6. THE EASTERN FRONT. 1. The Strategic Situation on the Eastern Front, To understand the war on the Eastern Front, between Russia and her Teutonic enemies, one must grasp the significance of the map: the great Polish salient, the railways, and the gen erally flat character of the terrain. Russian Poland, with its political and railway centre at Warsaw on the Vistula, projects westward like a great wedge of Russian territory driven between the German provinces of East and West Prussia on the north and the Austrian province of Galicia on the south. The wedge is roughly 200 miles from north to south, and 250 miles from east to west. Its western point is only 180 miles via Posen (or Prussian Po land) from Berlin, and it touches the whole eastern frontier of one of Germany's richest and most valuable provinces— Silesia. This Silesian boundary is a purely artificial one, easy to cross in either direction. But the Russian strategy did not aim at crossing it, at any rate, at the outset of the war, partly on account of lacic of adequate railways and transportation, and partly because of the danger to which the Russian flanks would have becn exposed. Russia could not afford to run the risk of having a Russian army in the Polish salient ((pinched)) by a German-Austrian thrust southward from East Prussia and northward from Galicia. Obviously nb direct western ad vance against Silesia could be undertaken by Russia until she had safeguarded her flanks by tite conquest of East Prussia and Qalicis.
—until her armies were in possession of the Lower Vistula and of the passes of Carpathian Mountains. Russia's first strategic task, there fore, was to occupy East Prussia and Galicia on the two sides of the Polish salient.
The railways available for the movement of Russian troops were very inadequate as com pared with the splendid system of strategic rail ways which Germany and Austria had con structed. Germany had 17 lines of railway leading to the Russian frontier, which, it was estimated, would enable her to send 500 troop trains daily, so that she could concentrate some 600,000 men on that border within a few days of a declaration of war. On the Russian side there were only six railway lines. So, too. with Austria. The Carpathians had been pierced by seven railways so that troops could be poured from Hungary into Galicia and up to the Russian border at the rate of 250 trains every 24 hours. As against this Russia had only four lines. The German and Austrian railways
consisted not only of the great trunk lines for commercial use, but connected with these were also numerous strategic lines running parallel and close to the frontier with many small branches shooting out rail-heads to the tcywns on the frontier. From such rail-heads troops could be rapidly detrained and military supplies sent forward by automobile trucks, The Russians, however, had no such network of railways parallel to the frontiers; they had nothing but the few trunk lines which crossed the frontier at right angles. Thus Germany could shift her army corps very rapidly along the Russian frontier as needed. Russia could not shift hers nearly so quicicly, and only slowly could she bring up reinforcements from the vast interior stretching to Siberia and the Caucasus. This inferiority in railways will explain several of the severe reverses which Russia suffered after apparent initial successes. Germany's advantage in the matter of railways, however, became less and less as she invaded Russian territory and found herself handi capped by lack of railways and by bad roads; the further German armies penetrated Russia, the more they were slowed down until finally brought to a standstill.
The character of the terrain, together with the inadequacy of the railways, had long be fore the war determined the Ruisian general staff not to attempt to defend the western part of the Polish salient; for the country ts a vast, flat, monotonous, open plain (the name °Poland)) comes from the Slavic ((polyes mean ing steppe or plain). Over this plain German armies rapidly mobilized in Silesia could easily sweep. Moreover, a large Russian army in the .western part of the Polish salient was al ways in danger of having its line of communica tions throngh Warsaw cut off, or of being sur rounded by German and Austrian armies com ing south out of East Prussia, or north out of Galicia. Therefore Russia had selected the Vistula River as the first line of defense. Ris ing in western Galicia, near Cracow, at the corner where the German, Austrian and Russian empires met, the Vistula flows for 100 miles northeastward, and forms the boundary between Russian Poland and Galicia. In this region it receives the flood of water which tumbles north ward from the slopes of the Carpathian Moun tains in the Dunaiec, Wisloka and San rivers.