This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
The rules, then, which we follow on all Classic work to-day must be considered not as the principles which governed the Greek designers, but as those which we have invented in order to render the use of the Orders easier and more available without great errors of proportion.
It is quite impossible at this day to expect to know the principles which the Classic designers actually followed. Every year there are discovered new variations from the supposed rules which we have applied. It is now known, for instance, that in the Parthenon, at Athens, every supposedly straight line was laid out and determined on some flexible principle of curves proportioned, probably, solely with regard to their final effect upon the eye of the observer.
Superiority of Greek Architecture. Greek civilization developed refinement and subtlety of taste in architecture to a point that architecture has never since attained. The best buildings erected by the Greeks combine such dissimilar qualities as richness, simplicity, magnitude and strength, with refinement and harmony.
Contrary to the general impression regarding the coldness and strict formalism of Greek architecture, probably no people have ever combined Classic architectural forms with more variety, or with more insistence upon the flexibility and interest of their compositions.
Refinement of Lines. No one understood more thoroughly than the Greek artists the abuses and defects of a mathematical system when applied to a vital art. They were compelled to progress beyond this limitation before they succeeded in creating an architecture that was worthy of being included among the Fine Arts; while of no period since has it been possible to give its architecture front rank among them. The ancient Greeks considered the whole effect of their architecture largely with regard to the eye of the beholder, and this principle seems to have been more thoroughly understood by them than by any succeeding nation of builders. As all their masses and details were carefully studied with this optical effect in mind, so nearly all the lines in their work-both horizontal and vertical-curve; and the curves were studied with the apparent intention of counteracting certain awkward optical defects which might be occasioned by the use of a mechanical exactitude in straight and rectangular lines.
These principles the Greeks developed and refined to an almost incalculable degree, while their application was broadened until they subtly varied almost every supposedly straight line. The student of their architecture is nowadays very careful about accepting from casual observation of the effect of the building, the apparent means by which this effect was produced.
Lines in the Parthenon. In the Parthenon, considered as one of the best examples of architecture of all time, late discoveries and more exact measurements have developed the fact that there is probably not an exactly straight line in the entire structure. The most careful study was given to every part of this beautiful building, from every possible point of observation. In the front, for instance, the stylobate upon which the columns rest is slightly higher at the center than at each end, in order to prevent any appearance of dropping at this point as would have been inevitable if it were laid out on a perfectly straight line; the lines of the entablature were in turn slightly raised at the center so that it would not appear to sag; the highest point, again, is not exactly in the center, but to one side, where the building would be seen by anyone approaching from the Propylaea, the entrance to the Acropolis. The columns of the colonnade around the building are all slightly out of the perpendicular; they incline or lean back toward the center, so that the axes, if prolonged to a long distance above the building, would all finally meet at one vanishing point. This is true in all its meanings. Not only does the entire colonnade along the side, for instance, lean back in plane toward the parallel center line of the building along the ridge of the roof, but the columns, as they approach the two ends of the building, lean back toward the center line of the respective elevations. This is true on all four sides of the building, in order to have the sloping lines of the columns correctly intersect at each angle. By referring to the cuts this will be made more clear. Fig. 35 shows two perpendicular sections through the colonnade, with the column placed beyond the face of the enclosing wall of the building. The column at the left is shown with its axis perpendicular and at right angles to a horizontal line. This is the way the Greeks did not use the column. At the right is shown a column employed in their customary manner. Here the dotted line dropped from the inside of the architrave of the crowning entablature discloses the fact that the axis of the column is sloping back at the top toward the enclosing interior wall of the building; while the face of the frieze and entablature above also follows, though more slightly, this same gradual slope. In this example the taper of the column is exaggerated in order to emphasize the theory of its arrangement.
Fig. 36 is a plan of the frieze of the Greek Doric Order, showing the columns placed beneath it under every alternate triglyph. This drawing indicates the plans of the columns at the neck and base in relation to each other, and discloses the fact that their centers, while on a perpendicular line in front elevation, are not directly over each other in plan, the center of the column at the neck being placed behind the center at the base in order to produce the effect shown at the right in Fig. 35. At the corner, the center of the column at the neck is necessarily slanted in on each elevation, as is shown on this plan. This will indicate the first stage of the development of this theoretical system, which is shown more clearly in Fig. 37, where the plan of the six-columned Greek Doric porch illustrates the complete working out of this theory. Here we find that each column not only leans back from the face of the building, but also that it is shown inclined toward the center point as well, thus equalizing this gradual inclination of the columns from the one at the corner to the center of any facade of the building, where, if a column were placed, it would be directly perpendicular in elevation while its neck would still incline back from the face of the building. The almost intangible variation of these columns from the perpendicular was made in order that they would not appear to spread outward at the top, and that at the same time the building would present, in its pyramidal form, a more solid and enduring aspect.