Those who suppose that the object of the aqueduct was to conduct water to the amphitheatre only, instead of being appropriated to the domestic uses of the inhabitants, have not regarded with attention the peculiarities of its construction. The simplicity and unornamented style of its archi- tecture, perfect, however, in its proportions, and just in every point of its design, marks the very character of these works of Agrippa. The waters about the colony of Neman- sis, from the disturbed state of the springs in winter and spring, from the muddied flow of the torrents in times of flood, and the deficiency in times of drought and summer, were precarious, unhealthy, and insufficient; a colony so placed would be left very imperfect, nay, defective, without the means of obtaining salubrious water ; accordingly, we find an aqueduct and fountain at Nismes, bringing a constant and copious supply, unmixed with any of the streams or rivers that might spoil it. To avoid this^it was brought from the mountains, excluding all communication with the waters of the country through which it passed, and where it became necessary to pass the deep valley in which the river Garden runs, it was conducted across that valley by a bridge of two stages of arcades, at a height of 150 feet above the ordinary level of the river, that is, measuring to the top of the second range of arcades, which perfected Agrippa's erection, the water being conducted on the top of the second arcade. The third story, part of which is now remaining, raised upon a range of arcades, has been thought to be a building of a very different age from the two main ranges, in its materials, in its structure, and proportions ; and even in the placing of its parts, it does not correspond with the old original bridge on which it was erected. The style of the architecture is also said to be very different, and very inferior to the rest. Although an adventitious addition, it is clearly Roman work, probably of a much later age. The length of this aqueduct, as far as discovered, is about six French leagues, or 15 miles, in a direction resembling a horse-shoe, and derives its water from the spring of Eure, and Airau, near the village of Uzes. The Pont du Garde is in the middle of its course ; the greater part of the ancient line can now be traced, and much of what remains is in a fine state of preservation. The observation made with regard to the parts of the aqueducts of Rome which were under ground, being in the best state of repair, applies with still greater force to the aqueduct at Nismes, the subterranean parts being even now in perfect preservation. The line was carried along the sides of the 8 30 PRELIMINARY ESSAY. hills, which were occasionally perforated to shorten the distance, and, where necessary, .the lesser valleys were crossed by the erection of small bridges, or arcades, preserving the level of the aqueducts. The greater portion of the excavated part has been cut through the stone strata of which the hills are composed, in some places at a distance of about 13 feet beneath the surface. The Pont du Garde, is that part of the aqueduct of Nismes which traverses the deep valley in which runs the Garden or Garde, between the mountains near Vers and St. Bennet. This part, considered even alone, is one of the grandest erections made by the Romans in Gaul. The first row of arcades, beneath which runs the Gardon, is com- posed of six arches ; the second row has eleven arches, and the third range has thirty- fire. All these arches are semi-circular, springing from piers, more or less high ; it was upon the third range that the water channel was formed according to some antiquaries. According to the measurement of a French engineer, the height of this aqueduct bridge is about 157 feet above the low water level of the river. Its length on the level of the moulding terminating the first range of arcades, is 561 feet, and 876 feet on the level of the moulding terminating the second story. The total height, according to the same author, is 161 feet ; namely, 66 feet for the first range, 66 feet for the second range, and 21J feet for the third range to the top of the flags covering the water channel ; the width of the bridge is 21 feet at the first range, 16 feet on the second, 10 feet on the third ; this forms a considerable offset on each stage ; the five piers of the first range of arcades were formed with salient angles or bees. The division of the arches