Produced by Bryan Ness, LN Yaddanapudi and the Online
Distributed Proofreading Team at http://www.pgdp.net (This
book was produced from scanned images of public domain
material from the Google Print project.)
THE
MARTYRS OF SCIENCE,
OR
THE LIVES
OF
GALILEO, TYCHO BRAHE, AND KEPLER.
BY
SIR DAVID BREWSTER, K.H. D.C.L.,
PRINCIPAL OF THE UNITED COLLEGE OF ST SALVATOR AND ST LEONARD,
ST ANDREWS; FELLOW OF THE ROYAL SOCIETY OF LONDON; VICE-PRESIDENT
OF THE ROYAL SOCIETY OF EDINBURGH; CORRESPONDING MEMBER
OF THE INSTITUTE OF FRANCE; AND MEMBER OF THE
ACADEMIES OF ST PETERSBURG, STOCKHOLM,
BERLIN, COPENHAGEN, GOTTINGEN,
PHILADELPHIA, &c. &c.
LONDON:
JOHN MURRAY, ALBEMARLE STREET.
1841.
G. S. TULLIS, PRINTER, CUPAR.
TO THE
RIGHT HON. FRANCIS LORD GRAY,
F.R.S., F.R.S.E.
MY LORD,
In submitting this volume to the public under your Lordship's auspices,
I avail myself of the opportunity thus afforded me of expressing the
deep sense which I entertain of the friendship and kindness with which
your Lordship has so long honoured me.
Although in these days, when Science constitutes the power and wealth of
nations, and encircles the domestic hearth with its most substantial
comforts, there is no risk of its votaries being either persecuted or
neglected, yet the countenance of those to whom Providence has given
rank and station will ever be one of the most powerful incitements to
scientific enterprise, as well as one of its most legitimate rewards.
Next to the satisfaction of cultivating Science, and thus laying up the
only earthly treasure which we can carry along with us into a better
state, is that of having encouraged and assisted others in the same
beneficent labours. That your Lordship may long continue to enjoy these
sources of happiness is the earnest prayer of,
MY LORD,
Your Lordship's
Most faithful and obedient servant,
DAVID BREWSTER.
ST LEONARDS, ST ANDREWS,
October 12, 1840.
CONTENTS.
LIFE OF GALILEO.
Page.
CHAPTER I. 1
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,
CHAPTER II. 20
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,
CHAPTER III. 42
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,
CHAPTER IV. 56
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 negotiation
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,
CHAPTER V. 72
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,
CHAPTER VI. 102
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,
* * * * *
LIFE OF TYCHO BRAHE.
CHAPTER I. 123
Tycho's Birth, Family, and Education--An Eclipse of the Sun turns
his attention to Astronomy--Studies Law at Leipsic--But pursues
Astronomy by stealth--His Uncle's Death--He returns to Copenhagen,
and resumes his Observations--Revisits Germany--Fights a Duel, and
loses his Nose--Visits Augsburg, and meets Hainzel--Who assists him
in making a large Quadrant--Revisits Denmark--And is warmly
received by the King--He settles at his Uncle's Castle of
Herritzvold--His Observatory and Laboratory--Discovers the new Star
in Cassiopeia--Account of this remarkable Body--Tycho's Marriage
with a Peasant Girl--Which irritates his Friends--His Lectures on
Astronomy--He visits the Prince of Hesse--Attends the Coronation of
the Emperor Rudolph at Ratisbon--He returns to Denmark,
CHAPTER II. 145
Frederick II. patronizes Tycho--And resolves to establish him in
Denmark--Grants him the Island of Huen for Life--And Builds the
splendid Observatory of Uraniburg--Description of the Island, and
of the Observatory--Account of its Astronomical Instruments--Tycho
begins his Observations--His Pupils--Tycho is made Canon of
Rothschild, and receives a large Pension--His Hospitality to his
Visitors--Ingratitude of Wittichius--Tycho sends an Assistant to
take the Latitude of Frauenburg and Konigsberg--Is visited by
Ulric, Duke of Mecklenburg--Change in Tycho's fortunes,
CHAPTER III. 160
Tycho's Labours do honour to his Country--Death of Frederick
II.--James VI. of Scotland visits Tycho at Uraniburg--Christian IV.
visits Tycho--The Duke of Brunswick's visit to Tycho--The Danish
Nobility, jealous of his fame, conspire against him--He is
compelled to quit Uraniburg--And to abandon his Studies--Cruelty of
the Minister Walchendorp--Tycho quits Denmark with his Family and
Instruments--Is hospitably received by Count Rantzau--Who
introduces him to the Emperor Rudolph--The Emperor invites him to
Prague--He gives him a Pension of 3000 Crowns--And the Castle of
Benach as a Residence and an Observatory--Kepler visits Tycho--Who
obtains for him the Appointment of Mathematician to Rudolph,
CHAPTER IV. 179
Tycho resumes his Astronomical Observations--Is attacked with a
Painful Disease--His Sufferings and Death in 1601--His Funeral--His
Temper--His Turn for Satire and Raillery--His Piety--Account of his
Astronomical Discoveries--His Love of Astrology and
Alchymy--Observations on the Character of the Alchymists--Tycho's
Elixir--His Fondness for the Marvellous--His Automata and Invisible
Bells--Account of the Idiot, called Lep, whom he kept as a
Prophet--History of Tycho's Instruments--His Great Brass Globe
preserved at Copenhagen--Present state of the Island of Huen,
* * * * *
LIFE OF JOHN KEPLER.
CHAPTER I. 203
Kepler's Birth in 1571--His Family--And early Education--The
Distresses and Poverty of his Family--He enters the Monastic School
of Maulbronn--And is admitted into the University of Tubingen,
where he distinguishes himself, and takes his Degree--He is
appointed Professor of Astronomy and Greek in 1594--His first
speculations on the Orbits of the Planets--Account of their
Progress and Failure--His "Cosmographical Mystery" published--He
Marries a Widow in 1597--Religious troubles at Gratz--He retires
from thence to Hungary--Visits Tycho at Prague in 1600--Returns to
Gratz, which he again quits for Prague--He is taken ill on the
road--Is appointed Tycho's Assistant in 1601--Succeeds Tycho as
Imperial Mathematician--His Work on the New Star of 1604--Singular
specimen of it,
CHAPTER II. 220
Kepler's Pecuniary Embarrassments--His Inquiries respecting the Law
of Refraction--His Supplement to Vitellio--His Researches on
Vision--His Treatise on Dioptrics--His Commentaries on Mars--He
discovers that the orbit of Mars is an Ellipse, with the Sun in one
focus--And extends this discovery to all the other Planets--He
establishes the two first laws of Physical Astronomy--His Family
Distresses--Death of his Wife--He is appointed Professor of
Mathematics at Linz--His Method of Choosing a Second Wife--Her
Character, as given by Himself--Origin of his Treatise on
Gauging--He goes to Ratisbon to give his Opinion to the Diet on the
change of Style--He refuses the Mathematical Chair at Bologna,
CHAPTER III. 237
Kepler's continued Embarrassments--Death of Mathias--Liberality of
Ferdinand--Kepler's "Harmonies of the World"--The Epitome of the
Copernican Astronomy--It is prohibited by the Inquisition--Sir
Henry Wotton, the British Ambassador, invites Kepler to
England--He declines the Invitation--Neglect of Genius by the
English Government--Trial of Kepler's Mother--Her final
Acquittal--And Death at the age of Seventy-five--The States of
Styria burn publicly Kepler's Calendar--He receives his Arrears of
Salary from Ferdinand--The Rudolphine Tables published in 1628--He
receives a Gold Chain from the Grand Duke of Tuscany--He is
Patronised by the Duke of Friedland--He removes to Sagan, in
Silesia--Is appointed Professor of Mathematics at Rostoch--Goes to
Ratisbon to receive his Arrears--His Death, Funeral, and
Epitaph--Monument Erected to his Memory in 1803--His Family--His
Posthumous Volume, entitled "The Dream, or Lunar Astronomy,"
CHAPTER IV. 252
Number of Kepler's published Works--His numerous Manuscripts in 22
folio volumes--Purchased by Hevelius, and afterwards by Hansch--Who
publishes Kepler's Life and Correspondence at the expense of
Charles VI.--The History of the rest of his Manuscripts, which are
deposited in the Library of the Academy of Sciences at St
Petersburg--General Character of Kepler--His Candour in
acknowledging his Errors--His Moral and Religious Character--His
Astrological Writings and Opinions considered--His Character as an
Astronomer and a Philosopher--The Splendour of his
Discoveries--Account of his Method of Investigating Truth,
LIFE OF GALILEO.
CHAPTER I.
_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
"The starry Galileo with his woes."[1]
[1] Childe Harold, canto iv. stanza liv.
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]
[2] Life of Galileo, Library of Useful Knowledge, p. 1.
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 Caesalpinus, 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.
[3] De Insidentibus in Fluido.
[4] Opere di Galileo. Milano, 1810, vol. iv. p. 248-257.
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 Moestlin, 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.
[5] Life of Galileo, in Library of Useful Knowledge, p. 9.
"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]
[6] Systema Cosmicum, Dial. ii. p. 121.
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.
[7] The authenticity of this work has been doubted. It was printed
at Rome, in 1656, from a MS. in the library of Somaschi, at Venice.
See Opere di Galileo, tom. vii. p. 427.
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."