EMPEDOCLES AND DEMOCRITUS.--In the teachings of Empedocles (about 492-432 B.C.) and Democritus (about 460-370 B.C.) we meet with many speculations respecting the constitution of matter and the origin of things which are startlingly similar to some of the doctrines held by modern scientists. Empedocles, with the evolutionists of to-day, taught that the higher forms of life arise out of the lower; Democritus conceived all things to be composed of invisible atoms, all alike in quality, but differing in form and combination. THE SOPHISTS.--The Sophists, of whom the most noted were Protagoras, Gorgias, and Prodicus, were a class of philosophers or teachers who gave instruction in rhetoric and the art of disputation. They travelled about from city to city, and contrary to the usual custom of the Greek philosophers, took fees from their pupils. They were shallow but brilliant men, caring more for the dress in which the thought was arrayed than for the thought itself, more for victory than for truth; and some of them inculcated a selfish morality. The better philosophers of the time despised them, and applied to them many harsh epithets, taunting them with selling wisdom, and accusing them of boasting that they could "make the worse appear the better reason." SOCRATES.--Volumes would not contain what would be both instructive and interesting respecting the lives and works of the three great philosophers Socrates, Plato, and Aristotle. We can, however, accord to each only a few words. Of these three eminent thinkers, Socrates (469-399 B.C.), though surpassed in grasp and power of intellect by both Plato and Aristotle, has the firmest hold upon the affections of the world. Nature, while generous to the philosopher in the gifts of soul, was unkind to him in the matter of his person. His face was ugly as a satyr's, and he had an awkward, shambling walk, so that he invited the shafts of the comic poets of his time. He loved to gather a little circle about him in the Agora or in the streets, and then to draw out his listeners by a series of ingenious questions. His method was so peculiar to himself that it has received the designation of the "Socratic dialogue." He has very happily been called an _educator_, as opposed to an _instructor_. In the young men of his time Socrates found many devoted pupils. The youthful Alcibiades declared that "he was forced to stop his ears and flee away, that he might not sit down by the side of Socrates and grow old in listening." [Illustration: SOCRATES.] Socrates was unfortunate in his domestic relations. Xanthippe, his wife, seems to have been of a practical turn of mind, and unable to sympathize with the abstracted ways of her husband. This great philosopher believed that the proper study of mankind is man, his favorite maxim being "Know Thyself"; hence he is said to have brought philosophy from the heavens and introduced it to the homes of men.