Of the 25·15 miles of river dealt with by the French, only 3·14 miles were rendered navigable. The remainder of the main course adapted for navigation consisted of four portions of canal, in all 17 miles in length. In addition there were 1·25 mile of short canals, connecting the main course with the Mosel. Corresponding to the canals there are four movable weirs in the Mosel at Custines, Marbache, Dieulouard, and Pont-à-Mousson, which maintain the necessary water-level in dry seasons. The fall from the Rhine-Marne Canal at Frouard to the Mosel system is 26·25 feet, and the fall from Frouard to Amaville is 48·6 feet, overcome by six locks. The cost of these 20 miles of navigable channel is stated by the French engineers to have been 208,000_l_. The German works recently executed include a continuation of the main canal from Arnaville to Novéant, where it debouches into the Mosel for a length of 1·05 mile; the canalisation of the Mosel itself thence to Jouy-aux-Arches, 3·38 miles long, where a movable weir maintains the water-level in this reach; and a main canal thence to Metz on the right bank of the river, 5·55 miles long. The branch canals are comparatively independent of the above. One of them is situated on the left bank at Ars, and consists of a rectification of a side channel of the river, 2·54 miles long, intended solely for the use of the iron foundries of that town; a feeder of this, being on low-lying ground, requires special protective embankments. The other, 1258 yards long, connects the main canal with a basin at the railway terminus at Metz. The portion of the Mosel from the embouchure of the Ars branch canal down to the island of Vaux is made into a navigable basin for the use of the foundries, a movable weir at the latter place giving the necessary increased depth of water. _The Rhine and Danube Canal._—In 1834 an elaborate report was made by C. T. Kleinschrod, of Munich, relative to the feasibility of constructing a canal to connect the Rhine and the Danube.[71] The proposal was to proceed from the Rhine by way of the Main as far as Bamberg, and there commence a canal which should proceed by Nüremberg to Keeheim, where it would effect a junction with the Danube. The total length of the artificial waterway between these two points, Bamberg and Keeheim, was stated at 23⅓ German miles. The writer of the pamphlet made an elaborate estimate of the probable cost of the undertaking, which had the support of the King of Bavaria, and it was demonstrated that at that time, when there were hardly any railways in Germany, it would be attended with a great economy of transport. Owing, however, to the competition of railways, and the extent to which they soon afterwards met the requirements of the country, the project was not entirely successful. The canal was completed in 1844. It is 110 miles long and 7 feet deep.