For many centuries succeeding the Middle Ages, especially from the eleventh to the fifteenth, the metaphysical teachings of Aristotle held a tyrannic sway over the public mind; but they have been gradually yielding to the more lofty and sublime teachings of Plato. His investigations in natural science, however, and his work as a logician and political philosopher, constitute his greatness, and create the enormous influence that he has wielded in the world. "Science owes to him its earliest impulse," says MR. LAWRENCE. "He perfected and brought into form," says DR. WILLIAM SMITH, "those elements of the dialectic art which had been struck out by Socrates and Plato, and wrought them by his additions into so complete a system that he may be regarded as at once the founder and perfecter of logic as an art." Says MAHAFFY, "He has built his politics upon so sound a philosophic basis, and upon the evidence of so large and varied a political experience, that his lessons on the rise and fall of governments will never grow old, and will be perpetually receiving fresh corroborations, so long as human nature remains the same." Aristotle was a friend of the Macedonians, and, on the death of Alexander, he fled, from Athens to Chal'cis, in Euboea, to escape a trial for impiety. There he died in 322 B.C. In the lives of the three great philosophers of Greece--Socrates, Plato, and Aristotle--is embraced what is commonly called "The Philosophical Era of Athens." To this era MILTON has beautifully alluded in his well-known description of the famous city; and for the Academe, or Academia, the beautiful garden that was the resort of the philosophers, EDWIN ARNOLD expresses these sentiments of veneration: Pleasanter than the hills of Thessaly, Nearer and dearer to the poet's heart Than the blue ripple belting Salamis, Or long grass waving over Marathon, Fair Academe, most holy Academe, Thou art, and hast been, and shalt ever be. I would be numbered now with things that were, Changing the wasting fever of to-day For the dear quietness of yesterday: I would be ashes, underneath the grass, So I had wandered in thy platane walks One happy summer twilight--even one. Was it not grand, and beautiful, and rare, The music and the wisdom and the shade, The music of the pebble-paven rills, And olive boughs, and bowered nightingales, Chorusing joyously the joyous things Told by the gray Silenus of the grove, Low-fronted and large-hearted Socrates! Oh, to have seen under the olive blossoms But once--only once in a mortal life, The marble majesties of ancient gods! And to have watched the ring of listeners-- The Grecian boys gone mad for love of truth, The Grecian girls gone pale for love of him Who taught the truth, who battled for the truth; And girls and boys, women and bearded men, Crowding to hear and treasure in their hearts Matter to make their lives a happiness, And death a happy ending. EPICU'RUS AND ZE'NO.