The Roman emperors were far from confining their attention to the water supply of ltome Bade for numerous and gigantic works of that description, for the supply of important provincial towns, were executed by their orders. [Aquamucv.] During the decline of the lower empire, even, the construction of aqueducts and of reservoirs was carried on with the tame degree of energy as in the brighter periods of the Roman rule; and the neighbourhood of Constantinople possesses ruins of the aqueduct of Justinian, end in the valley of Bourgas, which may rival any of the earlier structures in magnitude at least. if not in oonstructive skill. Perhaps the most remarkable parts of the water-works of Constanti nople were, however, the subterranean reservoirs there constructed to store the water. One of them is about 319,200 cubic feet in capacity, and the other about 1,023,970 cubic feet, and they are vaulted throughout.
Of course the art of distributing water suffered under the effects of the irruption of the barbarians ; and all that was done by even the most enlightened of the rulers of the Gothic, Vandalic, and Lombardia tribes was to repair and maintain the aqueducts they found to be in existence when they overran the provinces of the Roman empire. There is a tradition connecting the erection of the aqueduct of Spo leto with the name of Theoderic the Goth ; but the style of the monument, and many other indications it furnishes, would throw great doubts on the correctness of the story ; nor can we discover auy authentic records of the execution of any great works for the supply of water to towns during the mediteval period. until about the end of the 18th century. In fact, the great centres of population in modern times were but very insignificant villages in the early periods of his tory ; and property was held by far too uncertain a tenure to justify the execution of great public works. The Italian cities seem to have been the first to attempt anything like a systematic distribution of water ; and 3lichael lloceanegra at Genoa, in 1278, the unknown authors of the Spoleto and of the bivita Castellana aqueducts, at other periods in the 5liddlo Ages, revived the modes of construction adopted by the Romans. In the north of Europe there du not appear to have been made any attempts to rival the gorgeous monuments of the Roman empire ; and in nearly all caaes—as at London and at Paria—the system adopted seems principally to have been to lead to some stone reservoirs the waters of springs rising in the country, by means of wooden or of leaden pipes. When the populations of those towns had lye' cased to
a considerable extent, it was found, however, that, as in the former case of Rome, it was no longer possible to obtain the necessary quantity of water front the superficial gravels, or from the water bearing strata around them ; and we accordingly find that at the close of the ineclimval period efforts were made to secure water-supplies to the large towns from larger areas than had previously sufficed. In France, the engineers seem to have considered themselves bound to return to the traditions of the Romans, and the aqueduct of Arccuil was built in avowed imitation of the analogous structures of the ancients Iu England, the system of contouring tbo hills by open water-courses prevailed ; and the Plymouth Lcct, established by Sir F. Drake, and the New River by Sir H. Myddclton, may be cited as illustrations of the system long adopted here. The great aqueduct of Lisbon, erected betweeu 1713 and 1732; the aqueduct of Caserta, erected by Venvitclii about 1753 ; the aqueduct of Symeto, erected by Prince Ifiecari, in Sicily ; the Croton Aqueduct, and the Roqucfavour Aqueduct, may be referred to as illustrations of the modern execution of works for the supply of water, designed upon the principles of the ancients ; but the majority of the modern water-supplies are executed In a far leas ostentatious manner, and with modifications required by the local habits or by the municipal organisation of the towns them selves. Of late years, also, the improvements which have been effected in the machinery used for the purpoaa of raising water, and the new applications of metallurgy to the building arts, have so profoundly changed the economical conditions of the distribution of water, that it is hardly possible to compare the systems which have respectively pre vailed in ancient or in very modern times.. The fundamental difference seems, however, to consist in this, namely, that the state melte took the execution of the water supplies of antiquity, whilst in modern times they have been left entirely to municipalities or to private industry. What the moderns may have gained in economy under these circumstances, they have lost in art; and just precisely as the economical element of the calculation prevails, so does the manner in which a modern water supply is effected lose all character of beauty as a monument.