successive series of inquiries, until they elevated themselves above matter, above experience, even to the loftiest abstractions, and until they classified the laws of thought. It is curious how speculation led to demonstration, and how inquiries into the world of matter prepared the way for the solution of intellectual phenomena. Philosophy kept pace with geometry, and those who observed nature also gloried in abstruse calculations. Philosophy and mathematics seem to have been allied with the worship of art among the same men, and it is difficult to say which more distinguished them, aesthetic culture or power of abstruse reasoning. [Sidenote: Thales.] [Sidenote: Water the vital principle of Nature.] We do not read of any remarkable philosophical inquirer until Thales arose, the first of the Ionian school. He was born at Miletus, a Greek colony in Asia Minor, about the year B.C. 636, when Ancus Martius was king of Rome, and Josiah reigned at Jerusalem. He has left no writings behind him, but he was numbered as one of the seven wise men of Greece. He was numbered with the wise men on account of his political sagacity and wisdom in public affairs. [Footnote: Miller, Hist, of Grec. Lit., ch. xvii.] "And he, 't is said, did first compute the stars Which beam in Charles' wain, and guide the bark Of the Phoenician sailor o'er the sea." He was the first who attempted a logical solution of material phenomena, without resorting to mythical representations. Thales felt that there was a grand question to be answered relative to the _beginning of things_. "Philosophy," it has been well said, "may be a history of _errors_, but not of _follies_" It was not a folly, in a rude age, to speculate on the first or fundamental principle of things. He looked around him upon Nature, upon the sea and earth and sky, and concluded that water or moisture was the vital principle. He felt it in the air, he saw it in the clouds above, and in the ground beneath his feet. He saw that plants were sustained by rain and by the dew, that neither animal nor man could live without water, and that to fishes it was the native element. What more important or vital than water? It was the _prima materia_, the [Greek: archae], the beginning of all things--the origin of the world. [Footnote: Aristotle, _Metaph._, 1. c. 3; Diog. Laertius, _Thales_.] I do not here speak of his astronomical and geometrical labors--as the first to have divided the year into three hundred and sixty-five days. He is celebrated also for practical wisdom. "Know thyself," is one of his remarkable sayings. But the foundation principle of his philosophy was that water is the first cause of all things--the explanation, of the origin of the universe. How so crude a speculation could have been maintained by so wise a man it is difficult to conjecture. It is not, however, the _reason_ which he assigns for the beginning of things which is noteworthy, so much as the