[Sidenote: Albertus Magnus, the Dominican.] Albertus Magnus was born A.D. 1193. It was said of him that "he was great in magic, greater in philosophy, greatest in theology." By religious profession he was a Dominican. Declining the temptations of ecclesiastical preferment, he voluntarily resigned his bishopric, that he might lead in privacy a purer life. As was not uncommon in those days, he was accused of illicit commerce with Satan, and many idle stories were told of the miracles he wrought. At a great banquet on a winter's day, he produced all the beauties of spring--trees in full foliage, flowers in perfume, meadows covered with grass; but, at a word, the phantom pageant was dissolved, and succeeded by appropriate wastes of snow. This was an exaggeration of an entertainment he gave, January 6th, 1259, in the hot-house of the convent garden. He interested himself in the functions of plants, was well acquainted with what is called the sleep of flowers, studied their opening and closing. He understood that the sap is diminished in volume by evaporation from the leaves. He was the first to use the word "affinity" in its modern acceptation. His chemical studies present us with some interesting details. He knew that the whitening of copper by arsenic is not a transmutation, but only the production of an alloy, since the arsenic can be expelled by heat. He speaks of potash as an alkali; describes several acetates; and alludes to the blackening of the skin with nitrate of silver. [Sidenote: Roger Bacon, discoveries of.] Contemporary with him was Roger Bacon, born A.D. 1214. His native country has never yet done him justice, though his contemporaries truly spoke of him as "the Admirable Doctor." The great friar of the thirteenth century has been eclipsed by an unworthy namesake. His claims on posterity are enforced by his sufferings and ten years' imprisonment for the cause of truth.