The construction and completion of the fortifications at Warsaw and Praga were not less actively pressed than the administration of the army; and, as the left bank of the Vistula, on which Warsaw is situated, commands the right, with Praga and its environs, general Skrzynecki placed on the left bank twelve pieces of cannon of 24 pound calibre, on the heights of Dynasow and Zoliborz. This battery covered with its fire the neighboring plain, to the extent of a circle of three miles in diameter, and could overpower any battery which the enemy might open against Praga. That town is divided into two parts, the first of which borders on the Vistula, and formed the bridge-head of the position; the other part, which is more distant, was not fortified. This latter part was taken possession of by the Russians, after the battle of Grochow, and was burnt by them. To the inhabitants this was a disaster; but for our defence it was a most favorable circumstance, as it left the enemy's approach unprotected, and opened a range for our fire. General Krukowiecki, who was appointed governor of Warsaw, continued the works in the city and its suburbs with great activity. The rampart, which surrounds the city beyond the walls, had been constructed for a defence against musquetry only; but at several points, it was now made defensible against artillery. The ditch was considerably widened and deepened. Beyond the ramparts, the city was surrounded by a chain of _lunettes_, placed in two lines, so as to alternate with each other, and afford a mutual support. The city itself was divided into six parts; each part being susceptible of an independent defence. The barricades in the streets were constructed with openings for the fire of the artillery, above which platforms were raised for the infantry. Mines were also prepared in different parts of the city.[44] The positions of the army, and of the different detached corps were as follows:--The infantry, the artillery, and the 4th division of cavalry of the grand army, were at Warsaw and its environs. Three divisions of cavalry were posted above and below the city, on the left bank of the Vistula, whose duty it was to patrol the river, and to guard the communications between the fortress of Modlin and Kozienice. This chain of patrols, by watching the movements of the enemy, kept the grand army continually advised of his intentions, and in constant readiness to act against him, at any point which he might choose for attempting the passage of the Vistula.