[Illustration: The Polish Theatre of War.]
When you examine the map you will be sure to notice that in all this western part of Russia there are but few railways for so large an area of country. There are also few good roads, for the country is so swampy that they are difficult to make and to keep passable. Without good roads and railways a modern army cannot keep the field; it cannot march, and it cannot supply itself with the necessary provision for men and guns. The general who has good roads and railways at his command can bring his men quickly and without great fatigue to the desired positions; he can move them rapidly to the points where he means to make his attacks, and he can supply himself promptly and continuously with food and ammunition. He can also bring up reinforcements rapidly, and carry his wounded and prisoners to the rear. Without good roads and railways he is greatly hampered. You can easily see that the Russian commander-in-chief has great difficulties to overcome because of the lack of good roads and railways in Poland.
When, however, we turn to the German side of the frontier, quite a different picture presents itself. The Germans have always paid great attention to military railways, and have planned and constructed them throughout the empire with great diligence and foresight. It was by means of their splendid system of railways that they were able to mobilize their troops so quickly, and fling them without an hour's delay into Belgium. Behind the eastern frontier of Poland they have two double lines of railway, and these are united into a perfect gridiron by criss-cross lines. By means of this railway system they can carry their troops rapidly to any part of the frontier, and can readily supply themselves with food and ammunition. As we shall see later, the German generals have been able to transfer their men from the north to the south by railway, and have thus been enabled to carry out rapid movements which are quite impossible to the Russians.
Before I close this rather dull but very necessary chapter, I must tell you something about the two provinces which form the northern and part of the southern boundaries of Russian Poland. Let us look first at the country which lies between the Lower Vistula and the Lower Niemen, the region in which the Germans and Russians first came to blows. Along the coast, which is lined with sand dunes, you see two lagoons almost entirely cut off from the Baltic Sea by tongues of land. Into the westward of these the Vistula and the Pregel discharge themselves; by means of the other lagoon the river Memel finds its way to the sea.