1. SINCE the origin and invention of the orders of columns have been described above, I think it not out of place to speak in the same way about their ornaments, showing how these arose and from what original elements they were devised. The upper parts of all buildings contain timber work to which various terms are applied. And not only in its terminology but actually in its uses it exhibits variety. The main beams are those which are laid upon columns, pilasters, and antae; tie-beams and rafters are found in the framing. Under the roof, if the span is pretty large, are the crossbeams and struts; if it is of moderate extent, only the ridgepole, with the principal rafters extending to the outer edge of the eaves. Over the principal rafters are the purlines, and then above these and under the roof-tiles come the common rafters, extending so far that the walls are covered by their projection.
2. Thus each and every detail has a place, origin, and order of its own. In accordance with these details, and starting from carpenter's work, artists in building temples of stone and marble imitated those arrangements in their sculptures, believing that they must follow those inventions. So it was that some ancient carpenters, engaged in building somewhere or other, after laying the tie-beams so that they projected from the inside to the outside of the walls, closed up the space between the beams, and above them ornamented the coronae and gables with carpentry work of beauty greater than usual; then they cut off the projecting ends of the beams, bringing them into line and flush with the face of the walls; next, as this had an ugly look to them, they fastened boards, shaped as triglyphs are now made, on the ends of the beams, where they had been cut off in front, and painted them with blue wax so that the cutting off of the ends of the beams, being concealed, would not offend the eye. Hence it was in imitation of the arrangement of the tie-beams that men
3. Later, others in other buildings allowed the projecting principal rafters to run out till they were flush with the triglyphs, and then formed their projections into simae. From that practice, like the triglyphs from the arrangement of the tie-beams, the system of mutules under the coronae was devised from the projections of the principal rafters. Hence generally, in buildings of stone and marble, the mutules are carved with a downward slant, in imitation of the principal rafters. For these necessarily have a slanting and projecting position to let the water drip down. The scheme of triglyphs and mutules in Doric buildings was, therefore, the imitative device that I have described.
4. It cannot be that the triglyphs represent windows, as some have erroneously said, since the triglyphs are placed at the corners and over the middle of columns—places where, from the nature of the case, there can be no windows at all. For buildings are wholly disconnected at the corners if openings for windows are left at those points. Again, if we are to suppose that there were open windows where the triglyphs now stand, it will follow, on the same principle, that the dentils of the Ionic order have likewise taken the places of windows. For the term “metope” is used of the intervals between dentils as well as of those between triglyphs. The Greeks call the seats of tie-beams and rafters o)pai/, while our people call these cavities columbaria (dovecotes). Hence, the space between the tie-beams, being the space between two “opae,” was named by them meto/ph.
5. The system of triglyphs and mutules was invented for the Doric order, and similarly the scheme of dentils belongs to the Ionic, in which there are proper grounds for its use in buildings. Just as mutules represent the projection of the principal rafters, so dentils in the Ionic are an imitation of the projections of the common rafters. And so in Greek works nobody ever put dentils under mutules, as it is impossible that common rafters should be underneath principal rafters. Therefore, if that which
6. For in all their works they proceeded on definite principles of fitness and in ways derived from the truth of Nature. Thus they reached perfection, approving only those things which, if challenged, can be explained on grounds of the truth. Hence, from the sources which have been described they established and left us the rules of symmetry and proportion for each order. Following in their steps, I have spoken above on the Ionic and Corinthian styles, and I shall now briefly explain the theory of the Doric and its general appearance.
1. SOME of the ancient architects said that the Doric order ought not to be used for temples, because faults and incongruities were caused by the laws of its symmetry. Arcesius and Pytheos said so, as well as Hermogenes. He, for instance, after getting together a supply of marble for the construction of a Doric temple, changed his mind and built an Ionic temple to Father Bacchus with the same materials. This is not because it is unlovely in appearance or origin or dignity of form, but because the arrangement of the triglyphs and metopes (lacunaria) is an embarrassment and inconvenience to the work. . For the triglyphs ought to be placed so as to correspond to the centres of the columns, and the metopes between the triglyphs
3. However, since our plan calls for it, we set it forth as we have received it from our teachers, so that if anybody cares to set to work with attention to these laws, he may find the proportions stated by which he can construct correct and faultless examples of temples in the Doric fashion. Let the front of a Doric temple, at the place where the columns are put up, be divided, if it is to be tetrastyle, into twenty-seven parts; if hexastyle, into forty-two. One of these parts will be the module (in Greek e)mba/ths); and this module once fixed, all the parts of the work are adjusted by means of calculations based upon it.
4. The thickness of the columns will be two modules, and their height, including the capitals, fourteen. The height of a capital will be one module, and its breadth two and one sixth modules. Let the height of the capital be divided into three parts, of which one will form the abacus with its cymatium, the second the echinus with its annulets, and the third the necking. The diminution of the column should be the same as described for Ionic columns in the third book. The height of the architrave, including taenia and guttae, is one module, and of the taenia, one seventh of a module. The guttae, extending as wide as the triglyphs and beneath the taenia, should hang down for one sixth of a module, including their regula. The depth of the architrave on its under side should answer to the necking at the top of the column. Above
5. The width of the triglyph should be divided into six parts, and five of these marked off in the middle by means of the rule, and two half parts at the right and left. Let one part, that in the centre, form a “femur” (in Greek mhro/s). On each side of it are the channels, to be cut in to fit the tip of a carpenter's square, and in succession the other femora, one at the right and the other at the left of a channel. To the outsides are relegated the semichannels. The triglyphs having been thus arranged, let the metopes between the triglyphs be as high as they are wide, while at the outer corners there should be semimetopes inserted, with the width of half a module. In these ways all defects will be corrected, whether in metopes or intercolumniations or lacunaria, as all the arrangements have been made with uniformity.
6. The capitals of each triglyph are to measure one sixth of a module. Over the capitals of the triglyphs the corona is to be placed, with a projection of two thirds of a module, and having a Doric cymatium at the bottom and another at the top. So the corona with its cymatia is half a module in height. Set off on the under side of the corona, vertically over the triglyphs and over the middle of the metopes, are the viae in straight lines and the guttae arranged in rows, six guttae broad and three deep. The spaces left (due to the fact that the metopes are broader than the triglyphs) may be left unornamented or may have thunderbolts carved on them. Just at the edge of the corona a line should be cut in, called the scotia. All the other parts, such as tympana
7. Such will be the scheme established for diastyle buildings. But if the building is to be systyle and monotriglyphic, let the front of the temple, if tetrastyle, be divided into nineteen and a half parts; if hexastyle, into twenty-nine and a half parts. One of these parts will form the module in accordance with which the adjustments are to be made as above described.