378 THE POPULAR SCIENCE MONTHLY. 



merely sharpened at the lower end, and so blazing arrows, cleaving 

 and burning everything they touch." * 



But far more important in the thirteenth century was the fact that 

 the most eminent scientific authority of that age, Albert the Great, 

 Bishop of Ratisbon, attempted to reconcile the speculations of Aris- 

 totle with the 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 prod- 

 uct 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.f 



The monkish encyclopedists of the later middle ages added little 

 to these theories. As we glance over the pages of Vincent of Beau- 

 vais, Bartholomew of Glanville, 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 Saint 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 mediaeval 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 

 honor 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, were brought up against the scriptural statement that God 

 had created the rainbow as a sign to Noah that there should never 

 asrain be a Flood on the earth. Even so bold a thinker as Cardinal 

 Pierre 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 sug- 

 gested that possibly never before the deluge had a cloud been suffered 

 to take such a position toward the sun as to cause a rainbow. J 



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 

 connection with this scriptural doctrine of winds came a scriptural 



* Sec Joannes a S. Gcminiano, " Summa," c. To. 



f See Albertus Magnus, " II Sent.," Opp. xv, 137, a. (cited by ITellcr, "Gc?ch. d. Phy- 

 8ik," i, 184) and his " Liber Methauroruni," III, iv, 18 (of which I have used the edition 

 of Venice, 1488). 



% See his "Concordia astronomies veritatis cum theologia" (Paris, 1483 in his 

 " Imago mundi" and Venice, 1490); also Eck's commentary on Aristotle's " Mcteoro- 

 logica" (Augsburg, 1519). 



