From Ypres seawards runs a canal which meets the Yser six miles south of the large village of Dixmude.[57] From Dixmude on to the sea, a distance of eleven miles, we find the canalized Yser, the main waterway of the district. Near the left bank of the canal, at a distance of about a mile and a half, runs a single-line railway,[58] which passes the villages of Pervyse[59] and Ramscappelle,[60] and has its terminus at the mouth of the river. No railway crosses the Yser between Dixmude and Nieuport, but the road from Bruges forks and sends one branch across the stream to Nieuport, and the other to Pervyse. A number of small creeks of brackish water flow through the low, marshy meadows, below the level of the sea, and bring their sluggish tribute to the Yser. Along the edges of the canal are two or three "islands" of higher ground; but nowhere, until we reach the dunes of the seashore, are there any elevations or commanding positions for guns. It is a blind, sodden country, as ill-fitted for the passage of troops and heavy guns as the coast region of Essex. To the inhabitants of this amphibious district water is a foe in peace and a friend in war. In times of great peril the sluices of the myriad canals can be opened, and the whole flat district from the railway embankment to the Yser and beyond can be flooded, and thus rendered impassable for an army. You can easily understand that the Belgians would not flood the country until every other means of defence had failed; for the land so submerged would be ruined for agriculture, and years of labour would be necessary to restore it to its former condition. The sluices were opened in the days of Marlborough, and again in 1793-94. You are soon to hear how the progress of the Germans was similarly stayed in 1914. The idea of calling in the aid of water as a defence has long been familiar to Belgian soldiers, and a scheme for flooding the country had been prepared before the war broke out. I have already described how the Allies held the avenues to the Channel ports at Arras and La Bassée. Two other efforts were made by the Germans to break through the line of defence--the one at Ypres, the other between Dixmude and the sea. All these four attacks were going on at the same time, and all were closely connected; but for the sake of clearness they must be described separately. We will now see how the Belgians and the French barred the road to Calais by way of the Yser, and in a later chapter I will describe the great struggle which took place round Ypres.