their time. The fame which in the Middle Ages surrounded the names of these four great men was proportionate to the general diffusion of this opinion of their endowments. Albertus was the first scholastic who systematically reproduced the philosophy of Aristotle with reference to the Arabian commentators and who remodelled it to meet the requirements of ecclesiastical dogma. The cause of the new development of scholasticism in the thirteenth century was the translation, for the first time, into Latin of the complete works of Aristotle, which latter only came to the knowledge of the scholastics (1210–1225) through the agency of Arabian philosophy. The leading Arabian philosophers were Avicenna, Averroës and Avempace, whilst, in the new movement, Albertus Magnus, St. Thomas Aquinas and Joannes Duns Scotus represented the culmination of scholastic thought and its consolidation into a system.[14] Albertus, according to Humboldt, must be mentioned as an independent investigator in the domain of analytic chemistry, improving as he did the practical manipulation of ores, and having actually enlarged the insight of men into the general mode of action of the chemical forces of nature. His “Liber Cosmographicus” is a singularly able presentment of physical geography. He also wrote very extensively upon plant-life, and is the author of commentaries upon practically all the physical works of the Stagirite, although in the commentary on Aristotle’s “Historia Animalium” he is said to have closely followed the Latin translation of Michael Scotus from the Arabic. Albertus doubtless owes the praise conferred upon him by Dante less to himself than to his beloved pupil Aquinas, who accompanied him from Cologne to Paris in 1245, and returned with him to Germany in 1248. “Questi, che m’ è a destra più vicino, Frate e maestro fummi; ed’ esse Alberto E’ di Cologna, ed io Thomas d’Aquino.” “Il Paradiso,” X. 97–99. Gilbert refers to Albertus in “De Magnete,” Book I. chaps, i. and vi., also in Book II. chap. xxxviii.