Column Entasis. In these Orders, the upper diameter is made quite considerably less than the lower diameter, and the column is "tapered" or "swelled" in outline. It thus represents an inclined profile with an outline tapering or swelling from the lower to the upper diameter. This profile is generally given a form slightly curved, due to an "entasis" of the middle part, but sometimes the two diameters are joined by a straight line. The smaller and larger diameters, although variable, have a certain relation that is followed in every case, changing the outline of the column and rendering it more or less curved.
In the old Temple of Corinth, the diminution of the upper part equals one-fourth a diameter; in the Temple of Poseidon at Pæstum, it is one-third; in the Temple of Theseus, the Parthenon, and the Temple of Zeus, two-ninths; in the Temple of Zeus at Nemea, one-fifth; and in the Portico of Philip one-sixth.
To trace the growth and gradual refinement of the proportions of the first Greek Order, it is helpful to have an idea of the comparative date and column dimensions of the best known examples; and for this purpose it becomes necessary to revert to the unit of the measure—the diameter of the columns at the base.
Evidently the builders recognized that the effect produced by these first columns was stumpy and ungraceful. They found that they were too short for their height, that the diameter at the neck was much too small in proportion to that at the base, and that the first used mouldings were uncouth; and these faults they apparently set them selves to rectify in succeeding examples. So far as we can trace the dates of the Greek temple ruins—allowing, of course, for the difference in locality, which must sometimes have prevented the study, by the builders, of examples in another country—the proportions of the Doric Order show a continuous progress toward the perfection to which it finally attained in the Golden or Periclean Age, the fifth century before Christ.
Theory of Derivation of Doric Order from Wooden Construction. The details of the Doric Order, and especially of the entablature, are supposed to have been borrowed from the timber framing of the smaller and earlier buildings of the Greeks, and therefore to be a copy, in stone, of the forms and parts of a wooden building.
It was the theory of Vitruvius, the principal ancient writer upon architecture, that the gradual substitution of stone for wood as a building material would naturally account for certain elements in which wood construction in the Doric Order seems to be imitated in stone. He says that stone columns took the place of wooden posts,
and the fluting of these columns corresponded to the chamfers of the posts. The stylobate, plinth, and base, he derives from a sill or beam on which the posts rested. The capital is 'merely a plate or block, intended to shorten the span of the joists resting upon the posts, and to give the joists a broader bearing upon the points of their support. The triglyphs correspond to the ends of the ceiling beams, and the void spaces between these beams are the metopes, which were at first left open for light and ventilation, and which were filled in with decorated slabs only at a later period. The rafters of the roof projecting beyond the frame of the building gave the suggestion for a cornice, and the mutules of the corona are the ends of these rafters.
The guttæ or drops have the shape of pins used in the framing of timber, while the slope of the roof itself gives the outline of the pedi ment. These suppositions are not beyond criticism and can indeed be met by valid objections, but they are at least plausible and interest ing, taken altogether.
Belittling, in a way, as this explanation seems, it appears to have had general acceptance up to the present time, and has been at least ingeniously supported by many theorists to whom it has appealed. The two cuts, Figs. 52 and 53, indicate the possible par allels in wood and stone whereby this growth may have occurred. In any case we must allow that The stone version is not a mere copy of the original, but that it has become very highly idealized in most of its parts. The tri glyphs and metopes represent what may have been the ends of beams and the spaces between them; and the mutules—sloping as they are in most of the Greek examples—may represent the ends of rafters. Referring particularly to Fig. 52, and imagining that the column below is done away with, and that the architrave is merely the upper portion of a blank stone wall, as is shown in C, Fig. 54, we shall try to find another and more logical reason for the treatment of the frieze above it, than that one generally allowed.