When it was said just now that the main lines of a Greek temple are either horizontal or perpendicular, the statement called for qualification.  The elevations of the most perfect of Doric buildings, the Parthenon, could not be drawn with a ruler.  Some of the apparently straight lines are really curved.  The stylobate is not level, but convex, the rise of the curve amounting to 1/450 of the length of the building; the architrave has also a rising curve, but slighter than that of the stylobate.  Then again, many of the lines that would commonly be taken for vertical are in reality slightly inclined.  The columns slope inward and so do the principal surfaces of the building, while the anta-capitals slope forward.  These refinements, or some of them, have been observed in several other buildings.  They are commonly regarded as designed to obviate certain optical illusions supposed to arise in their absence.  But perhaps, as one writer has suggested, their principal office was to save the building from an appearance of mathematical rigidity, to give it something of the semblance of a living thing.

Be that as it may, these manifold subtle curves and sloping lines testify to the extraordinary nicety of Greek workmanship.  A column of the Parthenon, with its inclination, its tapering, its entasis, and its fluting, could not have been constructed without the most conscientious skill.  In fact, the capabilities of the workmen kept pace with the demands of the architects.  No matter how delicate the adjustment to be made, the task was perfectly achieved.  And when it came to the execution of ornamental details, these were wrought with a free hand and, in the best period, with fine artistic feeling.  The wall-band of the Erechtheum is one of the most exquisite things which Greece has left us.

Simplicity in general form, harmony of proportion, refinement of line—­these are the great features of Greek columnar architecture.

One other type of Greek building, into which the column does not enter, or enters only in a very subordinate way, remains to be mentioned—­the theater.  Theaters abounded in Greece.  Every considerable city and many a smaller place had at least one, and the ruins of these structures rank with temples and walls of fortification among the commonest classes of ruins in Greek lands.  But in a sketch of Greek art they may be rapidly dismissed.  That part of the theater which was occupied by spectators—­the auditorium, as we may call it—­was commonly built into a natural slope, helped out by means of artificial embankments and supporting walls.  There was no roof.  The building, therefore, had no exterior, or none to speak of.  Such beauty as it possessed was due mainly to its proportions.  The theater at the sanctuary of Asclepius near Epidaurus, the work of the same architect who built the round building with the Corinthian columns referred to on page 103, was distinguished in ancient times for “harmony