themselves, which meant, of course, that they would have to be taken first before the advance could be continued. Furthermore, the fortresses also acted as a barrier, protecting the approaches to Kieff, enabling the undisturbed concentration of an army in that protected zone while the enemy would be busily occupied in battering his way through the fortress triangle. The latter were still more strengthened by the Rivers Ikwa and Styr, which flow to the southwest and north of them. The fortifications of all these three points were not of particularly recent origin, although they had been remodeled at various times since their original creation. Lutsk, a city of some twenty thousand inhabitants, is located on a small island of the Styr, and controls the Kovel-Rovno section of the Brest-Litovsk-Berticheff railroad. Some ten forts of various degrees of strength surrounded the central fortifications, forming a girdle of forts with a circumference of approximately ten miles. Dubno, southeast of Lutsk, a town of about fifteen thousand inhabitants, is located in the valley of Ikwa on its left bank, and protects the Brody-Zdolbitsa section of the Lemberg-Rovno-Vilna railroad, with its branches to Kovel, Brest-Litovsk, and to Kieff. The forts are not as numerous as at Lutsk, but are more advantageously located and, therefore, proved more difficult for the attacking Austro-Hungarian-German troops. Besides the Styr and Ikwa Rivers this comparatively small sector offers other natural advantages in the form of a number of smaller streams, the defense of which is greatly assisted by the marshy condition of their banks and the heavy growth of underbrush to be found there. Rovno, the largest of the three cities, with about twenty thousand inhabitants, was first fortified in 1887, and as a railroad junction is even more important than either Lutsk or Dubno. Its fortifications are built to serve as a fortified bridgehead. They amount to seven forts of which five are located on the left bank of the Ustje and two on the right. These forts were built in the form of a semicircle, at a distance of four to six miles from the city itself and with a circumference of approximately twenty-five miles. Originally this group of fortresses undoubtedly was intended to act as a basis for a Russian invasion of Galicia and Hungary rather than as a means of defense against an invasion from these countries. And, indeed, in the earlier part of the war, when the Russians forced their way into Galicia and to the Carpathian Mountains, they fulfilled their purpose with greater success than they were destined to achieve now as a means of defense. CHAPTER XXV FIGHTING ON THE DVINA AND IN THE DVINA-VILNA SECTOR