From sculpture we pass to the sister art of architecture. Here we can safely affirm that Periclean Athens reached perfection within the limits it had set for itself--namely, the Doric style. For temple architecture the religious feeling of the day had prescribed a definite programme which it would have been almost blasphemy to outstep. That is to say, the outline of the temple was bound to correspond to the norm of Doric architecture, laid down more than a century before. The artist’s originality was therefore confined to the task of improving its details in a manner which would pass unnoticed by the general public, who would but vaguely feel a heightened sense of rhythm and harmony. Here we find proof that Greek simplicity is the outcome of extreme subtlety. Until Penrose every one had imagined the lines of the Parthenon to be straight. On the contrary, the apparently flat stylobate or floor rises 1 in 450 towards the centre over a length of 228 and a breadth of 101 feet. The columns do not only taper, as they seem to do, but they swell in the middle in order to counteract the diminishing effect of light behind them, although in pure Greek work the diameter of the shaft is never greater than that of the base. The axis of the outside columns slopes inwards 1 in 106; the inner columns have a slightly smaller inclination, 1 in 150. Even the fluting is studied; the fine shadow effect is produced by diminishing the width but not the depth of the grooves as they approach the echinus. Nor are the columns all exactly the same thickness, for the corner pillars are made a little higher and thicker than their neighbours, because a fiercer light beats on them. Like the stylobate, the entablature also curves upward in the centre, but still more slightly--2 inches in 100 feet. The planes of the moulding are sometimes inclined forwards to prevent foreshortening. Thus to secure the effect of straightness Ictinus cut every stone of this great building on a slant measured to a hair’s breadth. To my lay mind these facts throw a revealing light upon the nature of Greek art and the true meaning of Greek simplicity. Judge of the self-restraint shown by Ictinus (and of course entasis is not confined to the Parthenon) in expending this infinite trouble in a matter which would escape the eye of nine out of ten spectators. Nine out of ten? Yes, but the tenth might be a brother architect--or it might be Pallas Athena. Now that the measuring-tape has proved how subtle is Greek simplicity in one art, we must be prepared for it in other arts where we cannot measure so accurately--in literature, for example, when Euripides seems commonplace or Socrates illogical.