deposits: thus anticipating by eight centuries the results of modern science.
Two
hundred years after Avicenna there appeared one of the grandest
figures of the middle ages—Albertus Magnus, or Albert the Great.
Among
the great works that we owe to this gifted man, or at least to his
impulse and direction, is a treatise upon minerals, of which the
illustrious chemist M. Dumas has said, " That which characterizes the
treatise De Rebus Metallicis is the learned, precise, and often
elegant exposition of the opinions of the ancients and of the Arabs; it
is the methodical discussion of these which discloses at once the
practised writer and the attentive observer."
In
this treatise Albertus Magnus discusses precious stones; and while
devoting a considerable space to the extraordinary properties of these
beautiful productions, he carefully distinguishes a certain number of
them, and indicates methods of obtaining several sorts of false gems.
Another
illustrious genius of the middle ages— the friend and disciple of
Albertus Magnus—St. Thomas Aquinas, whose voluminous works even surpass
in extent those of his master, has written a treatise upon the Nature of Minerals, in which some very curious passages occur, especially on the fabrication of artificial stones.
