It is probable that the arch was invent ed in Greece, but was almost constantly employed by the Romans, who not only considered it necessary in the construc tion, but as an ornament, which they la vishly employed in the apertures of walls, and in the ceilings over passages and apartments of their buildings. Particu larly In the decline of the empire, from the reign of Constantine, and upon the establishment of Christianity, external magnificence was every where sacrificed to internal decoration. The purity of taste in the arts of design declined rapid ly, and finally perished with the extinc tion of the empire. The most beautiful edifices, erected in the preceding reigns, were divested of their ornaments, to de corate the churches. In this age of spo liation, architects, deficient in the know ledge of their professions, adopted the most ready modes of construction : to ac complish this, many beautiful structures were deprived of their columns, and placed at wide intervals in the new build ings; and over the capitals were thrown arches for the support of the superstruc ture : most of the ornamental parts were taken from other buildings, which were spoiled for the purpose. The edifices of Italy now assumed the same general fea tures as those which characterised the middle ages. This disposition is the plan of the Roman basilicas, but is more near ly allied, in the elevation, to the opposite sides of the Egyptian oeci, which has also the same plan as the basilica, and which was of similar construction to the churches in after times, excepting in the want of arches : both had a nave, with an aisle upon each flank, separated from the nave by a range of columns, which supported a wall, pierced with windows for lighting the nave : against this wall, and over the columns, were placed other attached co lumns. This, when roofed over with a groined sealing, such as that of the Tem ple of Peace, will form the interior of a building similar to that of the Saxon churches.
The Corinthian order was the favourite order among the Romans, and, as far as existing examples enable us to judge, the only order well understood, and happily executed.
What we now call the Composite order is of Roman extraction : it was employed in many of their buildings, but chiefly in the triumphal arches: from what we find in Vitruvius, it was never accounted a dis tinct order, but as a species of the Co rinthian only. The only existing exam ple that Rome affords, of the Doric order, is that executed in the theatre of Marseilles, and, though in the age of Augustus, is hut a vitiated composition : the columns are meagre and plain, divested of that sublime grandeur and elegance which are so conspicuous in the solidity and flutings of the Grecian Doric. The dentils in the cornice are too effeminate a substitute for the masculine mutules, which are so cha racteristic of the origin of this order.
The Ionic in the same building is ill executed. The Channels of the volutes, of the capitals, of the Ionic columns on the Coliseum, and the lentil band of the cor nice, are not cut. The Ionic order of the Temple of Fortune, though it has been held out as a model, is ill proportioned, and the spirals of the volutes are un gracefully formed. The ionic of the
Temple of Concord is out of character, the volutes arc insignificantly small, and mutules supply the place of (lentils in the cornice. The Romans placed one order upon another, on the exterior, in the se veral stories of some of their buildings ; but the Greeks only employed them around the cells of their temples, forming a peristyle.
The Romans carried the method of ce mentitious buildings ,to the utmost degree of perfection. Their most considerable edifices had the facings of their walls, and the arches and angles of brick, or small rubble stones squared ; the cores built with pebble and rubble stones, grouted or run with liquid mortar ; and at regular internals were strengthened with courses of bond stones. This construction of wails was frequently stuccoed, or incrust ed with marble. It is much more expe ditious and economical than that built of wrought stone, which occasions a greater waste of materials and loss of time. The durability and solidity of the Roman ce mentitious buildings is such, that mortar has acquired a hardness superior to the stones which are connected by it. This, when compared with the fragility and crumbling nature of the mortar used by modern builders, had led some to suppose that the ancients possessed processes in the making of cements, which have, from the lapse of time, been lost to the present day. But the information and experi ments of ingenious men have exploded this opinion ; and there is no doubt, that, if proper attention be paid to the choice of limestone and sand, to the burning of the lime, and above all, that care he taken in the mixing and tempering these mate rials, workmen will be enabled to rival those of Rome. This has been tried in some instances, though the lapse of ages maybe necessary to make the comparison complete ; however, it will appear, from the following account of Vitruvius, that the method of making lime by the Ro mans was not very different from what it is at the present day. " Lime should be burnt from white stone, or flint, of which the thick and hard sort are more proper for building walls, as those which are po-, roils are for plastering. When the lime is burnt, the ingredients are thus to be mixed : with three parts of pit sand, one part of lime is to be mingled; but if river or sea sand is used, two parts of sand and one of lime must be united; for in these proportions the mortar will have a proper consistence ; if bricks, or tiles, pounded, and sifted, be joined with river or pit sand, to the quantity of a third part, it will make the mortar stronger and fitter for use." The works of wrought stone of the Ro. mans, as well as those of the Greeks, were constructed without cement ; but cramps and ligatures of iron and bronze were used in great abundance. The use of metal was not confined to cramps and bolts, for they eVen constructed roofs of bronze, which was also used in magnifi cent profusion in the decorations of build ings. It excites regret, to reflect that the means employed by the ancients to increase the beauty, and ensure the du ration of their edifices, have only, in ma ny instances, served to accelerate their destruction.