y troubles at his
home. His father went away after a quarrel with his wife Catherine, and
died abroad. Catherine herself, who seems to have been of a very
unamiable disposition, next quarrelled with her own relatives. It is not
surprising therefore that Kepler after taking his M.A. degree in August,
1591, coming out second in the examination lists, was ready to accept
the first appointment offered him, even if it should involve leaving
home. This happened to be the lectureship in astronomy at Gratz, the
chief town in Styria. Kepler's knowledge of astronomy was limited to the
compulsory school course, nor had he as yet any particular leaning
towards the science; the post, moreover, was a meagre and unimportant
one. On the other hand he had frequently expressed disgust at the way in
which one after another of his companions had refused "foreign"
appointments which had been arranged for them under the Duke's scheme of
education. His tutors also strongly urged him to accept the lectureship,
and he had not the usual reluctance to leave home. He therefore
proceeded to Gratz, protesting that he did not thereby forfeit his claim
to a more promising opening, when such should appear. His astronomical
tutor, Maestlin, encouraged him to devote himself to his newly adopted
science, and the first result of this advice appeared before very long
in Kepler's "Mysterium Cosmographicum". The bent of his mind was towards
philosophical speculation, to which he had been attracted in his
youthful studies of Scaliger's "Exoteric Exercises". He says he devoted
much time "to the examination of the nature of heaven, of souls, of
genii, of the elements, of the essence of fire, of the cause of
fountains, the ebb and flow of the tides, the shape of the continents
and inland seas, and things of this sort". Following his tutor in his
admiration for the Copernican theory, he wrote an essay on the primary
motion, attributing it to the rotation of the earth, and this not for
the mathematical reasons brought forward by Copernicus, but, as he
himself says, on physical or metaphysical grounds. In 1595, having more
leisure from lectures, he turned his speculative mind to the number,
size, and motion of the planetary orbits. He first tried simple
numerical relations, but none of them appeared to be twice, thrice, or
four times as great as another, although he felt convinced that there
was some relation between the motions and the distances, seeing that
when a