ver flows through West Prussia, from Thorn to the Gulf of
Danzig. For almost a hundred miles, from Thorn to Novo Georgievsk, it
cannot actually be considered of defensive value to Russia; flowing
slightly northwest from the latter fortress to the border it is open to
German use on either side. But at that point, about twenty miles
northwest of Warsaw, any army coming along its valley would have to take
first this important fortress before it could continue farther into
central Poland. Should it fail in this it would have to withdraw its
forces from the right bank and then force a crossing at some point
between Novo Georgievsk and the point where the Vistula enters Russian
Poland from Austrian Poland, a few miles east of Cracow. It is at this
point also that the Vistula is swelled by its most important
contributary, the Bug River, which, roughly speaking, flows parallel to
the Vistula at a distance of about seventy miles from the Galician
border to a point on the Vilna-Warsaw railroad, about fifty miles east
of Warsaw, where it bends toward the west to join the Vistula. The Bug
River thus forms a strong secondary natural line of defense. In the
north the Narew--a tributary of the Bug--forms an equally strong barrier
against an army advancing from East Prussia.

There cannot be much doubt that the plan of the Central Powers
originally was to take Poland without having to overcome these very
formidable obstacles. If Von Hindenburg had succeeded after the battle
of Tannenberg in crossing the Niemen, and if, at about the same time the
Austro-Hungarians had also succeeded in defeating their Russian
adversaries in Galicia, described in another chapter, this object could
have been accomplished very easily by a concerted advance of both along
the east bank of the Bug, with Brest-Litovsk as the most likely point of
junction. The result would have been twofold: in the first place all of
Poland would have been in the hands of the Central Powers; for Russia
either would have had to withdraw its forces from there before their
three main lines of retreat--the railroads from Warsaw to Petrograd,
Moscow, Kiev--had been cut by the invaders, or else the latter would
have been in a position to destroy them leisurely, having surrounded
them completely. In the second place it would have meant the shortening
of the eastern front by hundreds of miles, making it practically a
straight line from the Baltic Sea to some point on the Russo-Galician