But the Parthenon, so regular, with its vertical and horizontal lines, was curved in every line, with the exception of the gable,--pillars, architrave, entablature, frieze, and cornice, together with the basement--all arched upwards, though so slightly as not to be perceptible, and these curved lines gave to it a peculiar grace which cannot be imitated, as well as solidity. [Sidenote: The Acropolis.] Nearly coeval with the Doric was the Ionic order, invented by the Asiatic Greeks, still more graceful, though not so imposing. The Acropolis is a perfect example of this order. The column is nine diameters in height, with a base, while the capital is more ornamented. The shaft is fluted with twenty-four flutes and alternate fillets, and the fillet is about a quarter the width of the flute. The pediment is flatter than of the Doric order, and more elaborate. The great distinction of the Ionic column is a base, and a capital formed with volutes, with a more slender shaft. Vitruvius, the greatest authority among the ancients in architecture, says that, "the Greeks, in inventing these two kinds of columns, imitated in the one the naked simplicity and dignity of a man, and in the other, the delicacy and ornaments of a woman; the base of the Ionic was the imitation of sandals, and the volutes of ringlets." [Sidenote: Temple of Minerva.] The Corinthian order exhibits a still greater refinement and elegance than the other two, and was introduced toward the end of the Peloponnesian war. Its peculiarity is columns with foliated capitals, and still greater height, about ten diameters, with a more ornamented entablature. Of this order, the most famous temple in Greece was that of Minerva at Tegea, built by Scopas of Paros, but destroyed by fire four hundred years before Christ. Nothing more distinguished Greek architecture than the variety, the grace, and the beauty of the mouldings, generally in eccentric curves. The general outline of the moulding is a gracefully flowing cyma, or wave, concave at one end, and convex at the other, like an Italic _f_, the concavity and convexity being exactly in the same curve, according to the line of beauty which Hogarth describes. [Sidenote: Architecture among the Greeks seen in greatest perfection in temples.]