The Germans have by this time learned the reason why they suffered such an important check at Dvinsk, and therefore I shall not be giving away any military secrets by describing the Dvinsk sector of the Dvina line, which the Russians took up after their retreat from Poland. It was an excellent one from the strategical point of view, and one which they have held ever since. There are three railway lines available, of great importance for the army--one from Riga to Oriol, which follows the line of the Dvina as nearly as possible; the main line from Petrograd to Warsaw; and a branch line of the Lembo-Rommy railway, with a junction connecting the three together. When the Russian army was about to make a stand at Dvinsk, at the beginning of the war, the civil population of the town received orders to leave, and men, women, and children were sent to seek refuge at a sufficient distance for their safety, out of reach of Prussian guns. The terror-stricken people had no time to take their household goods or the treasures they so much prized; they simply had to flee, they knew not whither. Vanda Zarden, however, was not among that stricken crowd. With bowed head and prostrate form, she was kneeling before an _ikon_ in the home that had been hers for so many years, the home she had been brought up in and where her children were born. Her husband had long been dead, and her sons were all married except Mooska the Cossack, the pride of her life and the comfort of her old age. The Cossacks of the Don, the distant Carpathian mountains, and other remote regions are among the most famous cavalry in the world, and it is the ambition of many a Russian mother that her boy will obtain a commission in a Cossack regiment or even a place in its ranks. Thus it was that Mooska Zarden was only a few hours old when his father registered his name in Dvinsk as a trooper. He was determined that one of his sons should have the distinction of serving the Czar as a mounted soldier; so Mooska was trained for this branch of the service, and learned all about horses. When he joined the regiment it was soon discovered how quickly he could tame the wildest steeds and teach them many things beside their drill. His own horse followed him about like a dog, and would lie down at the word of command. Mooska also taught him to lift a man in his teeth by the belt of his uniform and carry him, which was not a part of the regulation army drill. And now the hour had come when Mooska must leave Dvinsk, his native town, and the aged mother who refused to flee. His heart was heavy within him at the thought of deserting her in the time of peril; but his regiment was ordered to join the army that was marching towards the Masurian Lake district to oppose the advance of the Huns. This was during the earlier days of the war, when there was not much known about these wilds nor about the lake district that proved so full of surprises for the great Russian armies that were rolling westwards.