Page:Encyclopædia Britannica, Ninth Edition, v. 13.djvu/454

436 ITALY the lake at its south-eastern extremity at Lecco, and lias thence a cour.se through the plain of above 70 miles till it enters the Po between Piacenza and Cremona. In this part of its course it flows by Lodi and Pizzighettone, and receives the waters of two minor but considerable streams, the Brembo, descending from the Val Brembana, and the Sario from the Val Seriana above Bergamo. The Oglio, a more considerable stream than either of the last two, rises in the Monte Tonale above Edolo, and descends through the Val Camonica to Lovere, where it expands into a large lake, called the Lake of Iseo from the town of that name on its southern shore. Issuing from thence at its south west extremity, the Oglio has a long and winding course through the plain before it finally reaches the Po a few miles above Borgoforte. In this lower part of its course it receives the smaller streams of the Mella, which flows by Brescia, and the Chiese, which proceeds from a small lake called the Lago d Idro, between the Like of Iseo and that of Garda. The last of the great tributaries of the Po is the Mincio, which flows from the Lago di Garda, the largest of all the Italian lakes, and has a course of about 40 miles from Peschiera, where it issues from the lake at its south-eastern angle, till its joins the Po. About 12 miles above the confluence it passes under the walls of Mantua, and expands into a broad lake-like reach so as entirely to encircle that city. Notwithstanding its extent, the Lake of Garda is not fed, like those of Como and Maggiore, by the snows of the high Alps, nor is the stream which enters it at its northern extremity (at Riva) commonly known as the Mincio, though in reality forming the main source of that river, but is termed the Sarca ; it rises at the foot of the Monte Tonale. The Adige, which is formed by the junction of two streams the Etsch or Adige proper and the Eisach, both of which belong to Tyrol rather than to Italy descends as far as Verona, where it enters the great plain, with a course from north to south nearly parallel to the rivers last described, and would seem likely in like manner to dis charge its waters into those of the Po, but below Legnago it turns to the eastward and pursues a course parallel to that of the Po itself for a space of about 40 miles, till it enters the Adriatic by an independent mouth about 8 miles from the northern outlet of the greater stream. The waters of the two rivers have, however, been made to communicate by artificial cuts and canals in more than one place. The Po itself, which is here a very large stream, with an average width of from 400 to GOO yards, con tinues to flow with an undivided mass of waters as far as a place called Sta Maria di Ariano, where it parts into two arms, known as the Po della Maestra and Po di Goro, and these again are subdivided into several other branches, forming an extensive delta above 20 miles in width from north to south. The point of bifurcation is at present about 25 miles from the sea, but was formerly much farther inland, more than 10 miles west of Ferrara, where a small arm of the river, still called the Po di Ferrara, branches off from the main stream. Previous to the year 1154 this channel was the main stream, and the two small branches into which it subdivides, called the Po di Volano and Po di Primaro, were in early times the two main out lets of the great river. The southernmost of these, the Po di Primaro, enters the Adriatic only about 12 miles north of Ravenna, so that if these two arms bo included, the whole delta of the Po extends through a space of about 36 miles from south to north. The whole course of the river, including its windings, is estimated at about 450 miles. Besides the delta of the Po and the large marshy tracts which it forms, there exist on both sides of it extensive lagoons of salt water, generally separated from the Adriatic [GEOGRAPHY, by narrow strips of sand or embankments, partly natural partly artificial, but having openings from distance to dis tance through these barriers, which admit of the influx and efflux of the sea-water, and serve as ports for communica tion with the mainland. The best known and the most extensive of these lagoons is that in which Venice is situated, and which extends from Torcello in the north to Chioggia and Brondolo in the south, a distance of above 40 miles ; but they were formerly much more extensive, and afforded a continuous means of internal navigation, by what were called " the Seven Seas " (Septem Maria), from Ravenna to Altinum, a few miles north of Torcello. That city, like Ravenna, originally stood in the midst of a lagoon ; and the coast to the east of it, the whole way to near Monfalcone, where it meets the mountains, is occupied by similar expanses of water, which are, however, continually drying up and becoming gradually converted into dry land. The changes in the coast-line have conse quently been considerable throughout this extent. The tract in the interior, adjoining this long line of lagoons, is, like the basin of the Po, a broad expanse of perfectly level alluvial plain, extending from the Adige eastwards to the Carnic Alps, where they approach close to the Adriatic between Aquileia and Trieste, and north wards to the foot of the greit chain, which here sweeps round in a semicircle from the neighbourhood of Vicenza to that of Aquileia. The space thus included was known in ancient times as Venetia,a name applied in the Middle Ages to the well-known city ; the eastern portion of it became known in the Middle Ages as the Frioul or Friuli. It is traversed by a number of rivers, descending from the Alpine chain ; but these are for the most part nothing more than mountain torrents, bringing down vast masses of stones and shingle to the plain below. Beginning from the Adige and proceeding from west to east the streams worthy of notice are (1) the Brenta, a navigable stream of a different character from the rest, which descends from the Val Sugana, and passes within a few miles of Padua ; (2) the Piave, flowing by Belluno ; (3) the Tagliamento, which descends from the Carnic Alps above Tolmezzo, and though a large stream has a very torrent-like character; (4) the Isonzo, a deep and rapid river, which has its sources in the highest group of the Julian Alps, at the foot of Mont Terglon, and brings with it the waters of the Natisone, also a considerable stream. Returning to the south of the Po, the tributaries of that river on its right bank below the Tanaro are very inferior. in volume and importance to those from the north. Flowing from the Ligurian Apennines, which are of no great elevation and never attain to the limit of perpetual snow, they have no continuous supply through the year, and in summer generally dwindle into insignificant streams flowing through dry beds of shingle. Beginning from the Tanaro, the principal of them are (1) the Scrivia, a small but rapid stream flowing from the Apennines at the back of Genoa ; (2) the Trebbia, a much larger river, though of the same torrent-like character, which rises near Torriglia within 20 miles of Genoa, flows by Bobbio, and joins the Po a few miles above Piacenza ; (3) the Nure, a few miles east of the preceding ; (4) the Taro, a more considerable stream; (5) the Parma, flowing by the city of the same name; (6) the Enza; (7) the Secchia, which flows by Modena ; (8) the Panaro, a few miles to the east of that city ; (9) the Reno, which flows by Bologna, but instead of holding its course till it discharges its waters into the Po, is turned aside by an artificial channel into the Po di Primaro. The other small streams east of this of which the most considerable are the Solaro, the Santerno, flowing by Imola, the Lamone by Faenza, the Montone by Forli all have their outlet in like manner into the Po di