Two of the three great fortresses forming the Polish triangle had now gone; Brest alone remained, and its doom was already sealed. While the Russians were preparing for a further retirement, their right, which rested on the Baltic Sea, was threatened with a new danger. On Sunday, 10th August, a German fleet tried to force a way into the Gulf of Riga; it was beaten off, but the attempt was renewed on the 15th and on the 16th. During a thick fog the Germans got into the Gulf on the 16th, and two days later tried to land troops at an unfortified port on the road to Petrograd. Four very large flat-bottomed barges, filled with troops, attempted to get ashore on the 20th; but the Russian light craft swooped down upon them, and captured or destroyed the whole of the landing force. Meanwhile a naval battle was going on throughout the length of the Gulf. The Russians lost an old gunboat, while the Germans had eight destroyers and two cruisers either sunk or put out of action, and a submarine driven ashore. On the 21st the Germans left the Gulf. Their attempt to outflank the Russian right had failed.
During the previous twenty days the Germans in the centre had pushed forward no less than one hundred miles; but the Russian armies had eluded them, and no crushing battle had taken place. The Germans had not yet given up all hope of overwhelming the Russians, but for the time being they were anxious to secure a strong line on which they might maintain themselves during the coming winter. They had also a new campaign in view. Already they were thinking of forcing a way through the Balkans to Constantinople, so as to open a road to the east and fling such forces into Gallipoli as would drive the British and French into the sea.
Now we must return to the doomed fortress of Brest. On the day that the German warships left the Gulf of Riga, Prince Leopold was close to the western walls of the fortress, while von Mackensen, east of the Bug, was threatening to take the forts from the rear. On 25th August Brest Litovski fell. It had held out long enough to enable the Russians to get away with the guns and supplies, and only a little wheat was left behind. Soon after the Germans entered the place a mine exploded and destroyed a thousand of their troops.
Map illustrating the various Stages of the Russian Retreat.
A, after the fall of Lemberg; B, after the fall of Warsaw; C, after the fall of Grodno; D, after the fall of Vilna.
You will see from the map on page [311] that the Russians, who had been holding the front around Brest, could use two railways to help them in their retreat. Most of them, however, had to retire on foot through the Marshes of the Pripet. Prince Leopold, in following them up, had to fight his way through the great forest region which lies to the north of Brest. It is said that in the recesses of this forest the European bison, elsewhere extinct, is still found. In the woods on the edges of the marshes the Russian rearguards fought fierce delaying actions, while their comrades trudged, unhasting but unresting, eastwards. Happily, the summer had been fairly dry, and it was possible for large numbers of men and guns to cross the swamps. By the end of August the Germans were thirty miles east of Brest, and were well within the marshy region.
Meanwhile, the chief interest of the struggle lay in the north. On 28th August von Buelow began his great attack on the line of the Dvina. In all the valley of that river, from Dvinsk to Riga, there is no crossing save at the little town of Friedrichstadt, some fifty miles from the coast. Below the town great stretches of marshy forest line the left bank of the stream, and no road follows its course on that side. On the other side the ground is harder, and along the line of the river runs the main Riga-Vilna Railway. The Russians held the left bank of the river, and von Buelow urged his men to the assault in the following words: "After the brilliant campaign on the Russian front, and the occupation of many cities and fortresses, you must make one more effort to force the Dvina and seize Riga. There you will rest during the autumn and winter, in order to march on Petrograd in the spring." On the morning of 2nd September the Russians were forced back for ten miles from the left bank of the river; but the bridgehead at Friedrichstadt still held out.
With the close of August the worst was over, and the turn of the tide had come. The tornado had blown itself out, the skies were clearing, and those who had been hurled back by the mighty blast were able to keep their feet and hold their own once more. The Russian line was nearly straight; the wings were hard pressed, but they could still resist; and the centre was too far within the Pripet marshes for easy capture. The struggle for dear life was over. Thenceforward the Russians were masters of their fate. They could retreat when and where they chose into the limitless expanses of their land. If they halted to fight a battle, it was because they saw some advantage to be gained, not because they were compelled to do so.