraged at Copernicus and was much surprised to learn that he had been dead for eighty years. A Dominican friar, P. Caccini, preached a violent sermon against Galileo (1614) on the text Viri Galilæi quid statis aspicientes in cœlum? Ye men of Galilee, why stand ye gazing up into Heaven? Castelli was advised by the archbishop of Pisa, ‘for his welfare,’ ‘if he wished to escape ruin,’ to abandon the Copernican opinion, because that opinion, besides being an absurdity, was perilous, scandalous, rash, heretical and contrary to scripture.

Another Dominican friar, Lorini, addressed to Cardinal Mellini, president of the Congregation of the Index, a denunciation of ‘the Galileists,’ who hold the doctrine of Copernicus. The congregation accordingly (February, 1619) opened a secret inquiry. A copy of Galileo's letter to Castelli was examined by the consultator of the Holy Office, who pronounced that some phrases of it looked ill at first sight, but that they were capable of interpretation in a good sense, and did not deviate from Catholic doctrine. Caccini was summoned to Rome as a witness and gave evidence, most of which was found to be baseless (November, 1615) and was disregarded.

Early in the same year Galileo had sent copies of the letter to Castelli to friends in Rome. It was greatly admired; but his friends, one and all, strenuously advised him to keep to philosophy and to avoid religious discussion. Prince Cesi expressly warns him to avoid all mention of the Copernican theory, for Cardinal Bellarmine—a good, great and powerful prince of the Church—had told him that in his opinion the theory was heretical and contrary to scripture. Cardinals Barberini, Del Monte and Bellarmine assured Galileo's Roman friends that so long as he confined himself to scientific questions and did not enter into theological interpretations of the Bible he had nothing to fear (August, 1615). All these cardinals were very friendly to Galileo personally, and their friendship stood him in good stead. Their attitude was representative of that of the church. So long as religion was not attacked science was to be free. Any assault on doctrine was to be repelled with vigor, and at all costs. Theological interpretation was not to be permitted to laymen. That was a business reserved by the church.

A Carmelite monk, Foscarini, printed in 1615 a letter on ‘the opinion of the Pythagoreans and of Copernicus of the mobility of the earth and the stability of the sun,’ which was widely read and quickly came to a second edition. The Inquisition was at this time considering Foscarini's book also. Galileo felt that his presence at Rome would be advantageous, and in December, 1615, he set out provided with letters of introduction from the Grand Duke to dignitaries, including the Tuscan ambassador, Guicciardini. He was received with honor as a celebrity. With no great effort he freed himself from all personal difficulties and was able to report (February 6, 1616) that the monk Caccini had made him a formal visit to ask his pardon. On the same day he writes to the Tuscan Secretary of State, Piechena: “My business, so far as it relates to myself, is completed. All the exalted personages who have been conducting it have told me so plainly and in a most obliging manner. . . . So far as this point is concerned, therefore, I might return home without delay.”

He goes on to say that it is proposed to pass judgment upon the Copernician doctrine, and that it is his conviction that he may be of use in the investigation of the matter, on account of his scientific knowledge. Accordingly he proposes to stay. He had been personally vindicated. It was his ardent desire to convert the Romans to the heliocentric theory. This he attempted by giving private lectures in many of the great houses of Rome. His lectures began by stating all the arguments in favor of Ptolemy's system and then went on to demolish them one by one, leaving nothing standing. The lectures were admired by many great folk, and Galileo gained a great personal success for the time. His very success made his well-wishers uneasy and unquiet.

Before Galileo's visit, Fra Paolo Sarpi, professor of philosophy in Venice, distinguished as a champion of free thought and as a friend of Galileo had written: “I hear that Galileo is going to Rome, where he is invited by several Cardinals to explain his new discoveries in the heavens. I fear much that, in such a case, he may develop the reasons that lead him to prefer the doctrine of Copernicus, which will be far from pleasing to the Jesuits and other monks. They have changed what was only a question of physics and astronomy into a theological question, and I foresee, with great vexation, that Galileo, in order to live in peace, and not labeled as heretic and excommunicate, will be constrained to abjure his real sentiments on this matter. A day will come, of that I am almost sure, when enlightened men will deplore the misfortune of Galileo and the injustice done to so great a man. But, pending that day, he must suffer, and he must not complain otherwise than secretly.”

The Tuscan ambassador at Rome was anxious to be rid of Galileo, and in many letters reports that it were well he returned home. He hints that Galileo's course may even bring dangers to Tuscany; he can not ‘approve that we should expose ourselves to such annoyances and dangers without very good reason.’ He insinuates that Cardinal Carlo de Medici may be compromised (March 4, 1616). “Galileo seems disposed to emulate the monks in obstinacy, and to contend with personages who can not be attacked without ruining yourself; we shall soon hear at Florence that he has madly tumbled into some abyss or other.” “The moment is badly chosen to promulgate a philosophical idea.” The Grand Duke, from friendliness to Galileo and in fear of untoward complications, gave instructions for his recall, which were conveyed in a dispatch from the ducal secretary: “You have had enough of monkish persecutions. . . . His Highness fears that your longer tarrying at Rome might involve you in difficulties, and would therefore be glad, as you have so far come honorably out of the affair, if you would not tease the sleeping dog any more, and would return here as soon as possible. For there are rumors flying about which we do not like, and the monks are all powerful.” Galileo set out for Florence on the fourth of April, 1616.

Let us stop for a moment to inquire what the course of affairs would have been if Galileo, whose personal affairs were honorably concluded on February 6, had thereupon returned to Florence. He had renewed old friendships; he had formed new ones; he was esteemed and regarded by the Pope and the most influential of the Cardinals. His enemies in Florence were utterly silenced. His accuser, Caccini, had made the humblest apologies. The Grand Duke and most of the court were his admiring friends. He had every freedom for research if only he would leave the interpretation of scripture to theological experts. ‘Write freely, but keep outside the sacristy’ his friends advised. Why did he remain in Rome? To convert the Congregation of the Index to Copernicanism? This would have been a triumph for science, and a personal triumph as well. The Roman Curia had absolutely no interest in science as such. They were determined that religion should not suffer. Galileo's brilliant lectures were not conceived in the spirit that convinces. He silenced opposition by sarcasm. A second crisis in Galileo's affairs dates from this period (February, March, 1615).

Before this date momentous action had been taken by the Inquisition. On February 19 the Qualificators of the Holy Office had been summoned to give their opinion on two propositions based on Galileo's treatise on the Solar Spots:

I. That the sun is the center of the world and immovable from its place.

II. That the earth is not the center of the world, nor immovable, but moves, and also with a diurnal motion.

The Qualificators were to give their opinion as theological and philosophical experts, and gave it four days afterwards. The astronomer Riccioli declares that the opinions of astronomical experts were also obtained and that the judgment of the Holy Office was based upon them (Delambre: Histoire de l'Astronomie Moderne, i., 680). There is no reason to doubt the assertion. It is exceedingly important as showing that the Inquisition took the best expert advice known to them before action. This significant fact is not mentioned in any of the Warfare-of-Science books, nor even by so careful an historian as Gebler.^[7]

The scientific value of the expert astronomical opinion was, of course, exactly nil. It was given, probably, by Aristotelians, personally inimical to Galileo, and fully committed to the Ptolemaic system. It was, equally of course, adverse to Galileo. They may well have quoted the dictum of Tycho Brahe that the system of Copernicus was ‘absurd and contrary to Holy Writ’ since the judgment recites these very words. On March 5, 1616, the ‘De Revolutionibus’ of Copernicus and another work by Diego di Zuniga were suspended by the Congregation of the Index ‘until they be corrected,’ and Foscarini's book was ‘altogether prohibited and condemned’ as well as ‘all other works’ in which the Copernican opinion is taught. On February 25 the Pope directed ‘Cardinal Bellarmine to summon before him the said Galileo and to admonish him to abandon the said opinion; and, in case of his refusal to obey, that the Commissary is to intimate to him, before a notary and witnesses, a command to abstain altogether from teaching or defending this opinion and doctrine, and even from discussing it; and if he do not acquiesce therein, that he is to be imprisoned.’ This document is followed in the Vatican MS. by another: “Friday, the 26th (February, 1616). At the Palace, the usual residence of the Lord Cardinal Bellarmine, the said Galileo, having been summoned and brought before the said Lord Cardinal, was in the presence of the Most Rev'd Michael Angelo Segnezzio, . . . Commissary-General of the Holy Office, by the said Cardinal warned of the error of the aforesaid opinion and admonished to abandon it; and immediately thereafter, before me and before witnesses, the Lord Cardinal Bellarmine being still present, the said Galileo was by the said Commissary commanded and enjoined . . . to relinquish altogether the said opinion . . .; nor henceforth to hold, teach or defend it in any way whatsoever, verbally or in writing; otherwise proceedings would be taken against him in the Holy Office; which injunction the said Galileo acquiesced in and promised to obey. Done at Rome in the place above said, in presence of (two persons named) witnesses.” This annotation was long supposed to have been fabricated in 1632 to meet new conditions then arising. It is, however, entirely genuine. (Gebler's ‘Galileo,’ Appendix III.)

The exact wording is to be noted. Upon this admonition the subsequent fate of Galileo hangs.

(To be continued.)

1. Galileo uses the words perspicillum, occhiale, etc., for the instrument. The word telescope was invented to describe the new instrument by Demiscianus at the request of Prince Cesi, president of the Accademia dei Lincei about 1612. The telescope itself was invented by Hans Lippershey.
2. Compare the letter of Leonardo da Vinci to the Duke of Milan reciting the labors that he was ready to undertake in his service.
3. The letter was subsequently expanded and addressed in its new form to the Grand Duchess Christine (1614).
4. Bruno was twice disciplined for ‘open and avowed’ heresy during the thirteen years of his cloister life (1563-1576). He denied the personality of Christ for one thing.
5. Toulouse, Paris (1579 and 1585), Oxford (1583), Wittenburg (1587), Prague (1588), Helmstadt (1589), Frankfort (1590), Marburg (1586), Venice (1592), Rome (1593). These dates correct some errors of the text.
6. One of them; his pantheistic ideas were, perhaps, his worst heresies in the eyes of his judges. His doctrine that space is infinite filled the pious Kepler, as well as Bruno's Roman judges, with ‘horror.’ Bruno's works were full of opinions that were abhorrent to all religious people of his time. He was inclined to pronounce in favor of polygamy, and he advocated a species of socialism. Religion he made essentially synonymous with intellectual culture, neglecting moral discipline and spiritual feeling.
7. Gebler records, however the action of Cardinal Gaetano who, in 1616, applied to Thomas Campanella, a learned Dominican and a friend of Galileo's, for an opinion upon the relation of the Copernican theory of Holy Scripture. Campanella's ‘Apology’ for Galileo was all in his favor and reconciled, in form at least, Copernican science with the Bible. It was overweighed by other reports. It is worth recording that Campanella was not permitted to publish this ‘Apology’ in Italy and was obliged to disavow an edition which appeared at Frankfort.