618 COSMOS. 



Albertus Magnus, of the family of the Counts of Bollstadt, 

 must also be mentioned as an independent observer in the 

 domain of analytic chemistry. It is true that his hopes were 

 directed to the transmutation of the metals, but in his attempts 

 to fulfil this object, he not only improved the practical manipu- 

 lation of ores, but he also enlarged the insight of men into the 

 general mode of action of the chemical forces of nature. His 

 works contain some extremely acute observations on the 

 organic structure and physiology of plants. He was ac- 

 quainted with the sleep of plants, the periodical opening and 

 closing of flowers, the diminution of the sap during evaporation 

 from the surfaces of leaves, and with the influence of the 

 distribution of the vascular bundles on the indentations of the 

 leaves. He wrote commentaries on all the physical works of 

 the Stagirite, although in that on the history of animals he 

 followed the Latin translation of Michael Scotus from the 

 Arabic.* The work of Albertus Magnus, entitled Liber cosmo- 

 graphicus de natura locorum, is a kind of physical geography. 

 I have found in it observations, which greatly excited my 

 surprise, regarding the simultaneous dependence of climate on 

 latitude and elevation, and the effect of different angles of 

 incidence of the sun's rays in heating the earth's surface. 

 Albertus probably owes the praise conferred on him by 

 Dante, less to himself than to his beloved pupil St. Thomas 

 Aquinas, who accompanied him from Cologne to Paris in 

 1245, and returned with him to Germany in 1248. 



* The greater share of merit in regard to the history of animals 

 belongs to the emperor Frederic II. We are indebted to him for important 

 independent observations on the internal structure of birds. (See 

 Schneider, in Reliqua librorum Frederici II. imperatoris de arte 

 venandi cum avibus, t. i. 1788, in the Preface.) Cuvier also calls this 

 prince of the Hohenstaufen line, the " first independent and original 

 zoologist of the scholastic middle ages." On the correct view of Albert 

 Magnus, on the distribution of heat over the earth's surface under dif- 

 ferent latitudes and at different seasons, see his Liber cosmograpliicus de 

 natura locorum, Argent. 1515, fol. 14b. and 23a. (Examen crit., t. i. 

 pp. 51-58.) In his own observations, we, however, unhappily too often 

 find, that Albertus Magnus shared in the uncritical spirit of his age. 

 He thinks he knows " that rye changes on a good soil into wheat; that 

 from a beech wood which has been hewn down, a birch wood will spring 

 p from the decayed matter; and that from oak-branches stuck into the 

 sarth vines arise." (Compare also Ernst Meyer, Ueber die Botanik des 

 ISien Jahrhunderts, in the Linncea, bd. x. 1836, s. 719.) 



