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ent brief but interesting Memoirs; for ness and moderation in speaking of the though their services to science are dis- characters and conduct of those to whom tinctly set forth, and on the whole accu- he was opposed. rately appreciated, they are not dwelt upon Galileo Galilei, born at Pisa in 1564. at such length, or with so much detail, as was descended from a patrician, though to interfere with the popular character of decayed family, some of whose members the work. He does not profess to have had had filled high civic offices in Florence. 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 fof 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 lures 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; il abounds Euclid was followed by that of Archimedes; with traits of good feeling and generous and after some ineffectual attempts on the sympathy; and, what may be regarded as part of his father to recall him to his proof inportance in a popular work, it repre- fessional studies, he was allowed to follow sents science and its pursuits under an at- the bent of his genius. But Vincenzo, tractive and dignified aspect.
being burdened with a numerous family, The life of Galileo, whom Sir David was unable to maintain his son at Pisa; Brewster places at the head of his mariyrs, he applied for a bursary, and was disaphas been given by his numerous biogra- pointed ; and Galileo was compelled to phers with great minuteness of detail. The leave the university without taking his 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 forth with conceived a friendmer of whom was one of his pupils, and ship for the young author, and procured revered his inemory 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 hinilish; but the want was ably supplied by the self conspicuous for the freedom and boldelaborate thuugh 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 siy, has afforded our author considerable strong party in the university. In 1592, he facilities in preparing the present Memoir. was appointed by the republic of Venice, The recent historical work of Libri* has an again on the recommendation of Ubaldi, to account of Galileo which is very valuable the professorship of mathematics at Padua, from its fulness and research, and the care with a salary of 180 florins. At that time, 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- his engagement had expired, he was re
elected for another period of six years, * Histoire des Sciences Mathématiques en Italie. with an increased salary of 320 forins; Tom. iv. 1841.
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 sion of a telescope which magnified three was frequently obliged to adjourn to the 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, foun
out the construction of the vining the construction, and improving the telescope. The instrument excited intense instrument. He affirms that he had nerer 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 forins. 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, with Duke 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 es. ment 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, Dew 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 pres
Being thus placed in a situation of inde- ent day, they cease to be regarded with wcppendence,and in possession of uninterrupted /der, could not fail, on their first announceseisure, 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 plıysical 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 with ness, and incorruptible essence of the heavena greater number of brilliant discoveries. Ty bodies; of which he was not slow to take ad
Galileo'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 nebulæ 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 posproperty of causing distant objects to ap- sibly exist,) was the satellites of Jupiter. pear nearer to the observer ; that on reflect. Four small plavets revolving about a cening on the means by which this effect could tral body, and presenting so palpable and be produced, he found, after a night's con- striking an analogy to the primary planets sideration, the explanation in the principle terolving 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 Jaying 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) Taws 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 insually 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 kuowledge 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 (pubbaps, 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 ihen 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 have existing 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 announce
The 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 embitiered. 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 harinto 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, hvad 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 objec
The circumstances which entiile Galileo tions which his opponents drew from certain to be regarded as a martyr of science, are texts of Scripture, Galileo, in a letter to his the persecutions he sustained on account friend and pupil Castelli, endeavored to of his assertion of the earth's motion ; his prove that the expressions employed in the trial, condemnation, and imprisonment, by sacred writings were not intended to have the Inquisition; and his constrained ab- reference to astronomical systems; and that juration, in his old age, of the Copernican there was, in fact, as much difficulty in redoctrine, which it had been the principal conciling the language of Scripture with business of his life to establish. This epi- the Ptolemaic as with the Copernican thesode in his history has been represented in ory; and in 1615 he published a letter, advery different colors by his biographers ; dressed to the mother of the Grand Duke, some ascribing his persecution to the in which the same arguments were stated jealousy with which the Romish Church at greater length, and enforced with quotahas always been disposed to regard the tions from the ancient fathers, and instanpropagation of physical knowledge; while ces of the former practice of the Church. others have considered that it was provoked, The publication of these letters gave great if not altogether compelled, by his own offence to the court of Rome; for, however imprudent conduct; which left the heads favorably it might be disposed to the new of the Church no alternative but to reduce doctrines, it could not submit to see the him to silence, or abandon their pretensions interpretation of the Scriptures wrested to spiritual authority. Sir David Brewster from the hands of the priesthood by a layhas treated this subject with fairness and man. Galileo having reason to apprehend moderation. He is no apologist of the that the doctrine would be formally conInquisition ; yet, on perusing his narrative, demned, proceeded to Rome for the purwe cannot fail to see that its conduct, in pose of endeavoring to avert, if possible, this particular case, was not without cir- this consequence. He was brought before cumstances of palliation; and that Gali- the tribunal of the Inquisition, charged leo himself like many others who have with maintaining the doctrine of the motion had the credit of suffering for the cause of of the earth and the immobility of the sun, truth, had no small share in stirring up the teaching it to his pupils, and attempting to
reconcile it to Scripture. In February, s In 1623, Cardinal Maffeo Barberini suc1616, a congregation of cardinals, having ceeded to the Papal Chair, under the title considered the charges, decreed that Galileo of Urban VIII. This personage having should be enjoined to renounce the obnox- been an intimate friend of Galileo, the latter ious doctrines, and to pledge himself, under was induced to proceed to Rome, to congratthe penalty of imprisonment, that he would ulate him upon his accession.
Here, says neither teach, defend, or publish them in fu- Sir D. Brewster, he met with a noble and ure. Galileo, says Sir David Brewster, 'did generous reception :not hesitate to yield to this injunction. On the day following, the 26th of February, he most marked description. He not only loaded
"The kindness of his Holiness was of the appeared before Cardinal Bellarmine to re- Galileo with presents, and promised him a nounce his heretical opinions; and, having pension for his son Vincenzo, but wrote a letter declared that he abandoned the doctrine of io Ferdinand II., who had just succeeded Costhe earth's motion and would neither de- mo as Grand Duke of Tuscany, recommendfend nor teach it, in his conversation or ing Galileo to his particular patronage:-“ For his writings, he was dismissed from the bar we find in him," says he, "not only literary of the Inquisition.'
distinction, but the love of piety ; and he is Having disposed of the case of Galileo, strong in those qualities by which pontifical the Congregation next proceeded to consid good will is easily obtained?", er the doctrine itself; and, on the 5th of The spirit in which Galileo met the forMarch of the same year, a formal decree bearance of the Inquisition, and the fawas pronounced, declaring it to be false, vors of the Pope, is thus set forth : and contrary to the Holy Scriptures; and in order that the heresy might spread no
Although Galileo had made a narrow further to the prejudice of Catholic truth, he was never suficiently sensible of the lenity
from the grasp of the Inquisition, yet they decreed that the work of Copernicus which he experienced. When he left Rome, should be suspended until it should have in 1616, under the solemn pledge of never been corrected; and that the book of one again teaching the obnoxious doctrine, it was Foscarini, a Carmelite friar, should be al- with a hostility against the Church, suppresstogether prohibited and condemned, to-ed, but deeply cherished; and his resolution to gether with all other works teaching the propagate the heresy seems to have been cosame doctrine. In this general prohibi-eval with the yow by which he renounced it.
In the year 1618, when he communicated his tion, therefore, Galileo's letters to Castelli
theory of the tides to the Archduke Leopold, and the Grand Duchess were included, al- he alludes, in the most sarcastic terms, to the though they were not expressly named. conduct of the Church. The same hostile Galileo remained for some time at Rome, tone, more or less, pervaded all his writings; doing his best, it would seem, notwithstand- and, while he labored to sharpen the edge of ing his pledge, to frustrate these intentions. his satire, he endeavored to guard himself Nevertheless, he had an audience of the against its effecie by an affectation of the hum
blest deference to the decisions of theology.' Pope, by whom he was very graciously received. The Pope assured him, 'that the
It is justly remarked by Sir David BrewCongregation were not disposed to receive ster, that whatever allowance may be made upon light grounds any calumnies that for the ardor of Galileo's temper, and howmight be propagated by his enemies, and ever we may justify or even approve of his that, so long as he occupied the papal chair, conduct up to this time, his visit to the he might consider himself safe.' These Pope, in 1024, placed him in a new relation assurances (Sir David Brewster remarks), to the church, which demanded on his part * were no doubt founded on the belief that a new and corresponding demeanor. The Galileo would adhere to his pledges; but advances were made on his side—he had so bold and inconsiderate was he in the ex- been received with courtesy and kindness pression of his opinions, that, even in -been loaded with favors, and had acceptRome, he was continually engaged in con- ed pensions for himself and his son :troversial discussions.' To such a length was this imprudence carried, that the Tus "Thus honored by the head of the church, can minister, apprehensive of the conse
and befriended by its dignitaries, Galileo must
have felt himself secure against the indigniquences, represented the danger which
ties of its lesser functionaries, and in the posGalileo was incurring to the Grand Duke, session of the fullest license to prosecute his who, by a letter under his own hand, re- researches and publish his discoveries, providcalled hiin to Tuscany.
ed he avoided that dogma of the church which,