whence the access to it is by a flight of steps downwards, through an arch in a brick wall, still partially covered with stucco. It has been conjectured with probability, that the entrances to it were occasionally closed, from the remains of iron gates having been found at some of them. A smaller passage occurs to the right of the arch just mentioned, and a fountain attached to the wall between them. A is supposed to have been a temple of Venus; B, a public granary; C, a temple of Jupiter; D, probably a Senaculum, or council chamber; E, a temple to Mercury; F, a Chalcidicum; G G, curiæ; H, treasury; 1. triumphal arch; K, aræostyle portico with ambulatory above.

220. Triumphal Arches.-The Romans were the first people who erected triumphal arches; their earliest examples being extremely simple and plain. A plain arch with a statue of the victor and his trophies on the summit, was for a long period the only method practised. The arch by degrees expanded in after times, the style became enriched, and the whole was at length loaded with a profusion of every sort of ornament. Latterly they were a rectangular mass (see fig. 124. of the arch of Constantine), penetrated by three arches, a central and two smaller side ones. The upper part consisted of a very high attic, frequently covered with inscriptions and bas reliefs, statues, triumphal cars and ornaments of that kind. The keystones were sometimes decorated with figures of victory. Of the triumphal arches that remain there are three classes: first, those consisting of a single arch, as the arch of Trajan at Ancona, and Titus at Rome; second, those in which there are two arches, as in the example at Verona; third, those with three arches, whereof the central was the principal one, and those at the sides much smaller, as the arches of Constantine, Septimius Severus, &c. The most ancient of the remaining arches is that of Augustus at Rimini. It was erected on the occasion of his repairing the Flaminian way from that town to Rome. The erection of these triumphal arches afforded the means of gratifying the extraordinary vanity of the people with whom they originated. Many of them are in very bad taste; a remark that applies even to the Arch of Titus, which was erected before the arts had more than begun to droop. (See figs. in Book III.) The orders applied to them are unnecessary to be described in detail, because inapplicable except under precisely similar circumstances. 221. Bridges. There is perhaps no single point in the history of architecture by which the civilisation of a people is so easily recognised as by that of their bridges. Latterly, in this country, the division of science as well as labour has so changed, that it seems almost necessary to refer to other works for knowledge on this subject; but as this is one in which architecture in all its branches must be considered, we shall here, as in the other sections of this work relating to the point in question, treat it in such manner as to give the reader some notion of the subject. The history of the bridges in every nation is connected with local causes, which have great influence on their construction; and though in other respects a nation may in the arts have attained a high pitch of excellence, yet it is possible that in bridge building their progress may be very limited as respects science. The matter

will depend entirely on the nature of the country. In our view of Grecian Architecture this subject has not been even mentioned. and it is nearly certain that Greece boasts uo

bridge whose date is anterior to its occupation by the Romans. But, independent of its want of acquaintance with the arch, the circumstance may be accounted for by the country not being intersected by any river of magnitude. Those to which one might be inclined to attach the naine of river, are rather mountain torrents than sheets of water rolling their streams down to the ocean. A single arch in most cases would be all that was necessary to connect opposite banks, and the rocks themselves would form abutments for the single arch that was to connect them, without danger of failure.

222. In Italy, however, a country watered by many and considerable rivers, the study of the architecture of bridges was indispensable, as well for the accommodation of the cities with which it abounded, as for the service of the constant military expeditions of the restless and craving people who inhabited its surface. From its very earliest foundation, no city in the world would sooner have been placed in the predicament of requiring bridges than Rome herself; besides which, skill was required in their construction over a river like the Tiber, rapid and liable to be swelled by sudden floods. The earliest bridges of the Romans were of timber such was that which joined the Janiculum to the Mons Aventinus, called the Pons Sublicius from the sublicæ, stakes (Liv. i. c. 33.), whereof it was composed. It is not here our intention to enumerate the ancient bridges of Rome; but the ruins of those which have come under our observation exhibit skill and science not inferior to the most extraordinary examples which modern art can exhibit; witness the Pons Narniensis on the Flaminian way near Narni, about sixty miles from Rome. It was built by Augustus, and at the present day there remains, as though standing to mock modern science, an arch of a span of 150 ft., whose intrados is 100 ft. above the level of the river below. But of the works of this kind executed by the Romans we know of none, either in ancient or modern times, that is comparable with that erected by Trajan over the Danube, whose piers from their foun dation were 150 ft. in height, and the span of whose arches was 170 ft., and to the number of twenty. The bridge was 60 ft. in width. This work, whose existence is scarcely credible, putting in the background all that of which in the present day it is our habit to boast, is reputed to have been destroyed by Hadrian, the successor of its founder, under a pretence that if the barbarians becaine masters of it, it might serve them as well

for making incursions on the empire, as for the empire in repressing those incursions. But other less creditable motives have been attributed to Hadrian for its destruction, one of them the envy he had of the name of its founder. There are still partial remains of an ancient Roman bridge over the Tagus near Alcantara. This consisted of six arches, each 30 ft. span, extending altogether 800 ft. in length, and some of them 200 ft. high above the river. We do not, in closing our brief view of the bridges of the Romans, more than mention the extraordinary temporary bridge which Cæsar threw over the Rhine.

223. Aqueducts. It is obvious that of all the requisites for a city, the supply of wholesome water is only equalled by that of discharging it, which latter we have before seen was well provided for in the Eternal City. The aqueducts by which the Romans supplied their cities with this necessary element, are among the largest and most magnificent of their works. Their ruins alone, without other testimony, supply the means of estimating their extraordinary power, skill, and industry. They are works which sink into nothingness all other remnants of antiquity, not even excluding the amphitheatres. which we shall soon have to notice, because they were for the comfort, not the pastime, of the people. The earliest aqueduct was that of Appius Claudius, which we have above noticed as constructed in the 442d year of the city. It conveyed the Aqua Appia to Rome, froin a distance of between seven and eight miles, by a deep subterraneous channel upwards of eleven miles in length. We shall here digress for a moment, by observing that upon the discovery of good water at a distance from the city at a much higher level than the service therein indicated, it was the practice to supply by means of a channel raised at any height as the case needed, through a stone-formed trough raised on the tops of arches as the course of it required over valleys, and otherwise became necessary from the nature of the face of the country, such a quantity as the source would afford. Hence the arcades raised to carry this simple trough of supply were often of stupendous height, and their length was no less surprising. In the present day, the power of steam has afforded other means of supplying a great city with water; but we much question whether the supply afforded by all the concealed pipes of this vast metropolis can compete in refreshment and general utility to its inhabitants with those at the present day poured into Rome, without becoming a burthen to the respective inhabitants, and this principally from the means which their predecessors provided.

224. The aqueduct of Quintus Martius, erected 312 years before Christ, is among the most extraordinary of the Roman aqueducts. Commencing at a spring thirty-three miles distant from Rome, it made a circuit of three miles, and then, after being conveyed through a vault or tunnel of 16 ft. in diameter, continued for thirty-eight miles along a series of arcades 70 ft. in height. It was formed with three distinct channels, one above the other, conveying the water from three different sources. In the upper one was the Aqua Julia, in the next the Aqua Tepula, and in the lowest the Aqua Martia. The Aqua Virginia was constructed by Agrippa, and in its course passed through a tunnel 800 paces in length. The Aqua Claudia, begun by Nero, and finished by Claudius, of which fig. 125.

shows several arches, conveyed water to Rome from a distance of thirty-eight miles; thirty miles of this length was subterraneous, and seven miles on arcades, and it still affords a supply of water to the city. The Anio was conveyed to Rome by two different channels: the first was carried over a length of forty-three miles, and the latter of sixty-three, whereof six

miles and a half formed a continued series of arches, many of them upwards of 100 ft. in height above the ground on which they stood. At the beginning of the reign of Nerva, there were nine great aqueducts at Rome. That emperor, under the superintendence of Julius Frontinus, constructed five others, and at a later period there were as many as twenty. According to Frontinus (de Aquæductibus) the nine earlier aqueducts supplied 14,018 quinaria daily, which are equal to 27,743,100 cubic ft. ; and it has been computed that when all the aqueducts were in delivery, the surprising quantity of 50,000,000 of cubic ft. of water was afforded to the inhabitants of Rome, so that, reckoning the population at one million, which it probably never exceeded, 50 cubic ft. of water were allowed for the consumption of each inhabitant. More magnificent Roman aqueducts are, however, to be found in the provinces than those that supplied the city. That of Metz, whereof many of the arcades remain, is one of the most remarkable; extending across the Moselle, a river of considerable breadth where it crosses it, it conveyed the water of the Gorse to the city of Metz. From the reservoir in which the water was received, it was conducted through subterranean channels of hewn stone, so spacious that in them a man might stand upright. The arches appear to have been about fifty in number, and about 50 ft. in height. Those in the middle of the river have been swept away by the ice, those at the extremities remaining entire. In a still more perfect state than that at Metz is the aqueduct of Segovia.

of which one hundred and fifty of the arches remain. all formed of large blocks unconnected by cement, in two ranks of arcades one above the other.

925. It has been conjectured that the causes for not carrying these aqueducts in straight lines were first to avoid excessive height, where low grounds were crossed, and, secondly, to diminish the velocity of the water, so that it might not be delivered to the city in a turbid state. Along the line of an aqueduct, according to Montfauçon, at certain intervals, reservoirs called Castella were formed, in which the water might deposit its silt; these were round towers of masonry raised of course as high as the aqueduct itself, and sometimes highly ornamented. The same author observes that below the general bed of the channel, pits were sunk for the reception and deposit of the earthy particles which the water contained. Vitruvius directs the channels to be covered over to protect the water from the sun's rays, and (lib. viii. chap. 7.) he moreover directs that when water-pipes are passed across a valley, a venter should be formed, which is a subterranean reservoir wherein the water may be collected, and by which its expansion may be diminished, so that the hydrostatical pressure will not burst the joints. He also recommends that open vertical pipes should be raised for the escape of the air which accompanies the water, a practice which the moderns have found it necessary to adopt wherever it is necessary to bend pipes upwards, and thus permit the escape of air, which would impede, and even stop altogether, the movement of the water in them. (Some additional details are given in the GLOSSARY.)

226. Theatres.-The earliest stone theatre of Rome, as we have before stated (185.), was that of l'ompey; but it must be recollected that as there are notices in history of this theatre having been more than once consumed by fire, there can be little doubt that a portion, probably the seats and scenes, were of wood. The second theatre of stone was raised by Julius Caesar, after which Augustus reared one in honour of Marcellus, the son of his sister. The scanty ruins of this last enable one to do little more than trace its elevation, and from their curve to compute its extent. There was no essential difference between the form of the Roman and Greek Theatre, of which latter we have given a diagram in fig. 106. We nevertheless think it right here to present the reader with one of the Roman Theatre fig. 126.), as nearly as it can be made out from the description of Vitruvius. (Book v.

Chap. 6. "The form of a theatre," according to that author," is to be adjusted so, that from the centre of the dimension allotted to the base of the perimeter, a circle is to be described, in

which are inscribed, at equal distances from each other, four equilateral triangles whose points must touch the circumference of the circle."" Of these triangles the side of that which is nearest the scene determines the face of it, in that part where it cuts the circumference of the circle. A line drawn parallel to it through the centre

will separate the pulpitum of the proscenium from the orchestra. Thus the pulpitum becomes more spacious and convenient that that of the Greeks, because our actors remain chiefly on the scena. In the orchestra are assigned seats to the senators: the height of its pulpitum must not exceed 5 ft., so that the spectators in the orchestra may have a clear view of the motions of the actors. The portions between the staircases (cunei) of the theatre are to be so divided that the vertices of the triangles, that touch the circumference, may point to the directions of the ascents and steps between the cunei on the first præcinction or story. Above these the steps are placed alternately and form the upper cunei in the middle of those below. The angles thus pointing to staircases will be seven in number, and the remaining five will indicate certain points on the scene. That in the centre, for instance, is the situation for the royal door, those on the right and left the doors of the guests, and those at the extremities the points at which the road diverges. The seats (gradus) for the spectators are not to be less than 20 in. in height nor more than 22. Their width is not to be more than 24 ft. nor less than 2 ft." Besides the theatres named, that of Cornelius Balbus, built by him in honour of Augustus, was on a scale of considerable magnificence.

227. The large theatre at Pompeii, as was frequently the case, was formed upon the slope of a hill, the corridor being the highest part, whence the audience descended to their seats, and staircases were saved. The gradus at this theatre were about 1 ft. 3 in. high, and 2 ft. 4 in. wide, and from a part which is divided and numbered off, 1 ft. 3 in. appear to have been allotted to each spectator. There still remain some of the iron rings, for the reception of the masts from which the velarium or awning was suspended.

228. Amphitheatres. The amphitheatre was unknown to the Greeks. At an early period, however, in Rome, human beings were compelled to fight for the amusement of spectators. The taste for such spectacles increased with its indulgence; but it was nevertheless not

beasts still remain; one at Capua; another at Verona; a very fine one at Pola in Istria (fig. 127.). In France, Arles, Saintes, Autun, Nismes, and Nice possessed amphitheatres. In short, wherever the Romans went, they erected those extraordinary monuments of their power and skill. But all that we have enumerated were far surpassed by the Coliseum, which has been already briefly mentioned by us at page 79. The form of this building on the plan is an ellipse, whose transverse exterior axis is 615 ft. and its conjugate 510 ft., covering therefore nearly six English acres of ground. The whole mass is placed on an ascent of six stages, which encircle its whole circumference. In the centre is the arena, a name which it received from being strewed with sand, the transverse and conjugate axes whereof are 281 and 176 ft. respectively. Round the arena was a wall on which was the podium or fence; and immediately behind this wall all round was a row of cells in which the beasts were placed preparatory to their entrance into the arena. In the rear of the cells was a corridor from which vaults radiated in directions perpendicular or nearly so to the curve of the ellipse, and serving to support the first manianum or interior range of seats. In some of these vaults were steps leading to the podium; others were merely passages between the first corridor and the next towards the interior. The second corridor was lighted by apertures cut through its vault to the præcinctio which separated the first and second horizontal division of the seats. In rear of the second corridor, vaults again radiated, in some whereof were steps leading to the second division of the seats, and in others were galleries which led from the corridor to the double arcade, surrounding the whole edifice. The description will be better comprehended by reference to figs. 128. and 129., in the latter whereof a portion of the exterior side is removed, to exhibit the section.

229. About the whole exterior of the building, there are three orders of columns rising above each other, and one of pilasters crowning the whole. The columns are of equal diameter, and are filled in between with eighty arcades in each story. The arches of these arcades have all archivolt mouldings round them. Four of the arcades in the lower tier were reserved for the admission of distinguished personages, the remainder for the populace: these last were called vomitoria, serving both for ingress and egress to and from the places of the spectators, by means of steps under the vaults that supported the seats. The piers which support the arches are 7 ft. 4. in. wide; on each is a half column projecting from the general face of the wall. The opening between the piers is 17 ft. 38 in. Impost mouldings are placed at the springing of the arches, and encircle the building except where interrupted by the columns and openings. The lower order resembles the Doric, except that the frieze is without triglyphs and the cornice without mutules. Desgodetz makes the height of the columns 27 63 ft., and their lower diameter 2 91 ft. Their diminution is very small. The height of the entablature is 6.64 ft., and the height, therefore, of the whole order above the pavement is 34-27 ft. The second order is Ionic, and stands on a dado 6 ft. high, broken under the columns to receive their projection from the wall. The columns are 25-73 ft. high. The volutes of the capitals are without ornament; the eye being merely marked by a circle. The entablature is 6.64 ft. high, and its subdivisions are like that in the order below. There are neither modillions nor dentils in the cornice. The height of the whole order is 38:37 ft. The third order is Corinthian, standing on a dado 6.39 ft. high. The columns are 25.58 ft. high, the entablature 6.59 ft., and the height of the entire order, including the dado, is 38 57 ft.