The age of Reason, to which Aristotle is about to introduce us, stands in striking contrast to the preceding ages. It cannot escape the reader that what was done by the men of science in Alexandria resembles what is doing in our own times; their day was the foreshadowing of ours. And yet a long and dreary period of almost twenty centuries parts us from them. Politically, Aristotle, through his friendship with Alexander and the perpetuation of the Macedonian influence in Ptolemy, was the connecting link between the Greek age of Faith and that of Reason, as he was also philosophically by the nature of his doctrines. He offers us an easy passage from the speculative methods of Plato to the scientific methods of Archimedes and Euclid. The copiousness of his doctrines, and the obscurity of many of them, might, perhaps, discourage a superficial student, unless he steadily bears in mind the singular authority they maintained for so many ages, and the brilliant results in all the exact parts of human knowledge to which they so quickly led. The history of Aristotle and his philosophy is therefore our necessary introduction to the grand, the immortal achievements of the Alexandrian school. [Sidenote: Biography of Aristotle.] Aristotle was born at Stagira, in Thrace, B.C. 384. His father was an eminent author of those times on subjects of Natural History; by profession he was a physician. Dying while his son was yet quite young, he bequeathed to him not only very ample means, but also his own tastes. Aristotle soon found his way to Athens, and entered the school of Plato, with whom it is said he remained for nearly twenty years. During this period he spent most of his patrimony, and in the end was obliged to support himself by the trade of a druggist. At length differences arose between them, for, as we shall soon find, the great pupil was by no means a blind follower of the great master. In a fortunate moment, Philip, the King of Macedon, appointed him preceptor to his son Alexander, an incident of importance in the intellectual history of Europe. It was to the friendship arising through this relation that Aristotle owed the assistance he received from the conqueror during his Asiatic expedition for the composition of "the Natural History," and also gained that prestige which gave his name such singular authority for more than fifteen centuries. He eventually founded a school in the Lyceum at Athens, and, as it was his habit to deliver his lectures while walking, his disciples received the name of Peripatetics, or walking philosophers. These lectures were of two kinds, esoteric and exoteric, the former being delivered to the more advanced pupils only. He wrote a very large number of works, of which about one-fourth remain. [Sidenote: He founds the inductive philosophy.]