The western part of this system is the river Elbe, na vigable from the frontiets of Bohemia : At Leutmeritz it carries small boats ; at Perna, above Dresden, it ad mits river barges ; from Perna to Hamburg it has an un obstructed navigation of upwards of 300 miles ; and 70 miles lower it falls into the North Sea. Of its branches, the Havel is the only one worthy of notice ; it rises on the borders of Mecklenburg, runs southwards to Span dau—near Berlin it receives the Spree, when it becomes navigable for vessels of considerable burthen; from Spandau it passes to Potsdam and Brandenburgh, into the Elbe at Haveiburgh. To improve this river, in 1743-5, Frederick II. caused the following woilts to be constructed.
1. The canal of Plauen, from the Lake of Plau at the bend of the Havel near Brandenburgh directly to the Elbe, by which the navigation to Magdeburgh is short ened 76 miles. The canai is only 17 miles long; the fall to the Elbe is 23 feet ; by three locks ; the width is 26 feet. The engineer was Mahistre.
2. lite canal of Potsdam—a cut to shorten the navi gation of the Havel.
3. 'rite canal of Finaw, from the upper part of the Havel, 20 miles north of Berlin, to the Oder at Oders burg. It is 23 miles long, falling 130 fcct, by 13 locks. It was begun in 1605, but was only completed in 1751.
4. The INIuhlrose canal front the Spree to the Oder. This was the earliest in Prussia, having been finished its 1688, with I() locks of wood. The engineer was Phi lip de Chiese. The locks were afterwards reduced to 8, and built with stone by king Frederick 1. It is 23 miles in length ; it ascends 10 feet, hy one lock, to the summit levol, and from it, descends 64 feet, by 7 locks, into the Oder, live miles above Frankfort ; the width is 60 feet, depth 11 feet.
The Oder is navigable from the Baltic to Brieg in Silesia, above Brcslaw, being about 300 miles. At Kus trin it receives the Warta front Poland. 13elow that a cut named the New Oder was made in 1753, and a dredg ing machine, wrought by a steam-engine, has latcly been proem ed in London, to deepen the bar at the mouth of the river.
The Warta is navigable for 200 miles into Poland ; the main navigation passes along the branch named the Nitza, as far as Nackel, where commences the Brom berg canal, constructed in 1772-5, by Frederick the Great, and the engineer Breckenhaff, It is 16 miles in length ; its fall from the Nctze to the Bralie at Brom berg is 67 feet, by nine locks. The navigation is then
continued by the River Brahe to the Vistula between Thorn and Culm.
The Vistula is navigable from Austrian Gallicia to the Baltic at Dantzic, nearly 400 miles. Its branch, the Bog, 100 miles, and as much by the Narau. By these the produce of Poland passes down to Dantzic sloops and flat-bottomed barges of from 30 to 60 tons.
Dantzic communicates with the sea at its harbour of Weichsehnunde, by a cut called the Fairwater. 'Fite Delta of the Vistula between Dantzic and Eibing, and as high as Marienwerder, is an embanked country, in tersected by many navigable cuts. The main body of the river falls, into the Frische-Haff, by which the inland navigation is prolonged to Konigsburg, on the Pregcl, which river is also navigable 30 miles further to Welaw, and SCENTS for the floating- of timber much higher.
The Pregel is supplied from a multitude of lakes in East Prussia. To improve the drainage of these, the canal of Angerburg was made in 1725. The Sapian canal was made at an early period ; also a series of cuts, to prolong their navigation to the Niemen below Tilsit, about 1690.
Various projects have been suggested to form a com munication between the Baltic and the Black Sca, by the branches of the Vistula and the Dnieper, but nothing has hitherto been effected, except the canal of Pinsk, begun in 1766. It commences in the Iasiolda, which falls into the Prypiez, and thence into the Dneister and Black Sea, and terminates above Slonim in the Stchara, which falls into the Niemen and the Baltic. A lake of three miles, which the canal traverses, supplies the lockage. It was made navigable in 1784, but not quite completed till 1802.
In the same quarter was formed the river Pina from the Dneister to the Muchawiez and the Bug, and thence to the Vistula. It was opened in 1784, but has hitherto been little used.
Hanover.—The Both the Ems and the Weser are navigable; the former to above Lingen, from which a canal proceeds 20 miles to the city of 'Munster. Thc Weser is naviga ble to Hoxter, near the Hartz mountains, about 100 miles from the sea, and 60 from the port of Bremen. 'fire only branch of note is the Aller, which admits boats to Zelle. The Leine is also navigable to Hano ver. There are various improvements by cutting off bends.