empted to reconcile the speculations of Aristotle
with theological views derived from the fathers. In one very important
respect he improved upon the meteorological views of his great master.
The thunderbolt, he says, is no mere fire, but the product of black
clouds containing much mud, which, when it is baked by the intense heat,
forms a fiery black or red stone that falls from the sky, tearing
beams and crushing walls in its course: such he has seen with his own
eyes.(209)

(209) See Albertus Magnus, II Sent., Op., vol. xv, p. 137, a. (cited
by Heller, Gesch. d. Physik, vol. i, p. 184) and his Liber Methaurorum,
III, iv, 18 (of which I have used the edition of Venice, 1488).

The monkish encyclopedists of the later Middle Ages added little to
these theories. As we glance over the pages of Vincent of Beauvais,
the monk Bartholomew, and William of Conches, we note only a growing
deference to the authority of Aristotle as supplementing that of Isidore
and Bede and explaining sacred Scripture. Aristotle is treated like
a Church father, but extreme care is taken not to go beyond the great
maxim of St. Augustine; then, little by little, Bede and Isidore
fall into the background, Aristotle fills the whole horizon, and his
utterances are second in sacredness only to the text of Holy Writ.

A curious illustration of the difficulties these medieval scholars had
to meet in reconciling the scientific theories of Aristotle with the
letter of the Bible is seen in the case of the rainbow. It is to the
honour of Aristotle that his conclusions regarding the rainbow, though
slightly erroneous, were based upon careful observation and evolved by
reasoning alone; but his Christian commentators, while anxious to follow
him, had to bear in mind the scriptural statement that God had created
the rainbow as a sign to Noah that there should never again be a
Flood on the earth. Even so bold a thinker as Cardinal d'Ailly, whose
speculations as to the geography of the earth did so much afterward in
stimulating Columbus, faltered before this statement, acknowledging that
God alone could explain it; but suggested that possibly never before the
Deluge had a cloud been suffered to take such a position toward the sun
as to cause a rainbow.

The learned cardinal was also constrained to believe that certain stars
and constellations have something to do in causing the rain, since these
would best explain Noah's foreknowledge of the Deluge. In