234 



GEEMANY. 



way through suhterranean channels into the Rhine. The spring which gives hirth 

 to the Aach, a tributary of the Rhine, is almost wholly fed from the Danube. In 

 1876 fresh fissures opened in the bed of the river, and they would have swallowed 

 up the whole of its water had not the neighbouring manufacturers, fearful of 

 losing their water-power, stopped them up. 



At Immendingen, close to the Wiirttemberg frontier, the Danube turns away 

 to the north-east. It now flows through a gorge of the Swabian Jura, hemmed in 

 by cliffs 300 feet in height, but occasionally widening into secluded valleys, with 

 groves of birches and beeches. The rivulets which join the Danube in this part 

 of its course are distinguished, like all others flowing for long distances through 



Fig. 135.— The Donau-Ried. 

 Scale 1 : 215,000. 



10°|25' E ofG 



4 MUes. 



subterranean channels, for their blue transparent water. One of these tributaries, 

 the Blau, rises from a cavern opening at the foot of a hill near Blaubeuren, known 

 as the " Blue Pot," on account of the colour of the water which fills it. At TJlm 

 the Danube enters Bavaria, and thanks to the volume of water discharged into it 

 by the Alpine-born Illcr, it at once becomes the great river highway of Southern 

 Germany. The Hier itself is navigable, and the Danube below its confluence has 

 a width of 210 feet, and an average depth of 3 feet. Large square barges, 

 known as " Schachteln," or bandboxes, at Vienna, and capable of carrying a 

 hundred tons of merchandise, almost daily take their departure from Neu-Ulm, 

 opposite the mouth of the Hier. Each of the tributary streams adds its 



