THE PREDECESSOES OF COPERNICUS. 337 



seat of life; the brain first receives impressions; the nerves; the anatomy of 

 the eye; its humors; the function of vision; vision is the result of radiation; 

 vision is not completed in the eye but in the brain; matter is infinitely divisible; 

 as many divisions can be made in a grain of millet as in the diameter of the 

 world; theory of color; conditions of vision; time is required for the propaga- 

 tion of light; double images; radiations from the object and from the eye; 

 perception; the Milky Way is a multitude of small stars clustered; shooting 

 stars are probably bodies of small magnitudes seen by (persistent vision) ; 

 phases of the moon; the surface of the heavens is spherical; illusions respecting 

 relative motion; twinkling of stars; animals pass through a train of mental 

 processes akin to syllogistic reasoning, though they can not put it into a logical 

 figure; they have a storehouse of mental impressions; can generalize and draw 

 conclusions. 



On Reflected Vision. — The angles of incidence and reflection are equal 

 whether the mirror be plane or spherical; mirrors; illusions; color; refraction; 

 by refraction great wonders may be wrought; small things may be made to 

 seem great, distant things near. 



Moral Philosophy. — Civic morality; personal morality; we must pursue our 

 steady course, not diverted from it by the varying blasts of opinion; proof of 

 the truth of the Christian religion; revelation is necessary; it is not enough 

 for the reason to be convinced in this matter — the heart must be stirred. If 

 we are made one with God and Christ, to what greater good can we aspire? 



The thirteenth century is memorable by the appearance of three 

 great men, Roger Bacon, Albertus Magnus and St. Thomas Aquinas. 

 Albert was born in Suabia in 1193, the descendant of a celebrated and 

 powerful family. He may be reckoned as the best product of the 

 middle ages. He studied in Padua and Bologna, taught at Cologne 

 and Paris (1245) and returned to Cologne. He became provincial of 

 the Dominicans in Germany in 1254, and was Bishop of Eatisbon 

 (in 1260) till he resigned about 1263. He was the friend of kings 

 and popes. His great service to the church was a systematic presenta- 

 tion of the philosophy of Aristotle with a full accompaniment of Arab 

 commentary. Among his contemporaries he was known as Doctor 

 Universalis, and, in the history of the world, is especially famous for 

 his works on physical science. Like all the learned men of his time 

 he was supposed by the vulgar to practise magic and, as a matter of 

 course, he sought the philosopher's stone. It was even currently be- 

 lieved that he paid the large debt of his bishopric of Eatisbon with 

 transmuted gold. The flowers tbat he grew in the winter time, which 

 the wondering townsfolk called magical, were in all likelihood the 

 product of the first hot-house constructed in Europe. An edition of 

 his works in twenty-one volumes was first published in 1651. This 

 complete collection shows, in the first place, that he was thoroughly 

 familiar with all the learning of the Arabs up to his own time. He 

 was to the west what Avicenna was to the east, an encyclopedia of all 

 knowledge. His philosophy is, of course, Aristotle's, elucidated by 

 the schools of Arabia and Spain. His works on physical science are, 

 in a large degree, mere reproductions of Greek treatises, but they are 



VOL. LXIV. — 22. 



