ness and moderation in speaking of the characters and conduct of those to whom he was opposed. Galileo Galilei, born at Pisa in 1564. was descended from a patrician, though decayed family, some of whose members had filled high civic offices in Florence. ent brief but interesting Memoirs; for though their services to science are distinctly set forth, and on the whole accurately appreciated, they are not dwelt upon at such length, or with so much detail, as to interfere with the popular character of the work. He does not profess to have had access to any new sources of information, He was originally destined for commerce; or to have placed the already known facts but his studious disposition and promising in a new point of view; he has undertaken talents led his father, Vincenzo Galilei, to no laborious researches for the purpose of entertain visions of success in a liberal prosettling controverted points in history, or fession; and at the age of seventeen, he detecting minute errors or omissions in the was sent to the university of Pisa to study accounts of previous biographers. In fact, medicine. His taste for geometry is said the field had already been so diligently to have been developed by accidentally overgleaned, as to leave but small hopes of suc- hearing a lesson given by the Abbé Ricci cess in any attempt at novelty. The work to his pupils, the pages of the Grand Duke derives its interest from the vivid portrai- of Tuscany. Ricci happened to be a friend tures it places before us of the characters of Vincenzo Galilei; and, on becoming of men whose labors occupy a large space acquainted with the circumstance, and the in the history of science, and whose en- progress already made by the young aspideavors to enlighten the world were attend-rant, admitted him to his course, and ened with so many personal sacrifices. It is couraged him to persevere. The study of written in an agreeable style; it abounds with traits of good feeling and generous sympathy; and, what may be regarded as of importance in a popular work, it represents science and its pursuits under an attractive and dignified aspect. Euclid was followed by that of Archimedes; and after some ineffectual attempts on the part of his father to recall him to his professional studies, he was allowed to follow the bent of his genius. But Vincenzo, being burdened with a numerous family, was unable to maintain his son at Pisa; he applied for a bursary, and was disappointed; and Galileo was compelled to leave the university without taking his The life of Galileo, whom Sir David Brewster places at the head of his martyrs, has been given by his numerous biographers with great minuteness of detail. The materials for the scientific portion are of Doctor's degree. course collected from his various writings Galileo's first essay in science was a treaand literary correspondence; the anecdotes tise on the hydrostatical balance. This and personal traits rest chiefly on the au- production fell into the hands of Guido thority of Viviani and Gherardini, the for- Ubaldi, who forthwith conceived a friendmer of whom was one of his pupils, and ship for the young author, and procured revered his memory with a species of idola- for him the appointment of lecturer on try. Until recently, there was no good mathematics at Pisa, with a salary of sixty account of his life and discoveries in Eng- crowns. In this office he soon made himlish; but the want was ably supplied by the self conspicuous for the freedom and boldelaborate though somewhat discursive trea-ness of his attacks on the mechanical doctise, in the Library of Useful Knowledge trines of Aristotle, whereby he excited the (1829); a work which it is but justice to suspicions, and provoked the hatred of a sty, has afforded our author considerable facilities in preparing the present Memoir. The recent historical work of Libri has an account of Galileo which is very valuable from its fulness and research, and the care which has been taken to quote the original it was the custom (as it had been in the authorities for the various statements and middle ages) to engage professors for a anecdotes recorded; but unfortunately the term of years. Galileo's appointment was author is a partisan, whose zeal to magnify for six years; but when the first period of his hero causes him to lose sight of all fair strong party in the university. In 1592, he his engagement had expired, he was reelected for another period of six years, with an increased salary of 320 florins; and in 1606 he was a third time appointed, and his salary raised to 520 florins. His of refraction; and that by applying two popularity by this time had become so great, spectacle glasses of a particular kind to a that his audience could not be accommodat-leaden tube, he was immediately in possesed in the spacious lecture-rooms, and he was frequently obliged to adjourn to the open air.' sion of a telescope which magnified three times. According to this account, Galileo was a re-inventor of the telescope. He himIn 1609, Galileo, from some obscure self claims no other merit than that of dihints, found out the construction of the vining the construction, and improving the telescope. The instrument excited intense instrument. He affirms that he had never curiosity at Venice; and he presented one seen any of the Dutch telescopes; and alto the Senate, who acknowledged the though, as remarked by Sir David Brewster, present by a mandate, conferring on him there is no reason to doubt his assertion, it for life his professorship at Padua, and appears from various evidence that more than generously raising his salary from 520 to one telescope had previously been brought 1000 florins.' In the following year he was from Holland to Italy; whence it has been induced, by offers from Cosmo, Grand conceived to be quite possible that, withDuke of Tuscany, to return to his native out having actually seen the instrument, he state; and he took up his residence at Flo- may have received such information with rence, in the capacity of mathematician respect to its construction, as would render of the Grand Duke, with a salary of 1000 the discovery of the principle not altogether florins, and with no official duty excepting independent. But whether his merit in the that-which we may suppose would not re-invention of the telescope be great or press hard upon his leisure-of occasionally small, he is entitled, beyond all question, lecturing to foreign princes. This appoint-to the honor of first applying it to the exment Galileo continued to hold during the amination of the Heavens; and displaying, remainder of his life, enjoying the favor to the astonished gaze of mankind, new first of Cosmo, and afterwards of his suc-worlds and wonders, of the existence of cessor, Ferdinand II., both of whom treated which, till that time, no one had formed him with distinction; and used their influ-a conception. ence with the court of Rome to shield him The invention of the telescope was folfrom the persecutions which were raised lowed almost immediately by a crowd of asagainst him by the churchmen, and the tronomical discoveries, which, though, partisans of the Aristotelian philosophy. from our familiarity with them at the presBeing thus placed in a situation of inde-ent day, they cease to be regarded with wonpendence, and in possession of uninterrupted der, could not fail, on their first announceleisure, Galileo devoted himself with ar-ment, to excite very great admiration and dor to the study of philosophy; and it must astonishment. The first object he examined be admitted, that if there be others to whom was the moon, whose rugged and irregular physical science is indebted for more pro-surface, presenting so many points of refound investigations, and researches of great-semblance to our own earth, supplied him er difficulty, there is, perhaps, no one whose with arguments against the Aristotelian writings have more contributed to its gene-doctrine of the perfection, absolute smoothral progress, or whose name is associated withness, and incorruptible essence of the heavena greater number of brilliant discoveries. ly bodies; of which he was not slow to take adGalileo's astronomical discoveries were vantage. He next observed and pointed out the natural, it may be said the necessary, con- the remarkable difference between the telesequences of the invention of the telescope.scopic appearances of the planets and fixed With respect to the instrument itself, it stars; and the innumerable multitude of small is not easy to pronounce with certainty stars that become visible in the milky way, on the exact degree of merit he can claim the pleiades, and other nebula and clusters. in the invention. The received story is, that But of all his telescopic discoveries, that while at Venice in 1609, he heard acciden- which was regarded as the most astonishing tally of an instrument having been con- and incredible, (for their existence was denistructed in Holland, which possessed the ed, and cause shown why they could not pos property of causing distant objects to ap-sibly exist,) was the satellites of Jupiter. pear nearer to the observer; that on reflecting on the means by which this effect could be produced, he found, after a night's consideration, the explanation in the principle Four small planets revolving about a central body, and presenting so palpable and striking an analogy to the primary planets revolving about the sun, furnished an argu ment in favor of the Copernican theory, the other departments of natural philosoto which even the most bigoted followers phy, were of more importance than his telof Aristotle could scarcely withhold their escopic discoveries. Since the days of Arassent. The ring of Saturn also attracted chimedes, no advance had been made in his notice; but, in this case, he mistook the the theory of mechanics. In determining nature of the phenomenon, and supposed the law of the acceleration of falling bodthe planet to be triple. He remarked the ies, and thereby laying the foundation of horned appearance of Venus, and thereby dynamics, Galileo gave it an immense exremoved a difficulty which had occurred to tension. While yet a student at Pisa, he Copernicus himself, who perceived that, remarked the extremely important fact of if his theory were true, the inferior planets the isochronism of the pendulum; and being ought to have phases like the moon. His then engaged in medical studies, he prodiscovery of the spots on the sun has oc-posed to apply that property as a means of casioned much controversy; having been ascertaining the rate of the pulse. At a claimed by Fabricius, Scheiner, and our more mature age, he had an idea of making countryman Harriott. Galileo's claim to use of a pendulum as a regulator of clockpriority seems now generally admitted; and work; but he was ignorant of the theory he deduced from the phenomena the im- of the isochronism, which was first given portant conclusion, that the sun revolves by Huygens. The three (so called) laws on its axis in a period of about twenty- of motion, though they are not distinctly eight days. enunciated, are virtually involved in the Greatly as these discoveries have con- reasoning which he employs in his 'Diatributed to the fame of Galileo, it cannot logues on Mechanics,' published in 1638. be said that they occupied a large portion The principle of virtual velocities has of his time-having been all published usually been ascribed to him; the germ is, within three years after he was in possession however, to be found in the anterior writof the telescope. Viewing them with re-ings of his first patron and early friend, lation to the present state of knowledge, Guido Ubaldi. In mathematics he was not their intrinsic merit is not very great. an inventor; and it would seem that his They are nothing beyond what an ordinary acquirements in this department were observer, with a tolerably good telescope, scarcely equal to the state of knowledge at would be expected to make out in the the time. Delambre has remarked as extracourse of a few evenings; excepting, per- ordinary, that in his long calculations (pubhaps, the phenomena of the solar spots, lished in 1632) to prove that the new star and the motions of Jupiter's satellites, of 1572 had no parallax, he made no use which require time for their development. of Logarithms, although the tables of NaAfter the invention of the telescope, they pier, Kepler, Ursinus, and Briggs, were imply no great merit; and could not long then in existence, and would have greatly have escaped observation, although Galileo abridged his labor. In a letter to the had never lived. In fact, with the excep- Grand Duke, written in 1609, he mentions tion of the phases of Venus, and the triple several mathematical treatises on which he appearance of Saturn, they were all claim- was engaged; among others, one on the ed by other observers even in his own life- composition of continuous quantity. It is time. But, in order to appreciate them not very clear that the works alluded to correctly, we must go back to the period ever existed elsewhere than in his own at which they were made; and consider mind; but it is supposed that many of his them with reference to the ideas universal-writings have been lost, and that with rely entertained in that age. In this light, ference to the one just mentioned, Cavaltheir importance assumes a very different leri long refused to publish his own theory, character; and it will appear that to Gali- in the hope that Galileo's would be given leo must be conceded the honor, not only of to the world. On these very insufficient having made an immense addition to the grounds, Libri gives him the credit of havexisting knowledge of the heavens, but of ing imagined the calculus of indivisibles. having prepared men's minds for the recep- It is not our purpose to enumerate the tion of the true Theory of the Universe, specific services which Galileo rendered to by beating down and overthrowing the the physical sciences; and still less to prejudices by which they had been kept enter into any account of the long and enthralled for so many generations. prolix discussions with which the announceThe researches of Galileo, in some of ment of the greater part of his discoveries was followed. His claim to the gratitude persecution by which his last years were of posterity consists not so much in his embittered. actual discoveries, important though they Galileo had adopted the Copernican thewere, as in the revolution which he con-ory at an early period; and as it was not tributed to effect in philosophy, by applying the disposition of his mind long to cherish geometrical reasoning to experimental facts, any opinion in silence, keen discussions and teaching mankind to reject the dogmas on the subject had taken place between of the schools, and to appeal from the au- himself and the Peripaticians during his thority of Aristotle to reason and observa- residence at Padua. Defeated in argument, tion. It cannot, indeed, be said that he they invoked the aid of religion, and atwas either the first who followed the in- tempted to silence him by the authority of ductive method of reasoning, or who per- Scripture. The heads of the Church, ceived and denounced the worthlessness of though disliking the innovation, were rethe scholastic philosophy; but the credit luctant to commit themselves by a formal which he had gained by the telescope, and condemnation of the doctrine, and desirous the wonders it revealed, and, above all, that it should be viewed in the light of a the extraordinary elegance and perspicuity mere mathematical hypothesis. In fact, the of his writings, threw the merits of others theory of the earth's motion, so far from havinto the shade; and gave an impulse and ing met with opposition on its first promulcurrency to his opinions, which they would gation, had been received with favor by not have obtained without these accessory some of the most eminent cardinals and advantages. Considering the frequency churchmen; and Copernicus, himself a with which his name occurs in all the priest, had dedicated his great work, De scientific productions of the seventeenth Revolutionibus, to the Pope. But when century, and that it stands at the head of Galileo, who had no spiritual character, so many important discoveries both in as- began to disseminate the same doctrine, tronomy and mechanics, we may admit the the Dominicans took alarm, and forced the remark of his countryman Libri, that in Church into a reluctant declaration of science he was the master of Europe. its sentiments. In replying to the objections which his opponents drew from certain texts of Scripture, Galileo, in a letter to his friend and pupil Castelli, endeavored to prove that the expressions employed in the sacred writings were not intended to have The circumstances which entitle Galileo to be regarded as a martyr of science, are the persecutions he sustained on account of his assertion of the earth's motion; his trial, condemnation, and imprisonment, by the Inquisition; and his constrained ab-reference to astronomical systems; and that juration, in his old age, of the Copernican doctrine, which it had been the principal business of his life to establish. This episode in his history has been represented in very different colors by his biographers; some ascribing his persecution to the jealousy with which the Romish Church has always been disposed to regard the propagation of physical knowledge; while others have considered that it was provoked, if not altogether compelled, by his own imprudent conduct; which left the heads of the Church no alternative but to reduce him to silence, or abandon their pretensions to spiritual authority. Sir David Brewster has treated this subject with fairness and moderation. He is no apologist of the Inquisition; yet, on perusing his narrative, we cannot fail to see that its conduct, in this particular case, was not without circumstances of palliation; and that Galileo himself like many others who have had the credit of suffering for the cause of truth, had no small share in stirring up the there was, in fact, as much difficulty in reconciling the language of Scripture with the Ptolemaic as with the Copernican theory; and in 1615 he published a letter, addressed to the mother of the Grand Duke, in which the same arguments were stated at greater length, and enforced with quotations from the ancient fathers, and instances of the former practice of the Church. The publication of these letters gave great offence to the court of Rome; for, however favorably it might be disposed to the new doctrines, it could not submit to see the interpretation of the Scriptures wrested from the hands of the priesthood by a layman. Galileo having reason to apprehend that the doctrine would be formally condemned, proceeded to Rome for the purpose of endeavoring to avert, if possible, this consequence. He was brought before the tribunal of the Inquisition, charged with maintaining the doctrine of the motion of the earth and the immobility of the sun, teaching it to his pupils, and attempting to reconcile it to Scripture. In February, 1616, a congregation of cardinals, having considered the charges, decreed that Galileo should be enjoined to renounce the obnoxious doctrines, and to pledge himself, under the penalty of imprisonment, that he would neither teach, defend, or publish them in fuure. Galileo, says Sir David Brewster, '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 his writings, he was dismissed from the bar of the Inquisition.' Having disposed of the case of Galileo, the Congregation next proceeded to consider the doctrine itself; and, on the 5th of March of the same year, a formal decree was pronounced, declaring it to be false, and contrary to the Holy Scriptures; and in order that the heresy might spread no further to the prejudice of Catholic truth, they decreed that the work of Copernicus should be suspended until it should have been corrected; and that the book of one Foscarini, a Carmelite friar, should be altogether prohibited and condemned, together with all other works teaching the same doctrine. In this general prohibition, therefore, Galileo's letters to Castelli and the Grand Duchess were included, although they were not expressly named. Galileo remained for some time at Rome, doing his best, it would seem, notwithstanding his pledge, to frustrate these intentions. Nevertheless, he had an audience of the Pope, by whom he was very graciously received. The Pope assured him, 'that the Congregation were not disposed to receive upon light grounds any calumnies that might be propagated by his enemies, and that, so long as he occupied the papal chair, he might consider himself safe.' These assurances (Sir David Brewster remarks), 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.' To such a length was this imprudence carried, that the Tuscan minister, apprehensive of the consequences, represented the danger which Galileo was incurring to the Grand Duke, who, by a letter under his own hand, recalled him to Tuscany. In 1623, Cardinal Maffeo Barberini succeeded to the Papal Chair, under the title of Urban VIII. This personage having been an intimate friend of Galileo, the latter was induced to proceed to Rome, to congratulate him upon his accession. Here, says Sir D. Brewster, he met with a noble and generous reception : most marked description. He not only loaded Galileo with presents, and promised him a pension for his son Vincenzo, but wrote a letter to Ferdinand II., 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."' 'The kindness of his Holiness was of the The spirit in which Galileo met the forbearance of the Inquisition, and the favors of the Pope, is thus set forth : 'Although Galileo had made a narrow escape from the grasp of the Inquisition, yet which he experienced. he was never sufficiently sensible of the lenity 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. theory of the tides to the Archduke Leopold, In the year 1618, when he communicated his he alludes, in the most sarcastic terms, to the conduct of the Church. The same hostile tone, more or less, pervaded all his writings; and, while he labored to sharpen the edge of his satire, he endeavored to guard himself against its effecte by an affectation of the humblest deference to the decisions of theology.' It is justly remarked by Sir David Brewster, that whatever allowance may be made for the ardor of Galileo's temper, and however we may justify or even approve of his conduct up to this time, his visit to the Pope, in 1624, placed him in a new relation to the church, which demanded on his part a new and corresponding demeanor. The advances were made on his side-he had been received with courtesy and kindness -been loaded with favors, and had accepted pensions for himself and his son :— 'Thus honored 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, |