The forces in front of Vilna had only one good railway line by which they could retire eastward, and only one good road—a causeway running across the marshes towards Minsk. On 15th September it was discovered that some 40,000 German cavalry, with 140 guns, were sweeping round so as to cut the railway and capture the causeway. Here was a terrible danger. If the cavalry could hold the railway and the causeway, the Russians in the Vilna salient would be surrounded, and nothing could save them. Not an hour must be lost. Vilna was abandoned on 18th September, and the troops were hurried eastwards by means of the road and railway. Rearguards on the right fought desperate holding battles, but on the 20th the gap through which the Russians were retreating had shrunk to little more than fifty miles. The Minsk railway was in danger; only the causeway, densely packed with guns, wagons, convoys, ambulances, and troops, was clear.
Suddenly, in this moment of peril, the German thrust weakened. While the cavalry were sweeping round to the rear, the artillery and infantry to the west of the fortress made no push. Owing to the bad and crowded roads they could only proceed very slowly, and thus the Russians were afforded what they most needed—time. No longer were they without arms and ammunition. The Russian factories had worked miracles, and now the Tsar's armies were able to meet the enemy on equal terms. On the evening of 20th September, when the retreating Russians were thirty miles east of Vilna, their right wing fell upon the German cavalry and drove them back with the bayonet. For some days there was heavy fighting, but by the end of the month the Russian line was straight again. Once more the Germans had been foiled.
Meanwhile the army of Brest, which had never been in serious danger, had been pursued, but the pursuers were now firmly held. On the Dvina von Buelow had made but little progress, while in the south Ivanov had held his ground, and had even won victories against the German right. He had overthrown a force moving against Tarnopol and another which was advancing further south, and had won one of the most successful of the smaller battles. Of course the Germans had made counter-attacks upon him, but they had been unsuccessful, and Ivanov had advanced in some places as much as twenty miles. His captures at the end of the month amounted to 80,000 men and many guns.
Thus the end of September saw the Germans held in check. They had won Vilna and Grodno, but they had failed to cut off the troops in these salients, and had not made good the line of the Dvina. Winter was almost upon them, yet they had not found a suitable position for winter quarters. Meanwhile the Russians were growing in strength every day.
During the terrible months from May till September the nation had suffered greatly, and misfortune had been heaped on misfortune. The spectacle of troops falling back day by day, the endless stream of wounded arriving at the bases, the highroads thronged with homeless peasants, and the seeming hopeless struggle would have broken down the spirit of most nations and brought about revolution; but in Russia, though there was some unrest, there was no revolution. Even the peasants who had lost their all, and had not where to lay their heads, bore their sufferings without complaint. A correspondent who talked with some of them tells us they felt that they were playing their part in defeating the hated enemy, as their fathers had done before them. They hoped for an early winter in order that their enemy might perish of cold and starvation, and they thought nothing of the sufferings that the winter would bring to them and their children. "I have heard them say again and again: 'We must win now, regardless of the cost and the time it takes. The sacrifices we have suffered are too great for us to hesitate at anything short of victory.'"
When the German cavalry were flung back from the rear of Vilna, the retreating Russians once more breathed freely. The end of the summer campaign had come, and still the Germans had delivered no smashing blow. During the month of October von Hindenburg strove fiercely to carry the line of the Dvina, in order to secure Dvinsk and Riga as winter quarters. The Russian right lay on the sea, and behind the river stretched a wilderness of marsh and lake almost impassable for troops and big guns. Riga and the line of the river south of it were defended by great stretches of bogland, and the patches of dry ground were cut up by many sluggish streams flowing in reedy channels. General Ruzsky, who was holding Dvinsk, had learned the lesson of Verdun and pushed out his defences far from the city. In the course of a big attack on 26th September the Germans came within eight miles of the fortress, but they could approach no nearer. An attempt to reach Riga by the coast road was foiled by the guns of the Russian fleet.
On 3rd October von Hindenburg began a new series of thrusts against the line of the river, but made very little progress, and when the Russian counter-attacks began the German losses were very great. Before long 50,000 of the enemy had fallen, and their goal was as far off as ever. Von Hindenburg now saw that he could not succeed against Dvinsk, and began a determined effort to capture Riga. He managed to win a marshy island in one of the arms of the river; but here he was stayed, and soon his troops were blown off the island. He was now fighting an army that was as strong as his own and could return shell for shell and shot for shot. By the end of October all his efforts against Dvinsk and Riga had come to nothing, and he was forced to dig in for the winter in a most inhospitable land. The snows were beginning to fall, bitter north winds were sweeping over the land, and no great movement was possible until the spring.