How to Study Architecture by Charles H. Caffin (reading the story of the .TXT) 📖

expression of their taste for richness. The shaft was either smooth, as in the early example of the Pantheon (B.C. 27), or fluted as in the great temple of Castor and Pollux; the heights in these two cases being respectively 9¾ and 10 diameters. A special base was designed, consisting of tori, scotia, and fillets, resting on a square plinth.

The inverted bell of the capital was surrounded by an upper and lower row of acanthus leaves, which differ from the Hellenic forms in being blunter at the tips. Above the rows of leaves projected the stalks, or “caulicolæ,” which terminated in spirals, both in the centre of each face and at the angles of the abacus. The four sides of the latter are concave and decorated in the centre with a rosette. In the more sumptuous examples further enrichment of ornament was added to the capital, while the capitals of the Temple of Castor and Pollux present a unique instance of the central spirals being interlaced.

The Corinthian architrave in Hellenic usage consisted, it will be remembered, of three bands, as in the Ionic order. The Romans frequently embellished the middle one with a version of the anthemion motive. They also added enrichments to the bed mould beneath the frieze. The latter was frequently carved with acanthus scrolls, grotesque figures, and ox-skulls, and garlands. The cornice was also enriched with carved ornament, of which the most characteristic were modillions or brackets, which appear to support the cornice.

The Composite order was an invention of the Romans and possibly suggested by the capitals of the Erechtheion in Athens, where the Ionic spirals appear above a necking carved with anthemion ornament. The capital of the Composite order consisted in the upper part of Ionic spirals, often richly decorated with foliage, and in the lower of two rows of acanthus leaves, as in the Corinthian order, which was followed also in the other details of the column and entablature.

The mouldings in Hellenic architecture are distinguished by the refinement of the contours, in Roman by the richness of carved ornament.

The anta, which appears in Greek temples at the corners of the cella walls was developed by the Romans into the pilaster. This was a square pier, projecting about one-sixth of its width from the wall; used either to divide up and decorate the wall surfaces, or to serve as a “respond” to a column. It was frequently fluted and corresponded with the column in its details.

Arch-Vaulting.—The Romans did not invent the arch, but generalised its use and elaborated it into vaulting, thus introducing into architecture an element of construction capable of endless application and lending itself not only to utility but also to variety and magnificence. In doing so they were assisted by their discovery of the use of concrete. By means of supports and sheathings of rough timber, temporarily erected, they were able to cast their arches or vaultings in any form and practically of any size. The concrete “set” quickly and the arch or vaulting thus became a solid mass, which exerted but little thrust and covered the space with the rigidity of a lid or cup.

Such method of construction lessened the tendency of the arch or vaulting to exert a lateral strain or thrust which occurs when the arch is composed of voussoirs or, similarly, separate blocks of stone or brick are used in the vault. It tended to concentrate the strain on the vertical supports. Yet the Romans, though concentration of strains was a chief principle of their building, took no chances in the matter of stability and also distributed the strains. For example, the nave vaulting of a basilica would be reinforced by aisle vaulting, which was carried on walls that were either at right angles or parallel to the nave. But owing to the method of concrete construction and to the facility with which it could be employed, the Romans were able to erect vaults over buildings of complex plan and spaces of great size.

The vaultings were of three kinds:

1. The semicylindrical vault, called also the wagon-headed vault or barrel vault.

2. The cross or groined vault.

3. The dome or semidome.

The semicylindrical vault was a continuous arch spanning an oblong space, a corridor, and sometimes a curved passageway.

The cross or groined vault was used over square spaces, its weight being carried at the four angles. It was formed by the intersection at right-angles of two semicylindrical vaults. When employed over long apartments or corridors, the ceiling was divided into a series of square compartments or bays, each covered by a cross-vault. Since the vaulting in each case was carried upon the corner supports, these became piers, and the wall spaces in between them, being thus relieved of the pressure of the vaulting, could be utilised for the openings of doors and windows. Moreover, a square space could be subdivided into bays, rendering it possible to vault a large area with no interruption to the floor-space except that of the piers.

The dome was used for covering circular spaces, and when the space is small the covering is called a cupola or little cup. Semidomes were employed over recesses.

The finest existing example of a Roman dome is that of the Pantheon, which, however, affords an exception to the usual method of construction. For here, instead of being composed of concrete, thus forming a solid shell, the dome, so far as it has been examined, is found to be built of bricks, laid in almost horizontal courses.

It is to be noted that the so-called “pendentive” dome, supported by arches over a space, square in plan, is not found in strictly Roman buildings and was a development of the Byzantine architects.

The Romans also employed flat roofs and ceilings. In certain of the baths so much iron has been found amid the debris, that it is supposed the roofs were constructed with a framework of this material, fitted together with T joints. Otherwise the ceilings were made of crossed beams, dividing the space into coffers. The exterior of the roofs was covered with a sheathing of terra-cotta tiles or, as in the original roof of the Pantheon, of bronze gilded plates, which now are replaced by lead.

Vault and Wall Decoration.—Sheathing was also applied to the exterior and interior of the whole structure, forming, as it were, a garment of decoration. In the case of vaulting, the interior decoration was composed of stucco coffering; square, hexagonal, or octagonal panels, inclosed within raised framework that was arranged in a geometrical pattern. Sometimes the coffering was replaced by mosaics; which were of two kinds.

1. Opus tessellatum formed of tesseræ or cubes of marble or glass, arranged in patterned designs that often included figures.

2. Opus sectile, in which the tesseræ were cut into various shapes, to form the pattern, as in marquetrie. A rich kind, made of red and green porphyry, was distinguished as Opus Alexandrinum.

At other times the vaulting and walls were covered with hard plaster, wrought to a fine surface, which was polished and frequently embellished with mural painting.

The walls were also overlaid with slabs of coloured marble, in the selection and treatment of which the Romans took a notable pride.

Further, both the exterior and the interior walls were relieved with carved decoration, which took the form of pilasters, arches, mouldings, and panels, encrusted with arabesques. These and the other embellishments could be so easily applied to the concrete shell, that Roman decoration had a tendency to become profuse and over-elaborated. Whereas in Hellenic architecture every decorative detail was an intrinsic part of the structure, Roman decoration was something added after the structure was completed. It was, in effect, like clothing, fitted to the form of the body, and varying in design and sumptuousness according to the taste and purse of the wearer. Since architecture generally was an expression of pomp, pride, and power, it was inevitable that the richness of decoration should frequently run to extravagance.

To the lay-student, at least, the actual forms of Roman architecture are of less interest than the uses to which they were put. For the Roman genius was displayed in practicalness; in the resourcefulness with which it extended the scope of architecture to serve the necessities and ideals of life. Hence the temple-form has ceased to occupy the chief attention; the truly monumental character of Roman architecture is distributed over a variety of achievements of magnificence and utility.

Temple Plans.—The plan of the Roman temple was circular, polygonal, or rectangular; the last being the most usual type. The best preserved example is the so-called “Maison Carrée” at Nîmes in Provence, which was erected during the reign of Hadrian (A.D. 117-138). Its form is of the favourite kind: pseudo-peripteral, that is to say, the columns which surround the sides and end are not detached from but built into the walls of the cella. The portico has a deep projection, supported by ten detached columns. As usual in a Roman temple the stylobate is replaced by a podium, in this case about twelve feet high, which projects in front, enclosing the entrance steps. The columns are of the Corinthian order, 32 feet in height, supporting an entablature which measures 8 feet to the lower angles of the pediment. The frieze is bored with holes, in which it is supposed the letters of an inscription were fixed, and the cornice is richly decorated.

Another very interesting example at Nîmes is the so-called Temple of Diana, which probably was a nymphæum, or structure for flowers, statuary, and fountains, attached to some thermæ. The plan shows a central chamber, flanked by two passages; the exterior walls being devoid of columns. Meanwhile, the interior walls of the central chamber have a series of detached columns, supporting an entablature from which spring the curves of the barrel-vaulted ceiling. The outward thrust of the latter is offset by the continuous vaulting of the side-passages. It is probable, as we shall see, that this arrangement furnished a type for many of the Romanesque churches of Southern France.

Of the circular temples the best known examples are the Temple of Mater Matuta in Rome, the Temple of Vesta at Tivoli, and the Pantheon. Nothing but a few fragments remain of the Temple of Vesta in the Forum Romanum. The first named, situated in the Forum Boarium, is peripteral, consisting of a cylindrical cella, 28 feet in diameter surrounded by a circular colonnade of 20 Corinthian columns, 34 feet 7 inches high; the whole standing on a podium raised 6 feet from the ground. In the case of the Temple of Vesta at Tivoli the Corinthian columns, 18 in number, are 11 feet lower. “The reason for this difference,” writes Professor Banister-Fletcher, “is instructive. The Temple of Mater Matuta, placed in a low, flat situation, has columns of slender proportion in order to give it the required height; whereas the Tivoli example, placed on the edge of a rocky prominence and thus provided with a lofty basement, has columns of sturdier proportions.” A further difference is found in the foliage decoration of the capitals of the two temples; those of the Temple of Mater Matuta having pointed leaves of the Hellenic type of acanthus, while in the Temple of Tivoli the Roman type is adhered to.

The most famous circular example, as well as the most impressive of Roman temples to the modern mind, is the Pantheon. Investigation has proved that the circular part or Rotunda occupies the site of an earlier nymphæum, on the south side of which, in the reign of Augustus, B.C. 27, Agrippa erected a temple, consecrated to the Divinities of the Julian house under the name of Pantheum (“all-holy”). Hence the inscription on the frieze of the present portico: “M. Agrippa L. F. Cos. tertium fecit.” This temple, which, from Pliny’s account seems to have had a dome, was destroyed in the great fire in A.D. 80.

The present edifice was