When the Romans used the Doric at all, they used a base for the column, which was never done at Athens.  They also altered the Doric capital, which cannot be improved.  Again, most of the Grecian Doric temples were peripteral,—­surrounded with pillars on all the sides.  But the Romans built with porticos on one front only, which had a greater projection than the Grecian.  They generally were projected three columns, while the Greek portico had usually but a single row.  Many of the Roman temples are circular, like the Pantheon, which has a portico of eight columns projected to the depth of three.  Nor did the Romans construct hypaethral or uncovered temples with internal columns, like the Greeks.  The Pantheon is an exception, since the dome has an open eye; and one great ornament of this beautiful structure is in the arrangement of internal columns placed in the front of niches, composed of antae, or pier-formed ends of walls, to carry an entablature round under an attic on which the cupola rests.  The Romans also adopted coupled columns, broken and recessed entablatures, and pedestals, which are considered blemishes.  They again paid more attention to the interior than to the exterior decoration of their palaces and baths,—­as we may infer from the ruins of Hadrian’s villa at Tivoli and the excavations of Pompeii.

The pediments (roof-angles) used in Roman architectural works are steeper than those made by the Greeks, varying in inclination from eighteen to twenty-five degrees, instead of fourteen.  The mouldings are the same as the Grecian in general form, although they differ from them in contour; they are less delicate and graceful, but were used in great profusion.  Roman architecture is overdone with ornament, every moulding carved, and every straight surface sculptured with foliage or historical subjects in relief.  The ornaments of the frieze consist of foliage and animals, with a variety of other things.  The great exuberance of ornament is considered a defect, although when applied to some structures it is exceedingly beautiful.  In the time of the first Caesars Roman architecture had, from the huge size of the buildings, a character of grandeur and magnificence.  Columns and arches appeared in all the leading public buildings,—­columns generally forming the external and arches the internal construction.  Fabric after fabric arose on the ruins of others.  The Flavii supplanted the edifices of Nero, which ministered to debauchery, by structures of public utility.

The Romans invented no new principle in architecture, unless it be the arch, which was known, though not practically applied, by the Assyrians, Egyptians, and Greeks.  The Romans were a practical and utilitarian people, and needed for their various structures greater economy of material than was compatible with large blocks of stone, especially for such as were carried to great altitudes.  The arch supplied this want, and is perhaps the greatest invention ever made in