n fortresses, fell.
(Vol. III, 276-312.)

Having thus disposed of the Galician armies, Mackensen turned
northeast from the San, struck at Lublin and Cholm (Vol. III,
357-365), and through them at Brest-Litovsk, far in the rear of the
Russian armies in Poland. At the same time Hindenburg in East Prussia
moved south, aiming at Grodno and Vilna, also behind the Warsaw front
(Vol. III, 256-361), while a third Germany army invaded the Courland
and aimed at Riga. (Vol. III, 337.)

The Russian armies in Poland were thus threatened with complete
envelopment; they were caught between the closing jaws of the pincers,
which were Mackensen and Hindenburg. For a certain time it was not
clear whether the gigantic double thrust might not result in the
capture of the whole Russian army in Poland. But this did not happen.
Warsaw was evacuated (Vol. III, 356), Ivangorod, Novo Georgievsk, the
fortresses along the Bobr-Narew-Niemen barrier fell (Vol. IV,
176-181), but the Russian armies drew back upon Riga, Vilna, and
Brest-Litovsk. (Vol. IV, 186-188.)

[Illustration: October 1, 1915, at the End of the Russian Retreat.
Dotted line shows Russian front on April 1, 1915.]

RUSSIA SURVIVES

At Brest-Litovsk there was only a brief halt and then the Russians
resumed their retreat upon Pinsk and the Pripet Marshes. Behind the
Dvina from Riga to Dvinsk the northern army stood fast. But the
central armies, retiring upon Vilna, were nearly trapped and once were
actually cut off by German cavalry. (Vol. IV, 193-223.)

By September the great campaign approached its end. The Russians at
last took root on a line from Riga, through the Pripet Marshes to
Rovno and thence to the Rumanian boundary. (Vol. IV, 184-255.) The
czar sent the grand duke to the Caucasus and took command himself
(Vol. IV, 188), an allied offensive in the west in Champagne and
Artois (Vol. IV, 52-81) made sudden demands upon German man power, as
the Russian advance in East Prussia and Galicia had taxed German man
power in the days of the Marne, and so, by October, it was plain that
the second great German effort had also failed. Russia had not been
destroyed, she had not been put out of the war for any long period;
Russian armies were to resume the offensive the following June.

As in the west, Germany had conquered wide territories, she had taken
fortresses, provinces, vast numbers of prisoners and guns, but a
decision had escaped her. She was still confronted by the cert