_The Marne Canal._—The original canal was constructed between the years 1838 and 1853. It commences by a junction with the Upper Marne Canal at Vitry le Français, and terminates by a junction with the river Ill and the Rhine Canal, near Strasburg, thus connecting the valleys of the Seine and the Rhine, and also the intervening rivers, which include the Maas, Moselle, Soar, &c. Its length between Vitry and Strasburg is 193½ miles, and it crosses the four watersheds dividing the catchment basins of the Marne, Maas, Moselle, Soar, and Rhine; there are, however, only two summit reaches, as the divides between the Maas and Moselle, and the Soar and the Rhine, are tunnelled through at Fory and Arzweiler, respectively. There are altogether five tunnels, with a total length of 5½ miles. The level of the water above the sea is, at Vitry, 332·62 feet; at the Mauvages summit tunnel, through the Marne-Maas divide, 922·75 feet; at Nancy, 648·10 feet; at the Vosges summit level, 873·93 feet; and at Strasburg, 444·18 feet. There are 177 locks on the canal, and the mean rise of each is 8·60 feet. Some years since it was contemplated to increase the water supply, but the improvements were delayed by the Franco-German war, which resulted in a transfer to Germany of the Alsatian portion of the canal, and also of one of the most important sources of supply, viz. the river Soar. To render the system independent of this latter portion, in 1874 the construction of the East Canal was authorised. This commences at Givet, on the Belgian frontier, joins the Rhine-Marne Canal at Troussey, and again leaving the latter canal at Toul, follows the course of the Upper Moselle to Epinal, where it branches off in a south-westerly direction to its termination at Port-sur-Saône. The depth of water in this canal was fixed at 6 feet 6 inches. The Rhine-Marne Canal had originally a depth of 5 feet 3 inches, a bottom breadth of 32 feet 10 inches, and sides sloped at 1½ to 1. This depth has been increased to 6 feet 6 inches, the canal bed has been cleaned and lined with concrete 6½ inches to 8½ inches thick, where necessary, and the headways of the bridges and tunnels has been raised to 12 feet 2 inches above the new water-level. Through the Mauvages tunnel a chain has been laid, and all the traffic is worked by two chain steam-tugs with fireless boilers (Francq’s patent). The most important of the new works are those for the additional supply of water. They comprise pumping-stations at Pierre-la-Treiche and Valcourt, near Toul, at both of which the pumps are actuated by turbines, and a steam-pumping station at Vacon, as well as ducts for conveying the water from the pumping-stations to the canal, and an impounding reservoir at Paroy. Gallons. The total amount of water required annually for the Rhine-Marne canal is 1,364,620,000