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The great nave consists of but four bays, and it is not, says Mr. Fergusson, too much to assert that if the church had been planned by the Gothic architects of the thirteenth or fourteenth century, it would have seemed from one-third to one-half larger than at present. So, he remarks, that the apparent size of the Colosseum would have been nearly one-half less if the exterior had been formed by a single storey, and each arch had been the height of the entire edifice, and the span of four of the arches which were actually employed. It is, he points out, the line of arch beyond arch in its horizontal circumference, and of arch upon arch in its vertical elevation, which lead on the mind and invest the Flavian amphitheatre with its air of grandeur. The entablatures diminish the impression. Their broad shelves interrupt the upward view and take from the seeming loftiness of the structure. The architect had but an imperfect appreciation of what was best in his own design, and the similar incongruities which prevail throughout the buildings of the Romans is absolute proof that the failing was national. They were always putting together heterogeneous elements, and were insensible to the vices of the discordant composition. Their colossal works are more striking in ruin than when seen in their integrity. Devastation and decay have softened the harsher features of the Colosseum, and the imagination fills up the blanks with visions of magnificence which the complete amphitheatre would have gone far to destroy.
Mr. Pugin drew a happy distinction between constructed ornament and ornamented construction. The Grecian temple is an exemplification of the second. The columns and the entablature, though rendered exquisite by form, sculpture, and painting, were not the less the very substance of the fabric, and to remove them would be to pull down the temple itself. The columns and entablature of the Colosseum are an instance, on the other hand, of constructed ornament. They were erected for show, and might have been stripped from the face of the wall without affecting its stability. As mere decoration they are too massive, and to be justified they should either have been mechanically essential, or the outward indication of the true structural plan. The one merit which the entablatures of the Colosseum possess—that they stretch round the building, as Mr. Fergusson observes, 'in long vanishing lines of the most graceful curvature'-would have been preserved without the accompanying defects if architrave, frieze, and cornice had been remodelled to suit their new application. Immediately within the external wall of the amphitheatre were storeys of corridors, with staircases leading to those above, that the throng of people might have easy access at different levels to the long slope of benches
. The storeys inside were rightly Vol. 120.-No. 240.
marked on the exterior, which should always be in keeping with the internal arrangement, and for this purpose the entablatures should have been reduced to string-courses. The columns should have been omitted. The piers did the duty, and the suitable decoration was not an extraneous column but an ornamented pier. Fitness was by no means the aim of the architect. As the Greek orders were famed for beauty, he was the slave of the idea that they must be beautiful when attached to his Etruscan shell.
The Romans applied their curvilinear forms to roofing in masonry, and became bold constructors of the dome. Their principal temples were the rectangular temples of Greece, varied more or less in details; but, as some of the Etruscan temples were round, the Romans likewise used the circular form, which culminated in the Pantheon. The body of the building and the portico are of different dates. An inscription on the frieze of the portico states that it was erected by Agrippa in his third Consulship, or B.C. 27, and below this is a second inscription, which records that the edifice was restored by the Emperors Septimius Severus and Caracalla, when it was decayed by age. Mr. Fergusson is satisfied from the evidence of style that the restoration was a reconstruction, that the portico alone is of the time of Augustus, and that the rotunda cannot be placed earlier than between the accession of Severus, A.D. 193, and the death of Caracalla, A.D. 217. The Pantheon illustrates an increasing tendency of Roman architecture. The temple of the Egyptians, distinct from its avenues of Sphinxes and its colossal statues, was calculated rather for inside than outside effect. The exterior was simple, and appealed to the eye by its surface decorations more than by architectural design. The relative merits of inside and out were reversed by the Greeks, and their interiors could not compare with their elevations. The Romans showed a disposition to revert to the earlier plan, and Mr. Fergusson remarks that in many of their later buildings the adornments were chiefly within. In spite of the monumental character of the Pantheon, its external diameter of 183 feet 8 inches, and its height of 108 feet, exclusive of the dome, the elevation is plain to baldness. The rotunda is merely girt by a first, second, and third cornice, which divide the bare and windowless wall into belts or storeys. The rectangular Corinthian portico is said by Mr. Fergusson “to be the finest which Rome exhibits.' It is 103 feet wide, and the sixteen columns, 47 feet high, have their shafts formed of a single piece of granite. This appendage, beautiful in itself, does not assimilate with the central building, and, instead of relieving the nakedness, renders it more conspicuous by contrast. There is no attempt at amalgamation. The cornice of the portico is not joined to any of the cornices of the rotunda, but
dies into the wall at a different level, as if the object had been to destroy every semblance of unity. Neither are the parts in proportion. The circular mass overpowers the portico, which is altogether a patch. The whole elevation is thoroughly Roman. There is a grand idea so crudely worked out that the temple has the aspect of a first rough sketch before the architect had made any effort to clothe it with dignity and grace.
The inside of the Pantheon far surpasses the exterior. The span of the hemispherical dome is 145 feet 6 inches, which is a few feet more than the dome of St. Peter's, and its height is 147 feet. The top is not closed, but has a circular opening 28 feet 6 inches in diameter; and this lofty central void, looking up to the sky, is the single means by which light is admitted. Between the ribs of the dome are tiers of sunk panels, of which the largest are 12 feet square, and these hollows answer the double end of adorning the roof, and diminishing its weight. Mr. Fergusson ranks the interior among the sublimest inside views in the world; and adds, that the one great eye opening upon heaven is by far the noblest conception for lighting a building to be found in Europe.' The sublimity would have been much increased but for the old delusion of the Roman architect that the best decoration for the shell was to line it with columns and entablatures. The construction of the cylinder or drum which supports the dome may be seen from the woodcut. There are sixteen huge piers, which are coupled on the inner circumference, with only a niche on the face to mark the division. The double piers are alternated within the building by oblong or semicircular recesses, and these have arched heads which transmit the pressure of the dome to the adjoining blocks of wall. The mechanical expedients for securing strength without waste of material are good, but they are masked and falsified by the decoration. The columns and pilasters that stand round the drum bear an entablature which crosses piers and recesses in the middle, and
Plan of Pantheon at Rome. Scale 100 ft. to 1 in. obscures the plan. Above the entablature is a storey of panels to carry on the disguise, and this is crowned by a second cornice at the springing of the 2 1 2
dome. The anomaly of introducing into a covered interior two rows of a contrivance for throwing off water from the wall is the smallest defect of the design. The immense dome appears to crush the drum ; and the entablature - which, in fact, has little work to perform-seems inadequate to support its share of the superstructure. If the actual mechanism had been displayed ; if the vast blocks of masonry which divide the recesses had been shown in their unbroken solidity, without being cut up and concealed by an incongruous coating ; if the dome had been seen to rest upon the broad and deep vertical props, without the deceptive suggestion that it was upborne by the horizontal entablature, the cylinder would have looked fully equal to its office, and the massive piers would have been fit companions to the roof they sustain. The true construction was well adapted for architectural effect, and it was a strange obliquity of taste to hide it under a comparatively feeble frontage of unmeaning ornament. The real and apparent construction are identical in the dome, and its solid simplicity shames the superficial delusive casing on the drum below.
A commoner form of roofing than the dome was the vault, which is one of the especial distinctions of Roman architecture. A cylindrical vault was an extension of the semicircular arch, and the discovery of the last involved the first. If a secure arch could be built which measured three feet from front to rear, it was obvious that a second length of three feet could be added, and that this repetition might go on without end. Six hundred years before the Christian era Rome possessed in its cloaca maxima, or great sewer, a subterranean vault of the most durable construction. It was about 14 feet in diameter, which would have covered a narrow room, but was useless for spanning the great public buildings of the Romans. By degrees they took courage, and acquired the art of bridging over enormous spaces from the tops of lofty walls. In their partiality for the plan they sometimes substituted it for the time-hallowed Greek wooden roof of their temples. There is an instance in a ruin at Nîmes. The temple was modified to ensure the stability of the vault
. The exterior is without columns except in the portico. A couple of longitudinal walls inside divide the area into three breadths. The central aisle, which is the loftiest, and 27 feet wide, carries a ribbed cylindrical or tunnel vault, which runs from end to end. The side aisles have similar but smaller tunnels, of 71 feet diameter, and these abut on the partition walls against the spring of the middle vault, counterbalance its thrust in part, and link the strain to the substantial wall of the exterior. The method was correct, but almost self-evident, and had a drawback which rendered it inapplicable to edifices of great
dimensions. If the smaller vaults were to abut directly against the central vault and resist its thrust, the walls of the nave could not be carried up to form a clerestory, and the body of the building would be insufficiently lighted. The Romans set to work to conquer the difficulty in their gigantic basilicas and baths, and met with brilliant success. The basilica of Maxentius, which dates between A.D. 306 and 312, will furnish an idea of their system in its zenith.
The basilica was at once a court of justice and an exchange. A portico in the Maxentian example ran along the whole of one
Plan of Basilica of Maxentius. Scale 100 ft. to 1 in.
end, and there was a second portico on one of the sides. In each of the opposite walls was a semicircular projection or apse, which faced the principal entrances and was far more effective than a common square termination. There was a platform at the back of the apse approached by a semicircular range of steps, and in the centre of the raised circumference was the chair of the magistrate, who was separated by the recess from the noise and bustle of dealers and gossips. The steps on his right hand and on his left were occupied by the persons engaged in a cause. An altar stood in front of the apse, and here sacrifices were performed as a prelude to public business of importance. The edifice was on a scale of imperial magnificence, and the area, roofed in a single span, was enormous, The nave of Westminster Abbey is 34 feet