although of noble descent. Their misfortunes, which had reduced them to
poverty, seem to have been aggravated by their own unhappy dispositions;
for his biographer informs us, that "his mother was treated with a
degree of barbarity by her husband and brother-in-law, that was hardly
exceeded by her own perverseness." It is fortunate, therefore, that
Kepler, in his childhood, was removed from the immediate society and
example of his parents, and educated at a public school at the expense
of the Duke of Wurtemberg. He early imbibed a taste for natural
philosophy, but had conceived a strong prejudice against astronomy, and
even a contempt for it, inspired, probably, by the arrogant and
ridiculous pretensions of the astrologers, who constituted the principal
astronomers of his country. A vacant post, however, of teacher of
astronomy, occurred when he was of a suitable age to fill it, and he was
compelled to take it by the authority of his tutors, though with many
protestations, on his part, wishing to be provided for in some other
more brilliant profession.
Happy is genius, when it lights on a profession entirely consonant to
its powers, where the objects successively presented to it are so
exactly suited to its nature, that it clings to them as the loadstone to
its kindred metal among piles of foreign ores. Nothing could have been
more congenial to the very mental constitution of Kepler, than the study
of astronomy,--a science where the most capacious understanding may find
scope in unison with the most fervid imagination.
Much as has been said against hypotheses in philosophy, it is
nevertheless a fact, that some of the greatest truths have been
discovered in the pursuit of hypotheses, in themselves entirely false;
truths, moreover, far more important than those assumed by the
hypotheses; as Columbus, in searching for a northwest passage to India,
discovered a new world. Thus Kepler groped his way through many false
and absurd suppositions, to some of the most sublime discoveries ever
made by man. The fundamental principle which guided him was not,
however, either false or absurd. It was, that God, who made the world,
had established, throughout all his works, fixed laws,--laws that are
often so definite as to be capable of expression in exact numerical
terms. In accordance with these views, he sought for numerical relations
in the disposition and arrangement of the planets, in respect to their
number, the times of their revolution, and their distances from one
another. Many, indeed, of the subordinate suppositions which he made,
were extremely fanciful; but he tried his own hypotheses by a rigorous
mathematical test, wherever he could apply it; and as soon as he
discovered that a supposition would not abide this test, he abandoned it
without the least hesitation, and adopted others, which he submitted to
the same severe trial, to share, perhaps, the same fate. "After many
failures," he says, "I was comforted by observing that the motions, in
every case, seemed to be connected with the distances; and that, when
there was a great gap between the orbits, there was the same between the
motions. And I reasoned that, if God had adapted motions to the orbits
in some relation to the distances, he had also arranged the distances
themselves in relation to something else."
In two years after he commenced the study of astronomy, he published a
book, called the '_Mysterium Cosmographicum_,' a name which implies an
explanation of the mysteries involved in the construction of the
universe. This work was full of the wildest speculations and most
extravagant hypotheses, the most remarkable of which was, that the
distances of the planets from the sun are regulated by the relations
which subsist between the five regular solids. It is well known to
geometers, that there are and can be only five _regular solids_. These
are, first, the _tetraedron_, a four-sided figure, all whose sides are
equal and similar triangles; secondly, the _cube_, contained by six
equal squares; thirdly, an _octaedron_, an eight-sided figure,
consisting of two four-sided pyramids joined at their bases; fourthly, a
_dodecaedron_, having twelve five-sided or pentagonal faces; and,
fifthly, an _icosaedron_, contained by twenty equal and similar
triangles. You will be much at a loss, I think, to imagine what relation
Kepler could trace between these strange figures and the distances of
the several planets from the sun. He thought he discovered a connexion
between those distances and the spaces which figures of this kind would
occupy, if interposed in certain ways between them. Thus, he says the
Earth is a circle, the measure of all; round it describe a dodecaedron,
and the circle including this will be the orbit of Mars. Round this
circle describe a tetraedron, and the circle including this will be the
orbit of Jupiter. Describe a cube round this, and the circle including
it will be the orbit of Saturn. Now, inscribe in the earth an
icosaedron, and the circle included in this will give the orbit of
Venus. In this inscribe an octaedron, and the circle included in this
will be the orbit of Mercury. On this supposed discovery Kepler exults
in the most enthusiastic expressions. "The intense pleasure I have
received from this discovery never can be told in words. I regretted no
more time wasted; I tired of no labor; I shunned no toil of reckoning;
days and nights I spent in calculations, until I could see whether this
opinion would agree with the orbits of Copernicus, or whether my joy was
to vanish into air. I willingly subjoin that sentiment of Archytas, as
given by Cicero; 'If I could mount up into heaven, and thoroughly
perceive the nature of the world and the beauty of the stars, that
admiration would be without a charm for me, unless I had some one like
you, reader, candid, attentive, and eager for knowledge, to whom to
describe it.' If you acknowledge this feeling, and are candid, you will
refrain from blame, such as, not without cause, I anticipate; but if,
leaving that to itself, you fear, lest these things be not ascertained,
and that I have shouted triumph before victory, at least approach these
pages, and learn the matter in consideration: you will not find, as just
now, new and unknown planets interposed; that boldness of mine is not
approved; but those old ones very little loosened, and so furnished by
the interposition (however absurd you may think it) of rectilinear
figures, that in future you may give a reason to the rustics, when they
ask for the hooks which keep the skies from falling."
When Tycho Brahe, who had then retired from his famous Uraniburg, and
was settled in Prague, met with this work of Kepler's, he immediately
recognised under this fantastic garb the lineaments of a great
astronomer. He needed such an unwearied and patient calculator as he
perceived Kepler to be, to aid him in his labors, in order that he might
devote himself more unreservedly to the taking of observations,--an
employment in which he delighted, and in which, as I mentioned, in
giving you a sketch of his history, he excelled all men of that and
preceding ages. Kepler, therefore, at the express invitation of Tycho,
went to Prague, and joined him in the capacity of assistant. Had Tycho
been of a nature less truly noble, he might have looked with contempt on
one who had made so few observations, and indulged so much in wild
speculation; or he might have been jealous of a rising genius, in which
he descried so many signs of future eminence as an astronomer; but,
superior to all the baser motives, he extends to the young aspirant the
hand of encouragement, in the following kind invitation: "Come not as a
stranger, but as a very welcome friend; come, and share in my
observations, with such instruments as I have with me."
Several years previous to this, Kepler, after one or two unsuccessful
trials, had found him a wife, from whom he expected a considerable
fortune; but in this he was disappointed; and so poor was he, that, when
on his journey to Prague, in company with his wife, being taken sick, he
was unable to defray the expenses of the journey, and was forced to cast
himself on the bounty of Tycho.
In the course of the following year, while absent from Prague, he
fancied that Tycho had injured him, and accordingly addressed to the
noble Dane a letter full of insults and reproaches. A mild reply from
Tycho opened the eyes of Kepler to his own ingratitude. His better
feelings soon returned, and he sent to his great patron this humble
apology: "Most noble Tycho! How shall I enumerate, or rightly estimate,
your benefits conferred on me! For two months you have liberally and
gratuitously maintained me, and my whole family; you have provided for
all my wishes; you have done me every possible kindness; you have
communicated to me every thing you hold most dear; no one, by word or
deed, has intentionally injured me in any thing; in short, not to your
own children, your wife, or yourself, have you shown more indulgence
than to me. This being so, as I am anxious to put upon record, I cannot
reflect, without consternation, that I should have been so given up by
God to my own intemperance, as to shut my eyes on all these benefits;
that, instead of modest and respectful gratitude, I should indulge for
three weeks in continual moroseness towards all your family, and in
headlong passion and the utmost insolence towards yourself, who possess
so many claims on my veneration, from your noble family, your
extraordinary learning, and distinguished reputation. Whatever I have
said or written against the person, the fame, the honor, and the
learning, of your Excellency; or whatever, in any other way, I have
injuriously spoken or written, (if they admit no other more favorable
interpretation,) as to my grief I have spoken and written many things,
and more than I can remember; all and every thing I recant, and freely
and honestly declare and profess to be groundless, false, and incapable
of proof." This was ample satisfaction to the generous Tycho.
"To err is human: to forgive, divine."
On Kepler's return to Prague, he was presented to the Emperor by Tycho,
and honored with the title of Imperial Mathematician. This was in 1601,
when he was thirty years of age. Tycho died shortly after, and Kepler
succeeded him as principal mathematician to the Emperor; but his salary
was badly paid, and he suffered much from pecuniary embarrassments.
Although he held the astrologers, or those who told fortunes by the
stars, in great contempt, yet he entertained notions of his own, on the
same subject, quite as extravagant, and practised the art of casting
nativities, to eke out a support for his family.
When Galileo began to observe with his telescope, and announced, in
rapid succession, his wonderful discoveries, Kepler entered into them
with his characteristic enthusiasm, although they subverted many of his
favorite hypotheses. But such was his love of truth, that he was among
the first to congratulate Galileo, and a most engaging correspondence
was carried on between these master-spirits.
The first planet, which occupied the particular attention of Kepler, was
Mars, the long and assiduous study of whose motions conducted him at
length to the discovery of those great principles called 'Kepler's
Laws.' Rarely do we meet with so remarkable a union of a vivid fancy
with a profound intellect. The hasty and extravagant suggestions of the
former were submitted to the most laborious calculations, some of which,
that were of great length, he repeated seventy times. This exuberance of
fancy frequently appears in his style of writing, which occasionally
assumes a tone ludicrously figurative. He seems constantly to
contemplate Mars as a valiant hero, who had hitherto proved invincible,
and who would often elude his own efforts to conquer him, "While thus
triumphing over Mars, and preparing for him, as for one altogether
vanquished, tabular prisons, and equated, eccentric fetters, it is
buzzed here and there, that the victory is vain, and that the war is
raging anew as violently as before. For the enemy, left at home a
despised captive, has burst all the chains of the equation, and broken
forth of the prisons of the tables. Skirmishes routed my forces of
physical causes, and, shaking off the yoke, regained their liberty. And
now, there was little to prevent the fugitive enemy from effecting a
junction with his own rebellious supporters, and reducing me to despair,
had I not suddenly sent into the field a reserve of new physical
reasonings, on the rout and dispersion of the veterans, and diligently
followed, without allowing the slightest respite, in the direction in
which he had broken out."
But he pursued this warfare with the planet until he gained a full
conquest, by the discovery of the first two of his laws, namely, that
_he revolves in an elliptical orbit_, and that _his radius vector passes
over equal spaces in equal times_.
Domestic troubles, however, involved him in the deepest affliction.
Poverty, the loss of a promising and favorite son, the death of his
wife, after a long illness;--these were some of the misfortunes that
clustered around him. Although his first marriage had been an unhappy
one, it was not consonant to his genius to surrender any thing with only
a single trial. Accordingly, it was not long before he endeavored to
repair his loss by a second alliance. He commissioned a number of his
friends to look out for him, and he soon obtained a tabular list of
eleven ladies, among whom his affections wavered. The progress of his
courtship is thus narrated in the interesting 'Life' contained in the
'Library of Useful Knowledge.' It furnishes so fine a specimen of his
eccentricities, that I cannot deny myself the pleasure of transcribing
the passage for your perusal. It is taken from an account which Kepler
himself gave in a letter to a friend.
"The first on the list was a widow, an intimate friend of his first wife
and who, on many accounts, appeared a most eligible match. At first, she
seemed favorably inclined to the proposal: it is certain that she took
time to consider it, but at last she very quietly excused herself.
Finding her afterwards less agreeable in person than he had anticipated,
he considered it a fortunate escape, mentioning, among other objections,
that she had two marriageable daughters, whom, by the way, he had got on
his list for examination. He was much troubled to reconcile his
astrology with the fact of his having taken so much pains about a
negotiation not destined to succeed. He examined the case
professionally. 'Have the stars,' says he, 'exercised any influence
here? For, just about this time, the direction of the mid-heaven is in
hot opposition to Mars, and the passage of Saturn through the ascending
point of the zodiac, in the scheme of my nativity, will happen again
next November and December. But, if these are the causes, how do they
act? Is that explanation the true one, which I have elsewhere given? For
I can never think of handing over to the stars the office of deities, to
produce effects. Let us, therefore, suppose it accounted for by the
stars, that at this season I am violent in my temper and affections, in
rashness of belief, in a show of pitiful tender-heartedness, in catching
at reputation by new and paradoxical notions, and the singularity of my
actions; in busily inquiring into, and weighing, and discussing, various
reasons; in the uneasiness of my mind, with respect to my choice. I
thank God, that that did not happen which might have happened; that this
marriage did not take place. Now for the others.' Of these, one was too
old; another, in bad health; another, too proud of her birth and
quarterings; a fourth had learned nothing but showy accomplishments, not
at all suitable to the kind of life she would have to lead with him.
Another grew impatient, and married a more decided admirer while he was
hesitating. 'The mischief,' says he, 'in all these attachments was,
that, whilst I was delaying, comparing, and balancing, conflicting
reasons, every day saw me inflamed with a new passion.' By the time he
reached No. 8, of his list, he found his match in this respect. 'Fortune
has avenged herself at length on my doubtful inclinations. At first, she
was quite complying, and her friends also. Presently, whether she did or
did not consent, not only I, but she herself, did not know. After the
lapse of a few days, came a renewed promise, which, however, had to be
confirmed a third time: and, four days after that, she again repented
her conformation, and begged to be excused from it. Upon this, I gave
her up, and this time all my counsellors were of one opinion.' This was
the longest courtship in the list, having lasted three whole months;
and, quite disheartened by its bad success, Kepler's next attempt was of
a more timid complexion. His advances to No. 9 were made by confiding to
her the whole story of his recent disappointment, prudently determining
to be guided in his behavior, by observing whether the treatment he
experienced met with a proper degree of sympathy. Apparently, the
experiment did not succeed; and, when almost reduced to despair, Kepler
betook himself to the advice of a friend, who had for some time past
complained that she was not consulted in this difficult negotiation.
When she produced No. 10, and the first visit was paid, the report upon
her was as follows: 'She has, undoubtedly, a good fortune, is of good
family, and of economical habits: but her physiognomy is most horribly
ugly; she would be stared at in the streets, not to mention the striking
disproportion in our figures. I am lank, lean, and spare; she is short
and thick. In a family notorious for fatness, she is considered
superfluously fat.' The only objection to No. 11 seems to have been, her
excessive youth; and when this treaty was broken off, on that account,
Kepler turned his back upon all his advisers, and chose for himself one
who had figured as No. 5, in his list, to whom he professes to have felt
attached throughout, but from whom the representations of his friends
had hitherto detained him, probably on account of her humble station."
Having thus settled his domestic affairs, Kepler now betook himself,
with his usual industry, to his astronomical studies, and brought before
the world the most celebrated of his publications, entitled 'Harmonics.'
In the fifth book of this work he announced his _Third Law_,--that the
squares of the periodical times of the planets are as the cubes of the
distances. Kepler's rapture on detecting it was unbounded. "What," says
he, "I prophesied two-and-twenty years ago, as soon as I discovered the
five solids among the heavenly orbits; what I firmly believed long
before I had seen Ptolemy's Harmonics; what I had promised my friends in
the title of this book, which I named before I was sure of my discovery;
what, sixteen years ago, I urged as a thing to be sought; that for which
I joined Tycho Brahe, for which I settled in Prague, for which I have
devoted the best part of my life to astronomical contemplations;--at
length I have brought to light, and have recognised its truth beyond my
most sanguine expectations. It is now eighteen months since I got the
first glimpse of light, three months since the dawn, very few days since
the unveiled sun, most admirable to gaze on, burst out upon me. Nothing
holds me: I will indulge in my sacred fury; I will triumph over mankind
by the honest confession, that I have stolen the golden vases of the
Egyptians to build up a tabernacle for my God, far from the confines of
Egypt. If you forgive me, I rejoice: if you are angry, I can bear it;
the die is cast, the book is written, to be read either now or by
posterity,--I care not which. I may well wait a century for a reader, as
God has waited six thousand years for an observer." In accordance with
the notion he entertained respecting the "music of the spheres," he made
Saturn and Jupiter take the bass, Mars the tenor, the Earth and Venus
the counter, and Mercury the treble.
"The misery in which Kepler lived," says Sir David Brewster, in his
'Life of Newton,' "forms a painful contrast with the services which he
performed for science. The pension on which he subsisted was always in
arrears; and though the three emperors, whose reigns he adorned,
directed their ministers to be more punctual in its payment, the
disobedience of their commands was a source of continual vexation to
Kepler. When he retired to Silesia, to spend the remainder of his days,
his pecuniary difficulties became still more harassing. Necessity at
length compelled him to apply personally for the arrears which were due;
and he accordingly set out, in 1630, when nearly sixty years of age, for
Ratisbon; but, in consequence of the great fatigue which so long a
journey on horseback produced, he was seized with a fever, which put an
end to his life."
Professor Whewell (in his interesting work on Astronomy and General
Physics considered with reference to Natural Theology) expresses the
opinion that Kepler, notwithstanding his constitutional oddities, was a
man of strong and lively piety. His 'Commentaries on the Motions of
Mars' he opens with the following passage: "I beseech my reader, that,
not unmindful of the Divine goodness bestowed on man, he do with me
praise and celebrate the wisdom and greatness of the Creator, which I
open to him from a more inward explication of the form of the world,
from a searching of causes, from a detection of the errors of vision;
and that thus, not only in the firmness and stability of the earth, he
perceive with gratitude the preservation of all living things in Nature
as the gift of God, but also that in its motion, so recondite, so
admirable, he acknowledge the wisdom of the Creator. But him who is too
dull to receive this science, or too weak to believe the Copernican
system without harm to his piety,--him, I say, I advise that, leaving
the school of astronomy, and condemning, if he please, any doctrines of
the philosophers, he follow his own path, and desist from this wandering
through the universe; and, lifting up his natural eyes, with which he
alone can see, pour himself out in his own heart, in praise of God the
Creator; being certain that he gives no less worship to God than the
astronomer, to whom God has given to see more clearly with his inward
eye, and who, for what he has himself discovered, both can and will
glorify God."
In a Life of Kepler, very recently published in his native country,
founded on manuscripts of his which have lately been brought to light,
there are given numerous other examples of a similar devotional spirit.
Kepler thus concludes his Harmonics: "I give Thee thanks, Lord and
Creator, that Thou has given me joy through Thy creation; for I have
been ravished with the work of Thy hands. I have revealed unto mankind
the glory of Thy works, as far as my limited spirit could conceive their
infinitude. Should I have brought forward any thing that is unworthy of
Thee, or should I have sought my own fame, be graciously pleased to
forgive me."
As Galileo experienced the most bitter persecutions from the Church of
Rome, so Kepler met with much violent opposition and calumny from the
Protestant clergy of his own country, particularly for adopting, in an
almanac which, as astronomer royal, he annually published, the reformed
calendar, as given by the Pope of Rome. His opinions respecting
religious liberty, also, appear to have been greatly in advance of the
times in which he lived. In answer to certain calumnies with which he
was assailed, for his boldness in reasoning from the light of Nature, he
uttered these memorable words: "The day will soon break, when pious
simplicity will be ashamed of its blind superstition; when men will
recognise truth in the book of Nature as well as in the Holy Scriptures,
and rejoice in the two revelations."
LETTER XXV.
COMETS.
----"Fancy now no more
Wantons on fickle pinions through the skies,
But, fixed in aim, and conscious of her power,
Sublime from cause to cause exults to rise,
Creation's blended stores arranging as she flies."--_Beattie._