Fig. 95.—THE PONTINE MARSHES.
Scale 1 : 280,000.
In order to drain these marshes an accumulation of difficulties will have to be surmounted. A range of wooded dunes bounds the marshes on the west. Having crossed these, we enter a second zone of marshes, which are separated from the sea by a second range of dunes, extending northward from the Monte Circello, and likewise densely wooded. These two formidable barriers would have to be surmounted in order to drain the marshes towards the west. Nor are the prospects more promising in the direction of Terracina, for there, too, every outlet is stopped by dunes. The streams and canals crossing the marshes are, moreover, choked up with a dense {267} growth of aquatic plants, which impedes the circulation of the water, feeble though it be. Herds of buffaloes are sometimes driven into these streams to trample down the vegetation, but neither this barbarous procedure nor the more regular process of mowing has availed against its rapid and luxuriant growth, and the water remains stagnant. Rains are not only heavy in this portion of Italy, but the superabundant waters of neighbouring river basins actually find their way through subterranean channels into the depression occupied by the Pontine Marshes. This happens after heavy rains in the case of the Sacco, a tributary of the Garigliano, and of the Teverone, a tributary of the Tiber, and to this circumstance {268} must be ascribed the curious fact first ascertained by M. de Prony, viz. that the volume of water annually discharged by the Badino, which drains the marshes, exceeds by one-half the whole of the rain which annually descends upon them. When this happens the whole of the country is under water. Another danger arises during dry weather. It happens then occasionally that the parched vegetation is ignited through the carelessness of herdsmen; the fire communicates itself to the turfy soil, and the latter smoulders until the subsoil water is reached. In this manner tracts of land which were looked upon as secure against every inundation are converted into marsh. During the greater portion of the year the Pontine Marshes present the appearance of a plain covered with herbage and flowers, and it is matter for surprise that a country so fertile should be without inhabitants. The town of Ninfa, which was built in the eleventh century, near the northern extremity of the plain, has since been abandoned, its walls, houses, and palaces still remaining, covered with ivy and other creeping plants.
There can be no doubt that our engineers would be able to reclaim this desolate region. The system adopted in the case of the valley of the Chiana may not be practicable, but other, if more costly, means may be devised. Whatever the outlay, it is sure to be productive, for even now the marshes yield rich harvests of wheat and maize.
The Tiber, or Tevere, the great river of the Romans, has defied all attempts at correction down to our own days, and its sudden floods are said to be even more formidable now than they were in the days of the Republic. Ever since the time of Ancus Martius there has been going on a struggle against the alluvium brought down by the river, and it will need all the skill of the Italian engineers to master this difficult problem.
The Tiber is by far the most important river of the peninsular portion of Italy, and its basin is the most extensive.[90] It is, too, the only river that is navigable in its lower course, from Ostia to Fidenæ. The Tiber rises on the western slope of the Alpe della Luna, in the latitude of Florence. The valley through which it flows, whilst in the heart of the Apennines, is of surpassing beauty; at one time it expands into broad and fertile basins, at others it is hemmed in by precipitous rocks. Below the charming basin of Perugia the Tiber receives the Topino, formed by the confluence of several streams in the old lacustrine basin of Foligno, one of the most delightful districts of all Italy, situated at the foot of the Great Apennines and of the Col Fiorito, which leads across them. The Clituno (Clitumnus) debouches upon this plain, famous on account of its pellucid waters:—
“The most living crystal that was e’er
The haunt of the river nymph, to gaze and lave