按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
Nantes； Queen Elizabeth had defeated the Invincible Armada； and
William the Silent had achieved the independence of Holland。
Such were some of the lights and some of the enterprises of that
great age； when the profoundest questions pertaining to philosophy；
religion； law； and government were discussed with the enthusiasm
and freshness of a revolutionary age； when men felt the inspiration
of a new life； and looked back on the Middle Ages with disgust and
hatred； as a period which enslaved the human soul。 But what
peculiarly marked that period was the commencement of those
marvellous discoveries in science which have enriched our times and
added to the material blessings of the new civilization。 Tycho
Brahe； Copernicus； Galileo； Kepler； and Bacon inaugurated the era
which led to progressive improvements in the physical condition of
society； and to those scientific marvels which have followed in
such quick succession and produced such astonishing changes that we
are fain to boast that we have entered upon the most fortunate and
triumphant epoch in our world's history。
Many men might be taken as the representatives of this new era of
science and material inventions； but I select Galileo Galilei as
one of the most interesting in his life； opinions； and conflicts。
Galileo was born at Pisa； in the year 1564； the year that Calvin
and Michael Angelo died； four years after the birth of Bacon； in
the sixth year of the reign of Elizabeth； and the fourth of Charles
IX。； about the time when the Huguenot persecution was at its
height； and the Spanish monarchy was in its most prosperous state；
under Philip II。 His parents were of a noble but impoverished
Florentine family； and his father； who was a man of some learning；
a writer on the science of music；gave him the best education he
could afford。 Like so many of the most illustrious men； he early
gave promise of rare abilities。 It was while he was a student in
the university of his native city that his attention was arrested
by the vibrations of a lamp suspended from the ceiling of the
cathedral； and before he had quitted the church； while the choir
was chanting mediaeval anthems； he had compared those vibrations
with his own pulse； which after repeated experiments； ended in the
construction of the first pendulum；applied not as it was by
Huygens to the measurement of time； but to medical science； to
enable physicians to ascertain the rate of the pulse。 But the
pendulum was soon brought into the service of the clockmakers； and
ultimately to the determination of the form of the earth； by its
minute irregularities in diverse latitudes； and finally to the
measurement of differences of longitude by its connection with
electricity and the recording of astronomical observations。 Thus
it was that the swinging of a cathedral lamp； before the eye of a
man of genius； has done nearly as much as the telescope itself to
advance science； to say nothing of its practical uses in common
life。
Galileo had been destined by his father to the profession of
medicine； and was ignorant of mathematics。 He amused his leisure
hours with painting and music； and in order to study the principles
of drawing he found it necessary to acquire some knowledge of
geometry； much to the annoyance of his father； who did not like to
see his mind diverted from the prescriptions of Hippocrates and
Galen。 The certain truths of geometry burst upon him like a
revelation； and after mastering Euclid he turned to Archimedes with
equal enthusiasm。 Mathematics now absorbed his mind； and the
father was obliged to yield to the bent of his genius； which seemed
to disdain the regular professions by which social position was
most surely effected。 He wrote about this time an essay on the
Hydrostatic Balance； which introduced him to Guido Ubaldo； a famous
mathematician； who induced him to investigate the subject of the
centre of gravity in solid bodies。 His treatise on this subject
secured an introduction to the Grand Duke of Tuscany； who perceived
his merits； and by whom he was appointed a lecturer on mathematics
at Pisa； but on the small salary of sixty crowns a year。
This was in 1589； when he was twenty…five； an enthusiastic young
man； full of hope and animal spirits； the charm of every circle for
his intelligence； vivacity； and wit； but bold and sarcastic；
contemptuous of ancient dogmas； defiant of authority； and therefore
no favorite with Jesuit priests and Dominican professors。 It is
said that he was a handsome man； with bright golden locks； such as
painters in that age loved to perpetuate upon the canvas； hilarious
and cheerful； fond of good cheer； yet a close student； obnoxious
only to learned dunces and narrow pedants and treadmill professors
and zealous priests；all of whom sought to molest him； yet to whom
he was either indifferent or sarcastic； holding them and their
formulas up to ridicule。 He now directed his inquiries to the
mechanical doctrines of Aristotle； to whose authority the schools
had long bowed down； and whom he too regarded as one of the great
intellectual giants of the world； yet not to be credited without
sufficient reasons。 Before the 〃Novum Organum〃 was written； he
sought； as Bacon himself pointed out； the way to arrive at truth；
a foundation to stand upon； a principle tested by experience；
which； when established by experiment； would serve for sure
deductions。
Now one of the principles assumed by Aristotle； and which had never
been disputed； was； that if different weights of the same material
were let fall from the same height； the heavier would reach the
ground sooner than the lighter； and in proportion to the difference
of weight。 This assumption Galileo denied； and asserted that； with
the exception of a small difference owing to the resistance of the
air； both would fall to the ground in the same space of time。 To
prove his position by actual experiment； he repaired to the leaning
tower of Pisa； and demonstrated that he was right and Aristotle was
wrong。 The Aristotelians would not believe the evidence of their
own senses； and ascribed the effect to some unknown cause。 To such
a degree were men enslaved by authority。 This provoked Galileo；
and led him to attack authority with still greater vehemence；
adding mockery to sarcasm； which again exasperated his opponents；
and doubtless laid the foundation of that personal hostility which
afterwards pursued him to the prison of the Inquisition。 This
blended arrogance and asperity in a young man was offensive to the
whole university； yet natural to one who had overturned one of the
favorite axioms of the greatest master of thought the world had
seen for nearly two thousand years； and the scorn and opposition
with which his discovery was received increased his rancor； so that
he； in his turn； did not render justice to the learned men arrayed
against him； who were not necessarily dull or obstinate because
they would not at once give up the opinions in which they were
educated； and which the learned world still accepted。 Nor did they
oppose and hate him for his new opinions； so much as from dislike
of his personal arrogance and bitter sarcasms。
At last his enemies made it too hot for him at Pisa。 He resigned
his chair （1591）； but only to accept a higher position at Padua； on
a salary of one hundred and eighty florins；not； however； adequate
to his support； so that he was obliged to take pupils in
mathematics。 To show the comparative estimate of that age of
science； the fact may be mentioned that the professor of scholastic
philosophy in the same university was paid fourteen hundred
florins。 This was in 1592； and the next year Galileo invented the
thermometer； still an imperfect instrument； since air was not
perfectly excluded。 At this period his reputation seems to have
been established as a brilliant lecturer rather than as a great
discoverer； or even as a great mathematician； for he was
immeasurably behind Kepler； his contemporary； in the power of
making abstruse calculations and numerical combinations。 In this
respect Kepler was inferior only to Copernicus； Newton； and Laplace
in our times； or Hipparchus and Ptolemy among the ancients； and it
is to him that we owe the discovery of those great laws of
planetary motion from which there is no appeal； and which have
never been rivalled in importance except those made by Newton
himself；laws which connect the mean distance of the planets from
the sun with the times of their revolutions； laws which show that
the orbits of planets are elliptical； not circular； and that the
areas described by lines drawn from the moving planet to the sun
are proportionable to the times employed in the motion。 What an
infinity of calculation； in the infancy of sciencebefore the
invention of logarithms；was necessary to arrive at these truths！
What fertility of invention was displayed in all his hypot