Note 462 — Chapter IV · THE SOURCES FOR THE PERIOD 1100–1250 A. D.

Most of Albertus Magnus’ (1193–1280) many and voluminous works, the greatest repertory of Aristotelian science of the Christian Middle Ages, constitute an immense paraphrase of and commentary on all the writings of Aristotle that were available in the mid-thirteenth century. Albert used many of the titles that were applied in the period to Aristotle’s works and the customary division into books and chapters. Of particular interest from the geographical point of view are: De caelo et mundo (Jammy edit., 1651, vol. ii); Libri meteorum (ibid., vol. ii); De natura locorum (ibid., vol. v), and De proprietatibus elementorum (ibid., vol. v). Kretschmer, Phys. Erdk., 1889, passim, and Werner, Kosm. Wilhelm von Conches, 1873, passim, give a fairly satisfactory general idea of the more important contributions of Albert to cosmology and physical geography.

In the second book of the De caelo et mundo Albert declares that the earth is spherical because the particles which compose it are drawn toward the center of the universe and, in striving to attain that point, arrange themselves symmetrically in the form of a sphere. He gives as proofs of the sphericity of the earth arguments that were familiar to writers of antiquity (see above, p. 368, note 33).

In the Libri meteorum (Meteorology) much material will be found on the atmosphere, on the waters, and on earthquakes. Albert thought that the winds are caused by an earthy humor raised by the sun (Werner, op. cit., pp. 351–352; compare this theory with the theory of Seneca and of William of Conches, pp. 171–172, above). He thought that the areas of the earth’s surface covered by water are much more extensive than those represented by land and that large rivers spring from great 407cavities in the interior of the earth. These cavities, he maintained, usually correspond in position to the major mountain ranges.

Points of physical geography are also treated at some length in the De proprietatibus elementorum (based upon the pseudo-Aristotelian work of the same title): hot springs, volcanoes, tides, the Deluge, the origin of mountains by earthquakes and by erosion. Albert expresses vigorous opposition to the theory of the periodic rotation of land and sea around the earth’s surface under astrological influences (see above, pp. 14 and 83), but he believed, none the less, that the heavenly bodies through their varying motions and conjunctions may bring to bear powerful local changes in conditions of dampness and dryness which in turn may even produce interchanges of areas of land and sea. He refers to the discovery of the rudder of a great ship when a certain well was dug in muddy ground as evidence of gradual alterations in the relative level of land and sea (Kretschmer, op. cit., p. 125).

In a great many respects the De natura locorum is the most valuable of Albert’s books from the geographical point of view. Kretschmer goes so far as to declare that this work reveals to us in Albert the first great geographer since antiquity (ibid., p. 139). Tractatus I treats, among other matters, of latitudes and longitudes, of the habitable and uninhabitable parts of the earth’s surface, and of climates. Albert denies the older view that the equatorial regions are totally uninhabitable on the ground that people were actually known to dwell therein. Moreover, he was inclined to the belief that the countries near the equator are more temperate and pleasant than those nearer the tropics (see above, p. 164). Albert’s “climatic observations in the Liber de natura locorum have at all times aroused undivided admiration, and we find in them the first attempt at a comparative geography” (Kretschmer, op. cit., p. 139). This applies more especially to his observations regarding the influences of mountains, seas, woods, and other topographic features upon climate. These would well repay careful comparison with the views of William of Conches upon the same topics (see above, p. 178). Tractatus III of the De natura locorum is a “cosmographia,” or description of the regions of the world, following the usual medieval scheme.