The Russian main army, which, since the last of March had been on the defensive, from weakness or from indecision, on the 23d of April began to change its position, and to take the offensive. Having received intelligence, as we may suppose, of the disasters of Sierawski, and also of the passage of general Dwernicki into Volhynia, general Diebitsch gave orders to the corps of Witt and Kreutz to pass the Wieprz at Kock, and to attack our detachment at Zelechow, which was forced to retire. On the same day, (23d) the brigade of colonel Dembinski was attacked at Jeruzalem, without any decisive result. Those small attacks by the enemy served, however, as an indication of the intention of general Diebitsch to take the offensive on a larger scale. To meet this intention, all our detachments received orders to hold themselves in readiness. Firstly, these detachments were to concentrate themselves upon a line of operations, between Kaluszyn, Siennica, and Zelechow. [_The reader can refer to Plan_ VI.] The whole line, in case of attack, on whatever quarter it might be, was to make a retrograde movement, upon the same plan as heretofore, as far as the field of Wawr. General Pac, in particular, who was the farthest removed from Zelechow, was to use the utmost vigilance, and to make this retrograde movement in the promptest manner, when occasion required. On the 25th of April, in fact, marshal Diebitsch commenced his attack at two principal points, Boimie and Kuflew. Upon the last of these two points, he threw his greatest force, intending to pierce our line there, and by a diversion at Minsk to divide our forces. Besides the prevention of this design, the defence of Kuflew was of the greatest importance to us from the circumstance that along the whole course of the river Swider, at Latowicz, Starygrod, &c, were posted various small detachments, which would have been cut off, if we should be forced to make a sudden evacuation of that point. COMBAT OF KUFLEW. [_See Plan_ XXIV.]