science with success, was Thales, born at Miletus, in Asia Minor, six
hundred and forty one years before Christ; he explained the causes of
eclipses, and predicted one. He also taught that the earth was round,
and divided into five zones; he discovered the solstices and equinoxes,
and likewise divided the year into three hundred and sixty-five
days. He had travelled into Egypt in search of knowledge, where he
ascertained the height of one of the pyramids, from its shade. He
looked upon water as the principle of all things. From him the sect
called the Ionic had their origin.
Anaximander, his pupil, followed him, and supported the opinions of his
great master; he was born before Christ six hundred and ten years; he
invented maps and dials, and is said to have constructed a sphere. His
ideas of the planets were, however, erroneous.
Anaximenes was a scholar of Anaximander, and born five hundred and
fifty-four years before Christ. He taught that air was the origin of
all things, and many erroneous notions; among others, that the earth
was a plane, and the heavens a solid concave sphere, with the stars
affixed to it like nails.
Anaxagoras of Clazomene, the pupil of, and successor to, Anaximenes,
born before Christ five hundred and sixty years. The doctrines he
supported are a strange association of important truths, mixed with
the most gross absurdities. He taught that the world was made by a
being of infinite power; that mind was the origin of motion; that the
upper regions, which he called ether, were filled with fire, that the
rapid revolution of this ether had raised large masses of stone from
the earth, which, being inflamed, formed the stars, which were kept
in their places, and prevented from falling by the velocity of their
motion.
His ideas of the solar orb were extremely erroneous; alleging,
according to different authors, various uncertain positions respecting
the materials of which that planet is composed: one says, _he_ said
it was a vast mass of fire; another states _his_ opinion, that it
was red-hot iron; and a third, that it was of stone. He taught that
the comets are an assemblage of planets; that winds are produced in
consequence of highly rarified air; that thunder and lightning are a
collision of clouds; earthquakes, by subterraneous air forcing its
passage upwards; that the moon is inhabited, &c.
This philosopher removed his school from Miletus to Athens, which was
thenceforth the grand seat of all learning. He had taught there for
thirty years, when he was prosecuted for his philosophical opinions,
particularly for his just ideas relative to the Deity, and condemned to
death. When sentence was pronounced, he said:--“It is long since Nature
condemned me to that.” However, according to the laws of Athens, he was
permitted an appeal to the people, in which his scholar, the immortal
Pericles, saved his life by his eloquence. His sentence of death
was changed into banishment. Whilst in prison he determined exactly
the proportion of the circumference of the circle to its diameter,
denominated “squaring the circle.” He died at Lampsacus. Archelaus, his
scholar, was the preceptor of the divine Socrates.
Pythagoras was another scholar of Thales. The place of his nativity is
uncertain; but having settled in the island of Samos, he is generally
reckoned of that place. He travelled in search of knowledge through
Phœnicia, Chaldea, Egypt, and India; however, meeting with little
encouragement on his return to Samos, he passed over to Italy, in the
time of Tarquin the Proud, and opened a school at Croto, a city in the
Gulf of Tarentum, where he had a number of students, and gained much
reputation. His pupils were obliged to listen in silence for at least
two years; if talkative, longer; sometimes, for five years, before
they were permitted to ask him any questions; for which time they were
_mathematicoi_, because they were set to study geometry, dialling,
music, and other high sciences, called by the Greeks _mathemata_. But
the name of _mathematici_ was commonly applied to those who cultivated
the stellary science, and who predicted the fortunes of men, by
observing the stars under which they were born.
This luminary of science first assumed the appellation of
_philosopher_; before him, those whose pursuits have now that title,
were called sages or wise men; he was the founder of the sect called
the Italic. He was so much honoured whilst living, and his memory
honoured when dead, by the Romans, that they attributed to him the
learning of Numa, who lived much earlier. About the year of the city
411, the Delphian oracle having directed the Romans to erect statues to
the bravest and wisest of the Greeks, they conferred that honour upon
Alcibiades and Pythagoras.
He taught publicly that the earth is the centre of the universe; but
to his scholars he gave his real opinions; similar to those afterwards
adopted by Copernicus, that the earth and all the planets moved round
the sun, as their co-centre, and which doctrine he is presumed to have
derived from either the Chaldeans or Indians. He thought that the earth
is round, and everywhere inhabited. Hence, he admitted that we might
have antipodes, which name is said to have been invented by Plato.
Pythagoras was distinguished for his skill in music, which he first
reduced to certain firm principles, and likewise for his discoveries
in geometry. He first proved, that in a right-angled triangle, the
square of the hypothenuse, or side subtending the right angle, is
equal to the two other sides; also that of all plain figures having
equal circumference, the circle is largest; and of all solids having
equal surfaces, the sphere is the largest. Pythagoras likewise taught
that all things were made of fire. That the Deity animated the
universe, as the soul does the body; which doctrine, with that of
the metempsychosis, or transmigration, he likewise taught; and which
thoughts were adopted by Plato, and are most beautifully expressed by
Virgil; that the sun, the moon, the planets, and fixed stars, are all
actuated by some divinity, and move each in a transparent solid sphere
in the order following:--next to the Earth, the Moon, then Mercury,
Venus, the Sun, Mars, Jupiter, Saturn; the sphere of the fixed stars
last of all; that those move with a sound inconceivably beautiful,
which ears cannot comprehend. Those eight spheres he imagined to be
analogous to the eight notes in music.
Empedocles, the chief scholar of Pythagoras, entertained the same
sentiments with his teacher, concerning astronomy. He is said to have
thrown himself into the crater of Mount Etna, to make himself pass for
a god; or, perhaps, which may approach nearer the truth, because he
could not discover the cause of the eruption: or else in his endeavours
to discover the cause. One of his iron sandals being thrown up by the
volcano, revealed the mode in which he had perished.
Philolaus, also a scholar of Pythagoras, first taught publicly the
diurnal motion of the earth upon its axis, and its annual motion round
the sun; which first suggested to Copernicus the idea of that system
which he established.
Meteon, born at Leuconæ, a village near Athens, first introduced into
Europe the Lunar Cycle, consisting of nineteen solar years, or nineteen
lunar years, and seven intercalary months. It had been first adopted by
the Chaldeans. Meteon published it at the Olympic games, where it was
received with so great applause that it was then universally adopted
through the Grecian States, and their colonies, and got the name of the
Cycle, or Golden Number, to denote its excellence, which name it still
retains.
It was also called the Great Year; which name was likewise applied to
various spaces of time by different authors; by Virgil, to the solar
year, to distinguish it from the monthly revolution of the moon; by
Cicero and others, to the revolution of six hundred years, or three
thousand six hundred years; called also several ages, when all the
stars shall come to the same position, with respect to one another,
as they were in at a certain time before; called likewise _Annus
Mundanus_, or _Vertens_.
The lunar cycle begun four hundred and thirty-two years before the
commencement of our era, and according to it, the Greek calendars,
which determined the celebration of their annual feasts, &c. were
adjusted. Meteon is said to have derived his knowledge of this subject
from Chaldea.
The opinions of the subsequently registered astronomer, Xonophanes,
founder of the Eleatic school, are so truly monstrous, that after
the light which had appeared, he must have travelled with his eyes
shut; or else the rage for novelty alike affected the scientific of
Greece, as it did their _literati_; choosing to travel a long way
for new thoughts, when they might have found much better at hand.
Xonophanes, among other whimsical opinions, maintained that the stars
were extinguished every morning, and illuminated every evening; that
the sun is an inflamed cloud; that eclipses happen by the extinction
of the sun, which is afterwards lighted up; that the moon is ten times
larger than the earth; that there are many suns and moons to illumine
different climates.
The Eleatic school was chiefly famous for the study of logic, or the
art of ratiocination, first invented by Zeno. Those of this sect paid
but little attention to science, or the study of Nature. Philosophy
was anciently divided into three parts, natural, moral, and the art of
reasoning. Xonophanes was succeeded by Parmenides, his scholar, who,
in addition to his master’s absurdities, taught that the earth was
habitable in only the two temperate zones; that the earth was suspended
in the middle of the universe, in a fluid lighter than air; that all
bodies left to themselves light on its surface. This bore a slight
resemblance to the Newtonian doctrine of attraction.
Democritus, of Abdera, a scholar of Leucippus, who flourished four
hundred and fifty-six years before Christ, was the first publisher
of the Atomic Cosmogony, invented by Mochus, the Phœnician, said to
have been received by his master Leucippus. Both admitted plurality
of worlds. Democritus was the first who taught that the milky way is
occasioned by the confused light of an infinite number of stars; which
doctrine is still maintained by the best informed of philosophers. He
also extended that idea to comets; the number of which Seneca says the
Greek philosophers did not know; and that Democritus suspected there
were more planets than we could see. This was also the opinion of many
others, the truth of which has been verified in the discoveries of
Pallas, Juno, Vesta, and the _Georgium Sidus_.
Democritus is considered as the parent of experimental philosophy; the
greatest part of his time was devoted to it; and he is said to have
made many discoveries. He, like Meteon, and Newton, maintained the
absurd idea of the existence of a vacuum, which was denied by Thales
and Descartes. Democritus also maintained that the sea was constantly
diminishing. He declared that he would prefer the discovery of one of
the causes of the works of Nature, to the possession of the Persian
monarchy. Often laughing at the follies of mankind, he was thought by
the vulgar to be out of his mind; but Hippocrates, being sent to cure
him, soon found him to be the wisest man of the age; and Seneca reckons
him the most acute and ingenious of the ancients, on account of his
many useful inventions; particularly his ingenious making of artificial
emeralds, tinging them of any colour; of softening ivory, dissolving
stones, &c.
Although the chief attention of Plato and Aristotle was directed to
other grand objects, yet they much contributed to the improvement of
astronomy. Notwithstanding the most famous in this respect was Eudoxus,
the scholar of Plato, who was famous for his skill in astrology,
natural and judicial, or the art of foretelling future events by
the relative situations of the stars, of their various influences,
an art which prevailed for many ages among the ancients, and is yet
assiduously cultivated by the modern Arabians and other orientals,
although in a great measure exploded in European nations. By the
former or which divisions in this science are foretold the changes of
seasons, rain, wind, thunder, cold, heat, famine, diseases, &c., from a
knowledge of the causes that are believed to act upon the earth and its
atmosphere; whilst the latter foretold the characters, fortunes, &c.,
of men, from the stellary disposition at the moment of their respective
nativities.
The philosopher, Eudoxus, spent much of his time on the top of a high
mountain, to observe the motion of the stars. He regulated the Greek
year as Cæsar did the Roman. Had the ancient Grecian astronomers been
equally attached to experiment with Democritus, they might have arrived
at more certain conclusions; but they were content with speculative
theory, and spoke rather from conjecture than observation; whence both
Strabio and Polybius treated as fabulous the since recognised assertion
of Pythius, a famous navigator to the north, who had sailed to a
country supposed to be Iceland, where he said the sun, in the middle of
summer, never set.
The most important improvements in astronomy were made in the school
of Alexandria, founded by Ptolemy Philadelphus; and which seminary
flourished for nine hundred and twenty-three years, till the invasion
of the Saracen army, under the command of Amrou. Those astronomers
were chiefly Greeks, or of Grecian extraction--the most learned men
being invited here by the liberality of the Ptolemies. The first
who distinguished themselves were Timocarus and Aristillus, prior to
the foundation of the library, which was founded three hundred years
before Christ. Those two men endeavoured to determine the places of the
different stars, and thus to trace the course of the planets. The next
and most eminent man was Aristarchus, about two hundred and sixty-four
years before Christ; who taught, that the sun was about nineteen times
further from the earth than the moon (which is not the twentieth part
of its real distance), although the philosophers of the Pythagorean
school did not consider it above three times, and perhaps only one
and a half further distant. Aristarchus also taught, that the moon
was fifty-six diameters of our earth from this globe, which opinion
comes near to the truth: he believed it to be scarcely one-third of
its real size. He was widely erroneous in his conception of the sun’s
dimensions. He also, in conformity to the doctrines of Pythagorus and
Philolaus, supposed the sun to be placed in the centre, and that the
earth moved round it; on which account he was accused of impiety, as
disturbing the repose of the Vesta and the Lares. This opinion was not,
however, retained by his successors in the Alexandrian school. Contrary
to the doctrine of the Greek philosophers, he taught that the stars
were at different distances, and that the orbit of the earth round the
sun was an insensible point, in consequence of the immense distance
of the stars. The only work of Aristarchus which remains, is on the
magnitude and distance of the sun and moon.
Very nearly contemporary with Aristarchus was Euclid, the celebrated
geometrician of Alexandria; Manetho, an astrologer and historian; and
Aratus and Cleanthus, disciples of Zeno, the stoic philosopher; all
of whom contributed to the enlargement of astronomical knowledge; but
particularly the two first named.
Eratosthenes, born at Cyrene, succeeded Aristarchus, being invited by
Ptolemy Euergetes. This professor is said to be the inventor of the
Armillary sphere, an instrument or machine composed of moveable sides,
representing the equator, the two colures, with the meridian; all of
which turned round on an axis directed to the two poles of the world,
each of which circles were anciently called armilla, and the whole
machine, astrolabus. All instruments which could be contrived for
the promotion of this science, were furnished at the public expense,
and placed within the observatory of Alexandria. Assisted by these
instruments, Eratosthenes first undertook to measure the obliquity of
the ecliptics, or rather the double of that obliquity, that is, the
distance from the tropics, which he made to be about 47 degrees; the
obliquity, or half of this distance, 23½ degrees. This grand attempt
was to ascertain the exact distance of a degree of the meridian, and
thus to determine the circumference of the earth; which he accomplished
with wonderful exactness, considering the period at which he lived;
and he performed this by the same method since adopted by the moderns
who have succeeded him. He is also said to have discovered the true
distance of the sun from the earth.
The great Archimedes lived contemporary with Eratosthenes, that
eminent geometrician of Syracuse, whose inventive genius in mechanics
had constructed engines which protracted the fall of that capital,
with its Island Sicily, to the almost omnipotent power of Rome for a
considerable period.
The most illustrious astronomer which had as yet appeared at Alexandria
was Hipparchus, who flourished between one hundred and sixty and one
hundred and twenty-five years before Christ. He first brought this
science into a tangible elementary form, rendering it systematic. He
discovered, or was the first who observed the difference between the
autumnal and the vernal equinox; the former being seven days longer
than the latter, which proceeds from the eccentricity of the earth’s
orbit, first discovered from observing the inequality of the solar
motion. He framed tables for what is called equation of time, or to
ascertain the difference between the shade on a well constructed dial
and a perfectly regulated clock. He made great progress in explaining
the motions and phases of the moon; however, he was not so successful
with respect to the planets.
His greatest work was his ascertaining the number of the stars, marking
their distances, and arriving at the means by which their precise
places on the hemisphere of Alexandria could be known. He marked one
thousand six hundred stars, in seventy-two signs, into which the
heavens were divided. Pliny says this was a labour which must have been
difficult even to a god. The appearance of a new star induced him to
set about and accomplish this work, which he did in a catalogue for the
benefit of future observers.
Hipparchus does not mention comets, whence it has been conjectured he
had never seen any; it has also been suggested, that he considered
them with meteors, which are not objects of astronomical observation.
He divided the heavens into forty-nine constellations, viz., twelve in
the ecliptic, twenty-one in the north, and sixteen in the south. To one
of these he gave the name of Berenice’s Hair, in honour of the wife of
Ptolemy Soter, who had consecrated her hair, which was very beautiful,
to Venus Urania, if her husband should return from a war in Asia
victorious; it being hung up in the temple of the goddess, soon after
disappeared, and is said to have been carried off by the gods.
Hipparchus likewise constructed a sphere, or celestial globe, on which
all the stars visible at Alexandria were depicted; and thought to have
been similar to the Faranese globe at Rome, still extant. In his
observations on the stars, he discovered that, when viewed from the
same spot, their distance always appeared the same from each other;
but he discovered the distance of the moon to be different in various
parts of the heavens; for instance, in the horizon and zenith. This
he conceived to be owing to the extent of the globe; he, therefore,
contrived a method of reducing appearances of this kind, to what they
would be if viewed from the centre of the earth, which is called a
parallax; and the discovery of it was of the greatest importance to
astronomy. He took this idea from observing that a tree, in the middle
of a plain, appeared in different parts of the horizon, when viewed
from different situations; so does a star appear in the various points
of the heavens, when viewed in different parts of the globe. Hipparchus
was the first who connected geography with astronomy, and this fixed
both the sciences on certain principles.
After the overthrow of the Roman empire, the first encourager of
learning was Charles the Great, or Charlemagne; but little could be
done in his time; after his death the former ignorance prevailed.
Beda, or Bede, from his piety and modesty termed _venerabilis_, and
his scholar, Alcinius, both Englishmen, greatly excelled in general
literature; among other qualifications they were eminent in the
astronomy of the preceding period. The first step towards the revival
of knowledge, or the translation of the Astronomical Elements of
Alfergan, the Arab, by order of Frederick II., chosen Emperor of
Germany in 1212. About the same time Alphonso X., King of Castile,
assembled from all parts the most famous astronomers, who at his
desire, composed what are called the Alphonsine Tables, founded on the
hypothesis of Ptolemy.
About the same period John Sacrobosco, of Holywood, a native of
Halifax, in Yorkshire, who was educated at Oxford, and taught
mathematics and philosophy at Paris, made an abridgment of the
amalgamist of Ptolemy, and of the commentaries of the Arabs, which was
long famous as an elementary book under the title of “De Sphira Mundi.”
He died at Paris, in the year 1235. In the same year, Roger Bacon, an
English Franciscan friar, made astonishing discoveries in science for
the time he lived. He perceived the error in the Kalendar of Julius
Cæsar, and proposed a plan, for the correction of it, to Pope Clement
IV. in 1267. He is presumed from his writings to have known the use
of optical glasses, and the composition and effects of gunpowder.
He believed in planetary influence on men’s fortunes, and the
transmutation of metals. On account of his vast knowledge in astronomy,
mathematics, and chemistry, he was called Doctor _Mirabilis_; but, for
the same reason, he was suspected of magic. Under this pretext, whilst
at Paris, he was put in prison by order of the Pope’s legate; and
after a long and severe confinement, he was at last, by the interest
of several noble persons, liberated, returned to England, and died at
Oxford in 1292, in the seventy-eighth year of his age.
In the fifteenth century two events happened which changed the face of
the sciences; the invention of printing, about 1440, and the taking
of Constantinople by the Turks in 1453. The learned men of that city
having escaped from the cruelty of the victors, fled into Italy, and
again introduced the taste for classical literature; which was greatly
promoted by the munificence of the Emperor Frederick III., Pope
Nicholas V., and particularly of Cosmo de Medici, who justly merited
the title of Father of his Country, and Patron of the Muses.
The restoration of astronomy began in Germany. The first who
distinguished himself, was George Purbach, born at Purbach, on the
confines of Austria and Bavaria, in 1423, who was cut off in the
flower of his age--only thirty-eight years old. He was succeeded by
a scholar more skilful than himself, John Muller, born at Konigsberg,
in 1436, who taught mathematics and astronomy with great reputation at
Vienna. In February, 1471, appeared a comet, on which he published his
observations. Being called to Rome by Pope Sextus IV., to assist in
correcting the Kalender, he was cut off by the plague, in 1476. Bernard
Waltherus, a rich citizen of Nuremberg, his friend and associate,
succeeded him, who is said to have first made use of clocks in his
astronomical observations, in 1484, and to have been the first of the
moderns who perceived the effects of the refraction of light.
Fracastorius, born at Verona, in 1483, was a celebrated astronomer, and
an eminent poet and good philosopher; he made considerable discoveries
in this science, and with all his abilities may be considered as the
precursor of the celebrated Copernicus.