Page:EB1911 - Volume 15.djvu/19

TOPOGRAPHY] depth of 1198 ft., while that of Como attains to 1365 ft. Of a wholly different character is the Lago di Varese, between the Lago Maggiore and that of Lugano, which is a mere shallow expanse of water, surrounded by hills of very moderate elevation. Two other small lakes in the same neighbourhood, as well as those of Erba and Pusiano, between Como and Lecco, are of a similar character.

The lakes of Central Italy, which are comparatively of trifling dimensions, belong to a wholly different class. The most important of these, the Lacus Fucinus of the ancients, now called the Lago di Celano, situated almost exactly in the centre of the peninsula, occupies a basin of considerable extent, surrounded by mountains and without any natural outlet, at an elevation of more than 2000 ft. Its waters have been in great part carried off by an artificial channel, and more than half its surface laid bare. Next in size is the Lago Trasimeno, a broad expanse of shallow waters, about 30 m. in circumference, surrounded by low hills. The neighbouring lake of Chiusi is of similar character, but much smaller dimensions. All the other lakes of Central Italy, which are scattered through the volcanic districts west of the Apennines, are of an entirely different formation, and occupy deep cup-shaped hollows, which have undoubtedly at one time formed the craters of extinct volcanoes. Such is the Lago di Bolsena, near the city of the same name, which is an extensive sheet of water, as well as the much smaller Lago di Vico (the Ciminian lake of ancient writers) and the Lago di Bracciano, nearer Rome, while to the south of Rome the well known lakes of Albano and Nemi have a similar origin.

The only lake properly so called in southern Italy is the Lago del Matese, in the heart of the mountain group of the same name, of small extent. The so-called lakes on the coast of the Adriatic north and south of the promontory of Gargano are brackish lagoons communicating with the sea.

The three great islands of Sicily, Sardinia and Corsica are closely connected with Italy, both by geographical position and community of language, but they are considered at length in separate articles. Of the smaller islands that lie near the coasts

of Italy, the most considerable is that of Elba, off the west coast of central Italy, about 50 m. S. of Leghorn, and separated from the mainland at Piombino by a strait of only about 6 m. in width. North of this, and about midway between Corsica and Tuscany, is the small island of Capraia, steep and rocky, and only 4 m. long, but with a secure port; Gorgona, about 25 m. farther north, is still smaller, and is a mere rock, inhabited by a few fishermen. South of Elba are the equally insignificant islets of Pianosa and Montecristo, while the more considerable island of Giglio lies much nearer the mainland, immediately opposite the mountain promontory of Monte Argentaro, itself almost an island. The islands farther south in the Tyrrhenian Sea are of an entirely different character. Of these Ischia and Procida, close to the northern headland of the Bay of Naples, are of volcanic origin, as is the case also with the more distant group of the Ponza Islands. These are three in number—Ponza, Palmarola and Zannone; while Ventotene (also of volcanic formation) is about midway between Ponza and Ischia. The island of Capri, on the other hand, opposite the southern promontory of the Bay of Naples, is a precipitous limestone rock. The Aeolian or Lipari Islands, a remarkable volcanic group, belong rather to Sicily than to Italy, though Stromboli, the most easterly of them, is about equidistant from Sicily and from the mainland.

The Italian coast of the Adriatic presents a great contrast to its opposite shores, for while the coast of Dalmatia is bordered by a succession of islands, great and small, the long and uniform coast-line of Italy from Otranto to Rimini presents not a single adjacent island; and the small outlying group of the Tremiti Islands (north of the Monte Gargano and about 15 m. from the mainland) alone breaks the monotony of this part of the Adriatic.

Geology.—The geology of Italy is mainly dependent upon that of the (q.v.). On each side of that great chain are found extensive Tertiary deposits, sometimes, as in Tuscany, the district of Monferrat, &c., forming a broken, hilly country, at others spreading into broad plains or undulating downs, such as the Tavoliere of Puglia, and the tract that forms the spur of Italy from Bari to Otranto.

Besides these, and leaving out of account the islands, the Italian peninsula presents four distinct volcanic districts. In three of them the volcanoes are entirely extinct, while the fourth is still in great activity.

1. The Euganean hills form a small group extending for about 10 m. from the neighbourhood of Padua to Este, and separated from the lower offshoots of the Alps by a portion of the wide plain of Padua. Monte Venda, their highest peak, is 1890 ft. high.

2. The Roman district, the largest of the four, extends from the hills of Albano to the frontier of Tuscany, and from the lower slopes of the Apennines to the Tyrrhenian Sea. It may be divided into three groups: the Monti Albani, the second highest of which, Monte Cavo (3115 ft.), is the ancient Mons Albanus, on the summit of which stood the temple of Jupiter Latialis, where the assemblies of the cities forming the Latin confederation were held; the Monti Cimini, which extend from the valley of the Tiber to the neighbourhood of Civita Vecchia, and attain at their culminating point an elevation of 3454 ft.; and the mountains of Radicofani and Monte Amiata, the latter of which is 5688 ft. high. The lakes of Bolsena (Vulsiniensis), of Bracciano (Sabatinus), of Vico (Ciminus), of Albano (Albanus), of Nemi (Nemorensis), and other smaller lakes belong to this district; while between its south-west extremity and Monte Circello the Pontine Marshes form a broad strip of alluvial soil infested by malaria.

3. The volcanic region of the Terra di Lavoro is separated by the Volscian mountains from the Roman district. It may be also divided into three groups. Of Roccamonfina, at the N.N.W. end of the Campanian Plain, the highest cone, called Montagna di Santa Croce, is 3291 ft. The Phlegraean Fields embrace all the country round Baiae and Pozzuoli and the adjoining islands. Monte Barbaro (Gaurus), north-east of the site of Cumae, Monte San Nicola (Epomeus), 2589 ft. in Ischia, and Camaldoli, 1488 ft., west of Naples, are the highest cones. The lakes Averno (Avernus), Lucrino (Lucrinus), Fusaro (Palus Acherusia), and Agnano are within this group, which has shown activity in historical times. A stream of lava issued in 1198 from the crater of the Solfatara, which still continues to exhale steam and noxious gases; the Lava dell’ Arso came out of the N.E. flank of Monte Epomeo in 1302; and Monte Nuovo, north-west of Pozzuoli (455 ft.), was thrown up in three days in September 1538. Since its first historical eruption in 79, Vesuvius or Somma, which forms the third group, has been in constant activity. The Punta del Nasone, the highest point of Somma, is 3714 ft. high, while the Punta del Palo, the highest point of the brim of the crater of Vesuvius, varies materially with successive eruptions from 3856 to 4275 ft.

4. The Apulian volcanic formation consists of the great mass of Monte Volture, which rises at the west end of the plains of Apulia, on the frontier of Basilicata, and is surrounded by the Apennines on its south-west and north-west sides. Its highest peak, the Pizzuto di Melfi, attains an elevation of 4365 ft. Within the widest crater there are the two small lakes of Monticchio and San Michele. In connexion with the volcanic districts we may mention Le Mofete, the pools of Ampsanctus, in a wooded valley S.E. of Frigento, in the province of Avellino, Campania (Virgil, Aeneid, vii. 563-571), The largest is not more than 160 ft. in circumference, and 7 ft. deep.

The whole of the great plain of Lombardy is covered by Pleistocene and recent deposits. It is a great depression—the continuation of the Adriatic Sea—filled up by deposits brought down by the rivers from the mountains. The depression was probably formed during the later stages of the growth of the Alps.

Climate and Vegetation.—The geographical position of Italy, extending from about 46° to 38° N., renders it one of the hottest countries in Europe. But the effect of its southern latitude is tempered by its peninsular character, bounded as it is on both sides by seas of considerable extent, as well as by the great range of the Alps with its snows and glaciers to the north. There are thus irregular variations of climate. Great differences also exist with regard to climate between northern and southern Italy, due in great part to other circumstances as well as to differences of latitude. Thus the great plain of northern Italy is chilled by the cold winds from the Alps, while the damp warm winds from the Mediterranean are to a great extent intercepted by the Ligurian Apennines. Hence this part of the country has a cold winter climate, so that while the mean summer temperature of Milan is higher than that of Sassari, and equal to that of Naples, and the extremes reached at Milan and Bologna are a good deal higher than those of Naples, the mean winter temperature of Turin is actually lower than that of Copenhagen. The lowest recorded winter temperature at Turin is 5° Fahr. Throughout the region north of the Apennines no plants will thrive which cannot stand occasional severe frosts in winter, so that not only oranges and lemons but even the olive tree cannot be grown, except in specially favoured situations. But the strip of coast between the Apennines and the sea, known as the Riviera of Genoa, is not only extremely favourable to the growth of olives, but produces oranges and lemons in abundance, while even the aloe, the cactus and the palm flourish in many places.

Central Italy also presents striking differences of climate and temperature according to the greater or less proximity to the mountains. Thus the greater part of Tuscany, and the provinces thence to Rome, enjoy a mild winter climate, and are well adapted to the growth of mulberries and olives as well as vines, but it is not till after passing Terracina, in proceeding along the western coast towards the south, that the vegetation of southern Italy develops in its full luxuriance. Even in the central parts of Tuscany, however, the climate is very much affected by the neighbouring mountains, and the increasing elevation of the Apennines as they proceed south produces a corresponding effect upon the temperature. But it is when we reach the central range of the Apennines that we find the coldest districts of Italy. In all the upland valleys of the Abruzzi snow begins to fall early in November, and heavy storms occur often as late as May; whole communities are shut out for months from any intercourse with their neighbours, and some villages are so long buried in snow that regular passages are made between the different houses for the sake of communication among the inhabitants. The district from the south-east of Lake Fucino to the Piano di Cinque Miglia, enclosing the upper basin of the Sangro