Page:Encyclopædia Britannica, Ninth Edition, v. 2.djvu/239

Rh AQUEDUCT 221 roof, supported on forty-eight pillars, and perforated to permit the escape of foul air. Tvo stairs lead by forty steps to the bottom of the reservoir. In the middle of the basin is a sinking to collect the deposit of the water. The walls and pillars are coated with a stucco so hard as to .resist a tool. The oversight of aqueducts was placed, in the times of the republic, under the sediles and censors, though the latter appear to have taken part in work of this kind rather from their financial interest in the matter. Under the empire this task devolved on special officials styled Curatores Aquarum. Among aqueducts outside of Italy, constructed in Roman times and existing still, the most remarkable, next to the Pont du Gard at Nismes already described, are (1.) The aqueduct bridges at Segovia and Tarragona in Spain, the former being 2400 feet long, with 159 arches of greatly admired masonry, in two tiers, and reaching the height of 102 feet. The bridge at Tarragona is 876 feet long, and 83 feet high. (2.) At Mayence are the ruins of an aqueduct 16,000 feet long, and carried on from 500 to 600 pillars. Similar witnesses of Roman occupation are to be seen in Dacia, Africa, and Greece. (3.) The aqueduct at Metz (figured on Plate IV.), which originally extended across the Moselle, here very broad, conveyed to the city an abundance of excellent water from Gorsa. From a large reservoir at the source of the aqueduct the water passed along subterranean channels built of hewn stone, and sufficiently spacious for a man to walk in them upright. Similar channels received the water after it had crossed the Moselle by this bridge, at the distance of about 6 miles from Metz, and conveyed it to the city. The bridge con sisted of only one row of arches. The middle arches have given way under the force of the river, but the others are still perfectly solid. (4.) On Plate III. is figured one of the principal bridges of the aqueduct of Antioch, 700 feet long, and at the deepest point 200 feet high. The lower part consists almost entirely of solid wall, and the upper part of a series of arches with very massive pillars. The masonry and design are rude. The water supply was drawn from several springs at a place called Battelma, about 4 or 5 miles from Antioch. From these separate springs the water was conducted by channels of hewn stone into a main channel, similarly constructed, which traversed the rest of the distance, being carried across streams and valleys by means of arches or bridges. (5.) At the village of Morea, about an hour s distance N.W. from the town of Mytilene, is the bridge of an aqueduct, figured on Plate III. The water-course is carried above massive pillars built of large hewn blocks of grey marble, and connected by means of three rows of arches, of which the uppermost is of brick. The bridge extended about 500 feet in length, and at the deepest was from 70 to 80 feet high. Judged by the masonry and the graceful design, it has been thought to be a work of the age of Augustus. Remains of this aqueduct are to be seen at Larisson Lamarousia, an hour s distance from Morea, and at St Demetri, two hours and a half from Ayasso, on the road to Vasilika. The aqueduct near Spoleto, which now serves also as a bridge, ia deserving of notice as an early instance of the use of the pointed arch, belonging as it does to the 7th or 8th century. It has ten arches, remarkable for the elegance of their design and the airy lightness of their proportions, each over 66 feet in span, and about 300 feet in height. (See Plate IV.) The aqueduct of Pyrgos, near Constantinople (figured on Plate III.), is a remarkable example of works of this class car ried out in the later times of the Roman empire. It consists of two branches, of which only one is seen in elevation on the plate. The other branch stood nearly #t right angles to this, and is seen partly on the plan. From this circum stance it was called the Bended or Crooked Aqueduct, to distinguish it from another termed the Long Aqueduct, situated near the source of the waters. The branch seen in elevation extends 670 feet in length, and is 106 feet in height at the deepest part. It is composed of three rows of arches, those in each row increasing in width from the bottom to the top an arrangement very properly intro duced with the view of saving materials without diminishing the strength of the work. The two upper rows consisted of arches of semicircles, the lower of Gothic arches ; and this circumstance serves to fix the date of the structure, as these last were not introduced until the 10th century. The breadth of the building at the base was 21 feet, and it diminished with a regular batter on each side to the top, where it was only 11 feet. The base also was protected by strong buttresses or counterforts, erected against each of the pillars. The other branch of the aqueduct was 300 feet long, and consisted of twelve semicircular arches. This aqueduct serves to convey to Constantinople the waters of the valley of Belgrade, one of the principal sources from which the city is supplied. These are situated on the heights of Mount Hsemus, the extremity of the Balkan Mountains, which overhangs the Black Sea. The water rises about 15 miles from the city, and between 3 and 4 miles west of the village of Belgrade, in three sources, which run in three deep and very confined valleys. These unite a little below the village, and then are collected into a large reservoir. After flowing a mile or two from this reservoir, the waters are augmented by two other streams, and conveyed by a channel of stone to the Crooked Aqueduct. From this they are conveyed to another which is the Long Aqueduct ; and then, with various accessions, into a third, termed the Aqueduct of Justinian. From this they enter a vaulted conduit, which skirts the hills on the left side. of the valley, and crosses a broad valley 2 miles below the Aqueduct of Justinian, by means of an aqueduct, with a double row of arcades of a very beautiful construction. The conduit then proceeds onward in a circuitous route, till it reaches the reservoir of Egri Kapan, situated just without and on the walls of the city. From this the water is conducted to the various quarters of the city, and also to the reservoir of St Sophia, which supplies the seraglio of the grand signior. The Long Aqueduct is more imposing by its extent than the Crooked one, but is far inferior in the regularity of design and disposition of the materials. It is evidently a work of the Turks. It consists of two rows of arcades, the lower being forty-eight in number, and the upper fifty. The whole length was about 2200 feet, and the height 80 feet. The Aqueduct of Justinian is a very excellent work, and without doubt one of the finest monuments which remain to us of the Middle Ages. It consists of two rows of large arcades in the pointed style, with four arches in each. Those of the lower story have 52 feet of span, the upper ones 40 feet. The piers are supported by strong buttresses, and at different heights they have little arches passing through them, which relieve the deadness of the solid pillar. The length of this aqueduct is 720 feet, and the height 109 feet. This aqueduct, though it bears the name of Justinian, Avas probably erected in the time of Constantine. Besides the waters of Belgrade, Constantinople was supplied from several other principal sources, one of which took its rise on the heights of the same mountains, 3 or 4 miles east of Belgrade. This was conveyed in a similar manner by an arched channel, elevated, when it was necessary, on aqueduct bridges, till it reached the northern parts of the city. It was in the course of this aqueduct that the contrivance of the souterasi or hydraulic obelisks, described by Andreossy (in his voyage to the Black Sea and account of the Thracian Bosphorus) was