sities. Even to the end of the seventeenth
century the oath generally required of professors of astronomy over a
large part of Europe prevented their teaching that comets are heavenly
bodies obedient to law. Efforts just as earnest were made to fasten into
students' minds the theological theory. Two or three examples out of
many may serve as types. First of these may be named the teaching of
Jacob Heerbrand, professor at the University of Tubingen, who in 1577
illustrated the moral value of comets by comparing the Almighty sending
a comet, to the judge laying the executioner's sword on the table
between himself and the criminal in a court of justice; and, again, to
the father or schoolmaster displaying the rod before naughty children.
A little later we have another churchman of great importance in that
region, Schickhart, head pastor and superintendent at Goppingen,
preaching and publishing a comet sermon, in which he denounces those who
stare at such warnings of God without heeding them, and compares them
to "calves gaping at a new barn door." Still later, at the end of the
seventeenth century, we find Conrad Dieterich, director of studies at
the University of Marburg, denouncing all scientific investigation of
comets as impious, and insisting that they are only to be regarded as
"signs and wonders."(103)

(103) For the effect of the anti-Pythagorean oath, see Prowe,
Copernicus; also Madler and Wolf. For Heerbrand, see his Von dem
erschrockenlichen Wunderzeichen, Tubingen, 1577. For Schickart, see
his Predigt vom Wunderzeichen, Stuttgart, 1621. For Deiterich, see his
sermon, described more fully below.

The results of this ecclesiastical pressure upon science in the
universities were painfully shown during generation after generation, as
regards both professors and students; and examples may be given typical
of its effects upon each of these two classes.

The first of these is the case of Michael Maestlin. He was by birth a
Swabian Protestant, was educated at Tubingen as a pupil of Apian, and,
after a period of travel, was settled as deacon in the little parish
of Backnang, when the comet of 1577 gave him an occasion to apply his
astronomical studies. His minute and accurate observation of it is to
this day one of the wonders of science. It seems almost impossible that
so much could be accomplished by the naked eye. His observations agreed
with those of Tycho Brahe, and won for Maestlin the professorship of