detail into their discovery, meantime catching a glimpse of the
life history of the remarkable man whose name they bear.


JOHANN KEPLER AND THE LAWS OF PLANETARY MOTION

Johann Kepler was born the 27th of December, 1571, in the little
town of Weil, in Wurtemburg. He was a weak, sickly child, further
enfeebled by a severe attack of small-pox. It would seem
paradoxical to assert that the parents of such a genius were
mismated, but their home was not a happy one, the mother being of
a nervous temperament, which perhaps in some measure accounted
for the genius of the child. The father led the life of a
soldier, and finally perished in the campaign against the Turks.
Young Kepler's studies were directed with an eye to the ministry.
After a preliminary training he attended the university at
Tubingen, where he came under the influence of the celebrated
Maestlin and became his life-long friend.

Curiously enough, it is recorded that at first Kepler had no
taste for astronomy or for mathematics. But the doors of the
ministry being presently barred to him, he turned with enthusiasm
to the study of astronomy, being from the first an ardent
advocate of the Copernican system. His teacher, Maestlin,
accepted the same doctrine, though he was obliged, for
theological reasons, to teach the Ptolemaic system, as also to
oppose the Gregorian reform of the calendar.

The Gregorian calendar, it should be explained, is so called
because it was instituted by Pope Gregory XIII., who put it into