| Excavation | 695,000 cubic metres. |
| Bricks | 2,000,000. |
| Dressed stone | 3000 cubic metres. |
| Stone for revetment | 3000 square metres. |
| Lime | 3500 tons. |
| Oak piles | 2200. |
| Oak sheet piles | 8100 square metres. |
| Ironwork | 39,780 kilos. |
The width of the canal, which is 40 metres wide at the commencement, is gradually lessened until it reaches the aqueduct over the Dora Baltea near the 10th kilometre of its course, when its width becomes 20 metres. The sides, when not protected by retaining walls, have an inclination of 45°. Crossing the valley of the Dora, which is about 2 kilometres in width, on a high embankment, and the actual bed of the same river, by means of an aqueduct consisting of nine arches of 16 metres span each, the canal takes a north-easterly direction nearly parallel to the railway from Turin to Milan, which it crosses near the station of San Germano. At the 40th kilometre the canal passes in syphon under the torrent Elvo. This syphon is built in brickwork, and consists of five elliptical openings, 5 metres in width and 2·30 metres in height.
The next work of importance is the embankment and aqueduct over the torrent Cervo, and differs but little from that over the Dora. The most important work on the whole canal, with the exception of the headworks, is the syphon for passing underneath the torrent Sesia. It is similar in section to that previously described for the Elvo, but considerably longer, and is probably one of the largest works of this class in Italy.
The next works in importance are the aqueducts for crossing the torrents Roasenda and Marchiazza, and syphons under the torrents Agogna and Terdoppio, near Novara. The width of the canal up to the 62nd kilometre is 20 metres, and as, at this point, a considerable quantity of water is introduced from it into the Roggia, Busca and Rizzo-Biraga, the canal is reduced to 12·50 metres in width to the 74th kilometre, when its section is again reduced, and after passing under the Terdoppio—at which point the new branch canal “Quintino Sella” is derived—its width is only 7·50 metres. The fall of the canal between the headworks at Chivasso and the Dora Baltea varies from 0·50 to 0·25 in 1000, and over the remainder—with the exception of aqueducts and syphons, when in some cases it is greater—the gradient is 0·25 per 1000. The total fall is 21·73. Besides the works just described, 480 of less importance, consisting of bridges for roads, aqueducts, syphons for the passage of existing water-courses and canals of irrigation, watchhouses, &c., were constructed.
The River Po.—The Po, which takes its rise at Mont Viso, crosses the whole plain of Upper Piedmont, a plain formed of a deep alluvial soil, very fertile, and well cultivated. Passing through territory of Turin, it receives the drainage of the rich meadows, as also the sewage of that town, and before reaching Chivasso it receives the rivers Dora Riparia, Stura, Orco, and Malone. The waters of the Po in floods are dense with rich alluvial matter, of the fertilising properties of which evident proofs may be observed throughout the course of this river. After great floods, as if by magic, bare shoals of gravel become covered with a deep strata of alluvial soil, on which the seeds of trees and shrubs carried down by the waters soon take root, and in a very short time they are covered with a luxuriant vegetation. The waters of the Po on this account are highly valued for irrigation, as also from the fact of its temperature being higher than that of its tributaries. The fertilising properties of this water are now fully appreciated in Lomellina, where large tracts of land which were formerly bare and arid wastes, are now converted into rich meadows and rice fields, through the agency of the waters which have been brought to bear upon them by the Canal Cavour, already alluded to.
Even in the Vercellese, where the want of water is not so much felt, the waters of the Po, introduced into the existing canals, and mingling with those of the Dora, tend to modify the extreme coldness of the latter river, due to its origin in the glaciers of the Val d’Aosta and the siliceous-magnesian sands that its waters contain in suspension. It is, therefore, with just pride that Italians have named the Po the “Nile of Italy.”
Although the Po is the only extensive river basin in Italy, there are many other rivers in that country that are more or less navigable, some of them inclined to the Tyrrhenian Sea, and some to the Ionian Sea, but most of them, including the Po, to the Adriatic.
Projected Canals.—Among the proposals recently put forward for extending, by artificial means, the commerce and navigation of Italy, one of the most important is designed to provide for the construction of a ship canal to connect the Tyrrhenian Sea, and the Adriatic, near Fano and Castro. The distance to be traversed by this canal would be 175 miles, and the cost has been estimated at about 20 millions sterling. It is claimed that the proposed canal would be of great advantage to the navigation between the east and the west coasts of the Peninsula.
In 1889 a company was formed in London for the purpose of establishing a system of canal, lake, and river navigation in the north of Italy. This company expects to carry a very large share of the traffic at lower rates than those quoted by the railways.
FOOTNOTES
CHAPTER XII