[ Pobierz całość w formacie PDF ]

tempered woman; indeed, the ill-assorted union came to an abrupt end through the desertion
of the wife by her husband when their eldest son John, the hero of our present sketch, was
file:///D|/Great Astronomers (Ball, R. S.)/greatastronomers2.htm (40 of 156) [03.04.2007 19:19:46]
Great Astronomers
eighteen years old. The childhood of this lad, destined for such fame, was still further
embittered by the circumstance that when he was four years old he had a severe attack of
small-pox. Not only was his eyesight permanently injured, but even his constitution appears to
have been much weakened by this terrible malady.
It seems, however, that the bodily infirmities of young John Kepler were the immediate cause
of his attention being directed to the pursuit of knowledge. Had the boy been fitted like other
boys for ordinary manual work, there can be hardly any doubt that to manual work his life
must have been devoted. But, though his body was feeble, he soon gave indications of the
possession of considerable mental power. It was accordingly thought that a suitable sphere for
his talents might be found in the Church which, in those days, was almost the only profession
that afforded an opening for an intellectual career. We thus find that by the time John Kepler
was seventeen years old he had attained a sufficient standard of knowledge to entitle him to
admission on the foundation of the University at Tubingen.
In the course of his studies at this institution he seems to have divided his attention equally
between astronomy and divinity. It not unfrequently happens that when a man has attained
considerable proficiency in two branches of knowledge he is not able to see very clearly in
which of the two pursuits his true vocation lies. His friends and onlookers are often able to
judge more wisely than he himself can do as to which Of the two lines it would be better for
him to pursue. This incapacity for perceiving the path in which greatness awaited him, existed
in the case of Kepler. Personally, he inclined to enter the ministry, in which a promising career
seemed open to him. He yielded, however, to friends, who evidently knew him better than he
knew himself, and accepted in 1594, the important Professorship of astronomy which had
been offered to him in the University of Gratz.
It is difficult for us in these modern days to realise the somewhat extraordinary duties which
were expected from an astronomical professor in the sixteenth century. He was, of course,
required to employ his knowledge of the heavens in the prediction of eclipses, and of the
movements of the heavenly bodies generally. This seems reasonable enough; but what we are
not prepared to accept is the obligation which lay on the astronomers to predict the fates of
nations and the destinies of individuals.
It must be remembered that it was the almost universal belief in those days, that all the
celestial spheres revolved in some mysterious fashion around the earth, which appeared by far
the most important body in the universe. It was imagined that the sun, the moon, and the
stars indicated, in the vicissitudes of their movements, the careers of nations and of
individuals. Such being the generally accepted notion, it seemed to follow that a professor who
was charged with the duty of expounding the movements of the heavenly bodies must
necessarily be looked to for the purpose of deciphering the celestial decrees regarding the fate
of man which the heavenly luminaries were designed to announce.
file:///D|/Great Astronomers (Ball, R. S.)/greatastronomers2.htm (41 of 156) [03.04.2007 19:19:46]
Great Astronomers
Kepler threw himself with characteristic ardour into even this fantastic phase of the labours of
the astronomical professor; he diligently studied the rules of astrology, which the fancies of
antiquity had compiled. Believing sincerely as he did in the connection between the aspect of
the stars and the state of human affairs, he even thought that he perceived, in the events of
his own life, a corroboration of the doctrine which affirmed the influence of the planets upon
the fate of individuals.
But quite independently of astrology there seem to have been many other delusions current
among the philosophers of Kepler's time. It is now almost incomprehensible how the ablest
men of a few centuries ago should have entertained such preposterous notions, as they did,
with respect to the system of the universe. As an instance of what is here referred to, we may
cite the extraordinary notion which, under the designation of a discovery, first brought Kepler
into fame. Geometers had long known that there were five, but no more than five, regular
solid figures. There is, for instance, the cube with six sides, which is, of course, the most
familiar of these solids. Besides the cube there are other figures of four, eight, twelve, and
twenty sides respectively. It also happened that there were five planets, but no more than
five, known to the ancients, namely, Mercury, Venus, Mars, Jupiter, and Saturn. To Kepler's
lively imaginations this coincidence suggested the idea that the five regular solids
corresponded to the five planets, and a number of fancied numerical relations were adduced
on the subject. The absurdity of this doctrine is obvious enough, especially when we observe
that, as is now well known, there are two large planets, and a host of small planets, over and
above the magical number of the regular solids. In Kepler's time, however, this doctrine was
so far from being regarded as absurd, that its announcement was hailed as a great intellectual
triumph. Kepler was at once regarded with favour. It seems, indeed, to have been the
circumstance which brought him into correspondence with Tycho Brahe. By its means also he
became known to Galileo.
The career of a scientific professor in those early days appears generally to have been marked
by rather more striking vicissitudes than usually befall a professor in a modern university.
Kepler was a Protestant, and as such he had been appointed to his professorship at Gratz. A
change, however, having taken place in the religious belief entertained by the ruling powers of
the University, the Protestant professors were expelled. It seems that special influence having
been exerted in Kepler's case on account of his exceptional eminence, he was recalled to Gratz
and reinstated in the tenure of his chair. But his pupils had vanished, so that the great
astronomer was glad to accept a post offered him by Tycho Brahe in the observatory which
the latter had recently established near Prague.
On Tycho's death, which occurred soon after, an opening presented itself which gave Kepler
the opportunity his genius demanded. He was appointed to succeed Tycho in the position of
imperial mathematician. But a far more important point, both for Kepler and for science, was
that to him was confided the use of Tycho's observations. It was, indeed, by the discussion of
Tycho's results that Kepler was enabled to make the discoveries which form such an important
part of astronomical history.
file:///D|/Great Astronomers (Ball, R. S.)/greatastronomers2.htm (42 of 156) [03.04.2007 19:19:46]
Great Astronomers
Kepler must also be remembered as one of the first great astronomers who ever had the
privilege of viewing celestial bodies through a telescope. It was in 1610 that he first held in his
hands one of those little instruments which had been so recently applied to the heavens by [ Pobierz całość w formacie PDF ]