the modern discoverer of the rational and true system of astronomy,
as now universally received, under the title of his name, was born at
Thorn, a city of Royal Prussia, 19th February, 1473. Having learnt the
Latin and Greek Languages in his father’s house, he was sent to Cracow,
to be instructed in philosophy and physic, where he was honoured with
the degree of doctor; showing a greater predilection for mathematics
than medicine. His uncle by his mother’s side was a bishop, who gave
him a canonry upon his return from Italy, whither he had gone to
study astronomy, under Dominic Maria, at Bologna, and had afterwards
taught mathematics with success at Rome. In the repose and solitude of
an ecclesiastical life, he bent his chief attention to the study of
astronomy. Dissatisfied with the system of Ptolemy, which had prevailed
fourteen centuries, he laboured to form a juster one. What led him to
discover the mistakes of Ptolemy was his observations on the motions
of Venus; he is said to have derived his first notion on this subject
from various passages in the classics, which mention the opinions of
Pythagoras and his followers, as, indeed, he himself acknowledges in
his address to Pope Paul III. He established the rotation of the earth
round its axis, and its motion round the sun; but to explain certain
irregularities in the motion of the planets, he retained the epicicles
and eccentrics of Ptolemy. His work was first printed at Nuremberg, in
1543, a short time before his death.
The doctrines of Copernicus were not at first generally adopted. The
most eminent professors in Europe adhered to the old opinions.
Among the astronomers of this period, the Landgrave of Hesse deserves
particular praise, who erected a magnificent observatory at the top
of the Castle of Cassel, and made many observations himself, in
conjunction with Christopher Rothman and Justus Burge, concerning the
place of the sun, of the planets, and of the stars.
But the person who enriched astronomy with the greatest number of facts
of any modern who had yet appeared, was Tycho Brahe, a Dane of noble
extraction, born in 1546, designed by his parents for the study of the
law; but attracted by an eclipse of the sun in 1560, at Copenhagen,
whither he had been sent to learn philosophy, he was struck with
astonishment in observing that the phenomenon happened at the very
moment it had been predicted.
He admired the art of predicting eclipses, and wished to acquire it. At
first, for want of proper instruments, he fell into several mistakes,
which, however, he afterwards corrected. Having early perceived his
future improvements must depend on instruments, he caused some to be
constructed larger than usual, and thus rendered more exact. On the
11th November, 1572, he perceived a new star in Cassiopeia, which
continued without changing its place till spring 1574, equal in
splendour to Jupiter or Venus. It last it changed colours and entirely
disappeared. Nothing similar to this had been observed since the days
of Hipparchus.
Tycho, in imitation of that illustrious astronomer, conceived a design
of forming a catalogue of the stars. To promote his views, the King of
Denmark ordered a castle to be built in Hueun, an island between Seonia
and Zealand, which Tycho called Uranibourg, “the city of heaven,” and
where he placed the finest collection of instruments that had ever
yet appeared; most of them invented or else improved by himself. He
composed a catalogue of seven hundred and seventy-seven stars, with
greater exactness than had ever been done before; and constructed
tables for finding the place of the most remarkable stars at any
given time. He was the first who determined the effect of refraction,
whereby we see the sun or any star above the horizon, before it is
so in reality; as we see the bottom of a vessel when filled with
water, standing at a distance, which we could not see when empty. He
made several other improvements and important discoveries, which he
published in a work entitled “Progymnasmata.” The labours of Tycho
attracted the attention of Europe; the learned went to consult him, and
the noble to see him. James VI. of Scotland, when he went to espouse
the sister of Frederic, King of Denmark, paid Tycho a visit, with all
his retinue, and wrote some Latin verses in his praise.
But these honours were of short continuance. After the death of his
protector, King Frederic, the pension assigned him was withdrawn, and
he was compelled to exile himself from his native country. Having hired
a ship, he transported his furniture, books, and instruments to a small
place in Hamburgh, in 1597. The Emperor Rodolphus invited him into his
dominions, settled a large pension upon him, gave him a castle near
Prague, to prosecute his discoveries, and appointed him Longomatus,
a native of Jutland, and the celebrated Kepler, to assist him. But
Tycho was not happy in his new situation; he died 14th October, 1601,
repeating several times, “I have not lived in vain.”
Kepler was one of the greatest philosophers that ever lived, and ought
to be considered as the discoverer of the _true_ system of the world.
He was born in Germany, at Wiel, near Wirtemberg, 27th December,
1571. He early imbibed the principles of Copernicus. After the death
of Tycho, he was employed to finish the tables which he had begun to
compose from his observations. Kepler took twenty years to finish them.
He dedicated them to the emperor, under the title of the “Rodolphine
Tables.”
Kepler united optics with astronomy, and thus made the most important
discoveries. He was the first who discovered that the _planets move
not in a circle, but in an ellipse_; and that altogether they move
sometimes faster and sometimes slower, yet that they describe equal
areas in equal times; that is, that the spaces through which they
move in different parts of their orbit, are of equal times, though
of unequal length; yet when two straight lines are drawn from the
extremity of either space to the centre of the sun, they form triangles
which include equal areas. He likewise demonstrated that the squares of
the periodical times of the revolution of the planets round the sun,
are in proportion to the cubes of their distance from him; a theorem
of the greatest use in astronomical calculations: for having the
periodical times of two planets given, and if the distance of one of
them be known, by the rule of proportion, the distance of the other can
be ascertained.
Kepler is said to have used logarithms in framing his “Rodolphine
Tables.” This great man died in poverty, 15th November, 1631, at
Ratisbon, whither he had gone to solicit the arrears of his pension,
which had been very ill paid: he left nothing to his wife and children
but the remembrance of his virtues.
Contemporary with Kepler was Galileo, born at Pisa, in Italy, in 1564;
illustrious for his improvements in mechanics, for his application
of the effects of gravity, and for the invention, or at least, the
improvement of telescopes.
The use of spectacles, or reading glasses (convex for long-sighted; and
concave for short-sighted persons,) had been invented by one Spina, a
monk at Pisa, in 1290; or, as some say, by our countryman Roger Bacon.
The use of telescopes or glasses for viewing objects at a distance,
was invented by Zachary Janssen, a spectacle-maker, at Middleburg, or
rather, as it is said, from the accidental discovery of a child. The
honour of this invention is also claimed by others. It is certain that
Galileo first improved them so as to answer astronomical purposes.
He also first made use of the single pendulum for measuring time in
making his observations; to which he was led, by considering one day
the vibrations of a lamp suspended from the vaulted roof of a church.
He likewise discovered the gravity of the atmosphere from the rising of
water in a pump, by the action of a piston, which led the way to the
invention of the barometer, by his scholar Toricelli.
The use of telescopes opened, in a manner, a new world to Galileo.
He observed with astonishment the increased magnitude and splendour
of the planets and their satellites, formerly invisible: which
afforded additional proofs of the veracity of the Copernican system,
particularly the satellites of Jupiter, and the phasis of Venus. He
discovered an innumerable multitude of fixed stars, which the naked eye
could not discern, and what greatly excited his wonder, without the
least increase in their size or brightness.
About the same time, John Napier, of Merchiston, in Scotland, invented
what are called “Logarithms,” first published at Edinburgh in 1614,
afterwards improved by Mr. Briggs, Professor of Geometry, at Oxford,
in which, by a very ingenious contrivance, addition is made to answer
for multiplication, and subtraction for division; an invention of the
greatest utility in astronomical calculations.
Galileo was not afflicted with poverty, but with persecution. At
seventy years of age he was called before the Holy Inquisition, for
supporting opinions contrary to Scripture,--and was obliged, on the
11th of June, 1633, formally to abjure them, to avoid being burnt as
a heretic. The system of Copernicus had yet gained but few converts;
and the bulk of professions and learned men in Europe, attached to
the philosophy of Aristotle, supported the old doctrine. Galileo was
condemned to prison, and confined to the small city of Arcem, with its
territory, where he consoled himself by the study of astronomy. He
contrived a method of discovering the longitude by the satellites of
Jupiter, which, however, has not been productive of all the advantages
he expected. He died in prison, or rather in exile, in 1642.
Although there were a great number of astronomers contemporary with
Kepler and Galileo, none made any conspicuous figure. John Bayer,
of Augsburg, introduced the Jewish method of marking the stars with
letters of the Greek and Latin alphabets; this the Jews use because
their law does not permit the use of figures, the produce of fancy.
In 1732, astronomers were very attentive to observe the transit of
Venus over the disc of the sun, which Kepler had predicted, as a
confirmation of the system of Copernicus. Mercury was observed by
Gassendi in France, and some others; but the transit of Venus did not
then take place for their inspection.
The transit of Venus was first seen by Jeremiah Horrox, of Hoole,
an obscure village, fifteen miles north of Liverpool, on the 24th of
November, 1639, and at the same time by his friend, William Crabtree,
at Manchester. Horrox was born in 1619, and died in 1641, in the
twenty-third year of his age. He wrote an account of his observations,
which were published after his death, under the title of “Venus in Sole
visa,” by Hevelius.
The Copernican system was first publicly defended in England, by Dr.
Wilkins, in 1660; in France, by Gassendi, the son of a peasant in
Provence, who published many valuable works on Philosophy. He was born
in 1592, and died in 1655. He was violently opposed by Morin, a famous
astrologer.
Descartes, descended from a noble family, the son of a counsellor of
Brittany, in France, born at Haye, in Tourraine, 31st of March, 1596,
early distinguished himself by his knowledge in algebra and geometry.
He attacked and overturned the philosophy of Aristotle, in his own
country. He attempted to establish certain principles, which, though
founded in theory, he took for granted, by which he accounted for all
appearances. Like Mochus and Democritus, he imagined all space to be
filled with corpuscules, or atoms, in continual agitation, and denied
the possibility of a vacuum. He explained everything by supposing
vortices, or motions round a centre, according to the opinions of
Democritus, and thus discovered the centrifugal force in the circular
motion of the planets. But the system of Descartes not being founded on
facts or experiments, did not subsist long: although at first it had
many followers. His astronomical opinions were much the same with those
of Copernicus.
Although the lively notions of Descartes led him into error, yet his
exalted views greatly contributed to the improvement of science. Men
were led to observation and experiments, in order to overturn his
system, and astronomy was cultivated by persons of ability; viz.,
Bouillard, at Paris; Ward, at Oxford, 1653; and by Helvelius, at
Dantzic, 1643, who constructed a fine observatory, and collected a
great many facts by his long assiduous observation, for fifty years,
during which he made many discoveries concerning the planets, fixed
stars, and particularly comets. Colbert, in the name of Louis XIV.,
sent him a sum of money and a pension. Hevelius published a catalogue
of fixed stars, entitled, “Firmamentum Sobieskianum,” dedicated to
John Sobieski, King of Poland, at that time justly famous for having
raised the siege of Vienna, when attacked by the Turks, 1683. In honour
of whom Helvelius formed a new constellation between Antinonus and
Serpenterius, called _Sobieski’s Shield_.
But the most distinguished astronomer of that time was Christian
Huygens, son to the secretary of the Prince of Orange, born at the
Hague, 14th of April, 1629, and educated at Leyden, under Schooten, the
commentator on Descartes,--famous for the application of pendulums to
clocks and springs to watches, for the improvement of telescopes and
microscopes, and for the great discoveries he made, in consequence of
these improvements in astronomy.
The establishment of academies, or societies, at this time, contributed
greatly to the advancement of science.
The Royal Society, in London, was begun in 1659, but did not assume a
regular form till 1662. Its transactions were first published in 1665.
The Academy of Sciences, at Paris, was founded in 1686, by Louis XIV.,
who invited to it Rœmer, from Denmark, Huygens and Cassini from Italy.
Cassini was born at Perinaldo, in the county of Nice, on the 8th of
June, 1625, and was appointed first professor in the Royal Observatory
at Paris, where he prosecuted his discoveries till his death, in 1712,
and was succeeded by his son. He was assisted by Picard, Auzoul, and La
Hire.
By the direction of the Academy of Sciences at Paris, a voyage was
undertaken by Riecher and Meurisse, at the king’s expense, to the
island of Caienne, in South America, almost under the equator, in 1672,
to ascertain several philosophical facts;--the refraction of light,
the parallax of Mars, and of the Sun, the distance of the tropics, the
variation in the motion of the pendulum, &c.
The parallax of the sun is the angle under which an observer at the
sun would see the earth: this Cassini fixed at 9½ seconds, and the
angle under which we see the sun, at 16 minutes and 6 seconds, or 966
seconds; hence he concluded that these semi-diameters, are as 9½ to
966, or as 10 to 1932. So that, according to Cassini, the semi-diameter
of the earth is one hundred times less than that of the sun; and
consequently the sun is a million times larger than the earth.
The parallax of the sun has since, from the transit of Venus, 6th of
June, 1761, and 3rd of June, 1769, been discovered to be but about 8
seconds, consequently his comparative bulk to that of the earth, and
his distance from it, to be proportionably greater. The method of
finding the distance of the earth from the sun, and consequently of the
other planets, was first proposed by Dr. Halley, who had never seen,
and was morally certain he would never see, this appearance.
Meurisse died during the voyage. Riecher returned in 1676. His answer
to the parallax of Mars was not satisfactory. Cassini calculated it at
15 seconds.
The distance of the tropics was found to be 46 degrees, 57 minutes, 4
seconds. The chief advantage resulting from the voyage was ascertaining
the vibration of the pendulum. In 1669, Placard remarked that clocks
went slower in summer than in winter, owing to, as since ascertained,
that it is the property of heat to dilate bodies, which consequently
lengthens the pendulum; that cold produces an opposite effect. Riecher
found that the pendulum made forty-eight vibrations less at Caienne
than at Paris; that it went two minutes and twenty seconds a day
slower; hence, to adjust, he was obliged to shorten the pendulum.
The same fact was confirmed by Halley, while at St. Helena, 1676. But
an additional reason for this variation is presumed to exist, from the
machinery being further removed from the central axis of the earth; the
gravitating principle is presumed to be diminished at the equator more
than it is when nearer the poles.
About this time the French Jesuit missionaries, having got admission
into China, contributed greatly to the improvement of their astronomy.
Father Schaal, one of their number, on account of his merit, and
particularly for his skill in astronomy, was so highly honoured by
the court of China, that the emperor, upon his death-bed, made him
preceptor to his son and successor. Schaal reformed the Kalendar, a
matter of great importance to that country. It was further improved
by Verbiest, who succeeded Schaal, about 1670. The most eminent
astronomers in England during this period were Flamstead, Halley, and
Hook.
Sir Isaac Newton was born at Woolstrope, in Lincoln, December 25, 1642;
after due preparation he was admitted in the University of Cambridge.
The rapidity of his progress in mathematical knowledge was truly
astonishing. At the age of twenty-four, he had laid the foundation of
the most important mathematical discoveries. He is the first who gave
a rational and complete account of the laws which regulate planetary
motion, on the principles of attraction and gravitation. Newton was as
remarkable for a modest diffidence of his own abilities, as for the
superiority of his genius. In 1704, he published his “Optics;” in 1711,
his “Fluxions;” and in 1728, his “Chronology.” He received in his life
time the honour due to his singular merit. In 1703, he was elected
President of the Royal Society. In 1705, he received the honour of
knighthood by Queen Anne.--He was twice member of parliament. In 1669,
he was made master of the mint, which, with the presidency of the Royal
Society, he held till his death, in 1726. He was buried in Westminster
Abbey, where there is an appropriate monument to his memory.
The system of Newton had an eminent supporter and able annotator in
the very eminent Scottish professor, Colin Mac Laurin, who was born
in the month of February, 1698. In 1719, he travelled to London,
where he was introduced to the illustrious Newton, whose notice and
friendship he obtained, and ever after reckoned as the greatest honour
and happiness of his life. In 1734, Dr. Berkeley, Bishop of Cloyne,
published his treatise, called “The Analyst,” in which he attempted
to charge mathematicians with infidelity in matters of religion. This
work was the occasion of Mac Laurin’s elaborate “Treatise on Fluxions,”
published at Edinburgh, in 1742, which is reckoned the most ample
treatise on that branch of novel mathematics which has yet appeared. So
very eminent was Mac Laurin’s skill in mathematics, and the principles
of anatomical science, and he possessed such excellent instruments for
these purposes, that a new theory never appeared, nor did anything
transpire in the scientific world, which was uncommon, but his friends
constantly resorted to him for explanation and experiment, and their
laudable curiosity was sure to be satisfactorily gratified.
One of the greatest names in the modern history of astronomical
discovery is that of the late Sir William Herschel; and, much to his
praise, he was self-instructed in the science in which he earned his
high reputation. Herschel was born at Hanover, in 1736, and was the
son of a musician in humble circumstances. Brought up to his father’s
profession, at the age of fourteen he was placed in the band of the
Hanoverian Guards. A detachment of this regiment having been ordered
to England in the year 1757, he and his father accompanied it; but
the latter returned to Germany in a few months, and left his son to
try his fortune in London. For a long time he had many difficulties
to contend with, and he passed several years principally in giving
lessons in music in the different towns in the North of England. At
last, in 1765, through the interest of a gentleman to whom his merits
had become known, he obtained the situation of organist at Halifax; and
next year, having gone to fulfil a short engagement at Bath, he gave
so much satisfaction by his performances, that he was appointed to the
same office in the Octagon Chapel of that city, upon which he went to
reside there. The place which he now held was of some value; and from
the opportunities which he enjoyed of adding to its emoluments, by
engagements at the rooms and private concerts, as well as by taking
pupils, he had had the prospect of deriving a good income from his
profession, if he had made that his only or his chief object.
During his residence at Bath, although greatly occupied with
professional engagements, the time he devoted to his mathematical
studies was surprising. Often, we are told, after a fatiguing day’s
work of fourteen or sixteen hours among his pupils, he would, on
returning home at night, repair for relaxation to what many would
deem these severer exercises. In this manner, in the course of time,
he attained a competent knowledge of geometry, and found himself in a
condition to proceed to the study of the different branches of physical
science which depend upon the mathematics. Among the first of the
latter that attracted his attention, were the kindred departments of
astronomy and optics. Having applied himself to these sciences, he
became desirous of beholding with his own eyes those wonders of the
heavens of which he had read so much, and for that purpose he borrowed
from an acquaintance a two-feet Gregorian telescope. This instrument
interested him so greatly, that he determined to procure one of his
own, and commissioned a friend in London to purchase one for him, of a
somewhat larger size. But he found the price was beyond what he could
afford. To make up for this disappointment, he resolved to construct a
telescope for himself; and after encountering innumerable difficulties
in the progress of his task, he at last succeeded, in the year 1774, in
completing a five-feet Newtonian reflector. This was the commencement
of a long and brilliant course of triumphs in the same walk of art, and
also in that of astronomical discovery. Herschel now became so much
more ardently attached to his philosophical pursuits, that, regardless
of the sacrifice of emolument he was making, he begun gradually to
limit his professional engagements, and the number of his pupils.
Meanwhile he continued to employ his leisure in the fabrication of
still more powerful instruments than the one he had first constructed;
and in no long time he produced telescopes of seven, ten, and even
twenty feet focal distance. In fashioning the mirrors for these
instruments, his perseverance was indefatigable. For his seven-feet
reflector, we have been informed that he actually finished and made
trial of no fewer than two hundred mirrors before he found one that
satisfied him. When he sat down to prepare a mirror, his practice
was to work at it for twelve or fourteen hours, without quitting his
occupation for a moment. He would not even take his hand from what he
was about, to help himself to food; and the little he ate on such
occasions was put into his mouth by his sister. He gave the mirror a
proper shape, more by a certain natural tact than by rule; and when his
hand was once in, as the phrase is, he was afraid that the perfection
of the finish might be impaired by the least intermission of his
labours.