as the single river Tiber."* Dionysius, surnamed Periegetes, who lived about 300 years after Christ, and wrote a description of the world in Greek Hexameters, calls it "most regal of rivers;" and Claudian, writing a century later, anticipates a time "when the Rhine shall be lined, after the fashion of the 'Tiber, with mansions pleasing to the eye." The moderns, who know the Tiber only as a river winding through the desolate Campagna, or skirted by mean and dirty buildings in its passage through the town, may smile at the epithet of regal which the poet bestows upon it. But the word merely expresses the effect produced upon his imagination by the lordly mansions and richly-decorated villas, between which the Tiber flowed, suggesting to his thoughts the power and opulence of regal Rome. At that time the river was but a subordinate feature in the scene, lost, as it were, in the crowd of its accessories, and forming, like the Roman "girl of the period," described by Ovid, "the smallest part of itself."|| It appears from this that the Romans had succeeded in imparting an ornamental character to their river, and rendering its borders an eligible site for country houses. For this purpose they must have removed the mud as soon as the inundations subsided, and paid constant attention to the condition of the banks; which then, perhaps, ascended in gentle slopes from the river, or were cut into terraces, and planted with ornamental shrubs. It seems that the Romans had taken their river for better and for worse, and resolved to turn its capabilities, whether for use or ornament, to the best account; though as Tacitus informs us, they had abandoned all hope of regulating the volume of its waters. We, too, shall fail, I am convinced, in our attempts to prevent its inundations; but *Pluribus prope solus quam cæteri in omnibus terris amnes accolitur, aspiciturque villis.—Plin. III. (9), 54, Teub. † Θύμβρις εϋῤῥειτης ποταμών βασιλεύτατος ἄλλων [“ Dionysii Alexandrini TηS ÓLKOVμÉVNS TEρinynois. Line 353, Lutetiæ, MDXLVII."] et sævum gentibus amnem. Tibridis in morem domibus prævalet amoenis.-De laudibus Stiliconis. || Pars minima est ipsa puella sui.-Ovid. Rem. Am. 344. we may, as I shall hereafter shew, foresee both the height o the floods, and the time of their occurrence, and place ou moveable property out of reach of damage. We may also like the Romans, speedily repair the mischief it has done, and obliterate the traces it has left behind. Though we canno persuade ourselves that its colour is a beauty, we may prevent the river from continuing to be an eye-sore, and set it off like a plain woman, by a becoming dress. The banks of the Tiber may again be lined with the villas of the citizens, and stately mansions once more be reflected in the waters of the fine reaches which extend above the Ponte Molle. I will now give a description of the Tiber and its tributaries, and notice the most remarkable inundations which have occurred in ancient or modern times. I will then proceed to examine the theories which have been propounded to account for these inundations, and the schemes which have been devised to prevent their recurrence. Most of these, as I shall attempt to shew are based upon false assumptions, or conceived in ignorance of the first principles of science. They must, therefore, result in failure, and in the loss of the money expended, whether by private speculators or the state. DESCRIPTION OF THE TIBER. Though the Tiber is insignificant in size compared with the great rivers of the world, it is one of the most famous, and even its tributaries, down to the smallest brook, have some historical or poetic association connected with them, or exhibit some singular natural peculiarity. Its stream is swelled by the superfluous waters of the historic Thrasymene; its affluents, the Velino and the Anio, form the celebrated cascades of Terni and Tivoli; the Clitumnus and the Nar are invested with poetic interest by the verses of Virgil, Ovid, and Silius Italicus; while the Chiana presents the singular phenomenon of a river which, within the historic period, has divided itself into two, and now forms a connecting link between the Arno and the Tiber, discharging a portion of its waters into each. The smaller streams, also, the Cremera, the Allia, and the Almo, have each their legend, historical, or mythological; while the rivulet of the Aqua Crabra, or Marrana, recalls the memory of Cicero and his litigation with the company which supplied his establishment at Tusculum with water from the brook. The Tiber rises nearly due east of Florence, and on the opposite side of the ridge which gives birth to the Arno. It issues in a copious spring of limpid water, which at the distance of a mile has force enough to turn a mill. If we are to believe Bacci, it exhales so warm a vapour that snow, notwithstanding the elevation of the region, will not lie along its course within half a mile. For a distance of fiftysix miles it flows in a south-easterly direction through an elevated valley, in the upper part of which the cold, according to Pliny the younger, who had a villa there, was too great for the olive, and where the snow often accumulates to a considerable depth. Not far from Perugia it turns to the south, wh with Verra ulla loxa down by the windings of this ***Alt, 1/809 la fm divent the Chascia, which bangs with it the Topno (endently Tines, and the waters of the Carrie Currumts, known to the readers of Virgil,* Properties. d and fiber İnous as the river on whose banks were bred, and in whose stream were washed, the milk-white oxen "whicht drew the Roman triumphs to the temples of the gods," and the same which is so picturesquely described by the youngere Miny. At a place called le Vene, one of the sources of the Clitumnus rises at the foot of a hill. Like the fountain of Vaucluse, it issues a small river from the earth, and, according to Pliny, had sufficient depth of water to float a boat. It is clear as crystal, delightfully cool in summer, and of an agreeable warmth in winter. Near it stands a temple once sacred to the river god, but now surmounted by the triumphant Cross, It seems to have been a favorite place of resort for the Romans, as far as their limited means of locomotion would permit; since even the ferocious Caligula, as Suetonius tells us, attended by his body-guard of Batavians, was among the visitors to these celebrated springs. The beauty of the scenery appears to have been the attraction; for there were no mineral sources, and a refined superstition would have prevented the Romans from availing themselves of the agreeable temperature of the water to indulge in the luxury of bathing, rivers near their sources being accounted sacred, and polluted by the contact of a naked body. Of all the misdeeds of Nero none, perhaps, contributed more to his unpopularity than his swimming, during one of his drunken Hine albi, Clitumne, greges, et maxima taurus Romanos ad templa Deum duxere triumphos.-Vir. Geo. II. 146. + Qua formosa suo Clitumnus flumina luco, Integit, et niveos abluit unda boves.-Pro. II. 19. * Et lavat ingentem pertundens flumine sacro Chitumnus taurum.-Sil, Ital. VIII, 516. J Pầm. vn. Fp, &, Suet. Cal. 4N Jack An Xon, 22. frolics, in the source of the Aqua Marcia, the same which is brought by the aqueduct to Rome, and which rises in the mountains of the Abruzzi, where Nero was staying at the tirne. When the news of this act of profanation arrived in the city it created a great sensation, and an illness with which he was shortly afterwards seized was attributed to the anger of the god. Seven miles lower down on the right the Tiber receives the Nestore, a large and impetuous torrent, or torrentaccio, as it is called by the Italians. The Nestore, where it enters the Tiber, flows in a bed of sand and shingle no less than a third of a Roman mile in width,* and after heavy rains must bring down an enormous body of water. Into the Cina, one of its tributaries, by means of a tunnel, the overflow of the lake of Thrasymene is discharged. The emissary originates in the south eastern bay of the lake, but when, or by whom, the work was executed is matter of dispute. Thirty and a half miles further on, the Tiber is joined by the Chiana (anciently Clanis), which, after uniting with the Paglia, flows into it on the same side as the Nestore, and in the neighbourhood of Orvieto. The Paglia rises in the high volcanic mountain of Monte Amiata, and in summer is nearly dry; but its broad stony channel at Acquapendente shows what a contribution it must bring to the main stream in time of floods. The Chiana, which from the black and muddy colour of its waters has received the name of the Lethe of Tuscany, but which might with more propriety be called the Tuscan Cocytus, was once a single stream originating in the neighbourhood of Arezzo, and flowing southward into the Tiber. But in the middle ages a large portion of the valley in which it flowed was filled up by the debris which in time of floods was brought down by the lateral torrents. A sort of plateau was thus formed, sloping at its edges towards the vallies of the Tiber and the Arno. *Gambarini and Chiesa. |