General Lubinski (_b_), with his division of cavalry, was to pass the right bank of the Bug (B), and leaving small detachments at Wyszkow (1) and Brok (2), he was to advance as far as the environs of Nar (3), not quitting the right bank of the river. All his care was to be devoted to the observing of the enemy, and to the preventing of any sudden passage of the river by him. In regard to his communications, the same instructions were given to him as to general Uminski. Having given these orders to the above mentioned corps, general Skrzynecki, with the main force (_d_), left suddenly the position at Kaluszyn (4), making a retrograde movement upon the great road, by Minsk (5), traversed Praga (6), and through Jablonna (7), and Zegrz (8), arrived on the 15th, at Serock (9). On the 16th, he passed the Narew (N), at this place, leaving a brigade of infantry and cavalry (_e_), under general Dembinski, upon the right bank, with orders to advance to Ostrolenka (10), through the towns of Pultusk, Magnuszewo and Rozany (11). This detachment was not to commence the attack on meeting the enemy, but was only to harass him and keep him in check, and detain him as near as possible to Serock. If the enemy should commence the retreat, this corps was to pursue him with the greatest activity, in order that at Ostrolenka, where the general in chief had determined to attack him, he might be exposed between two fires. On the 17th, this corps met the first advanced post (_f_) of the Russian imperial guard at Modzele, which, after a slight engagement, evacuated its position, and retired. Being pursued by the brigade of cavalry under general Dembinski, they, on the 18th, commenced the passage of the Narew, at Ostrolenka. In attempting this passage, the rear-guard of the enemy was overthrown, and four regiments of the light infantry of Finland were taken prisoners. This pursuit by the brave Dembinski was executed with such rapidity, that the corps of general Saken, which made a part of the grand corps of the guard, but was a little detached, was completely cut off from the main body and forced to take refuge in the palatinate of Augustow. It is much to be regretted that our main force (_d_) could not reach Ostrolenka; having to pass narrow roads, through forests, in which the artillery met with much obstruction. Otherwise, the whole of that imperial guard would have been surrounded.