But while on the right the victory appeared completely gained, on the left every thing seemed to be lost:  the eagerness of the Swiss and the Croats was the cause of this reverse.  Their rivalry had up to that period wanted an opportunity of showing itself.  From a too great anxiety to show themselves worthy of belonging to the grand army, they acted rashly.  Having been placed carelessly in front of their position, in order to draw on Yacthwil, they had, instead of abandoning the ground which had been prepared for his destruction, rushed forward to meet his masses, and were overwhelmed by numbers.  The French artillery, being prevented from firing on this medley, became useless, and our allies were driven back into Polotsk.

It was then that the batteries on the left bank of the Duena discovered, and were able to commence firing on the enemy, but instead of arresting, they only quickened his march.  The Russians under Yacthwil, in order to avoid that fire, threw themselves with great rapidity into the ravine of the Polota, by which they were about to penetrate into the town, when at last three cannon, which were hastily directed against the head of their column, and a last effort of the Swiss, succeeded in driving them back.  At five o’clock the battle terminated; the Russians retreated on all sides into their woods, and fourteen thousand men had beat fifty thousand.

The night which followed was perfectly tranquil, even to Saint Cyr.  His cavalry were deceived, and brought him wrong intelligence; they assured him that no enemy had passed the Duena either above or below his position:  this was incorrect, as Steingell and thirteen thousand Russians had crossed the river at Drissa, and gone up the left bank, with the object of taking the marshal in the rear, and shutting him up in Polotsk, between them, the Duena, and Wittgenstein.

The morning of the 19th exhibited the latter under arms, and making every disposition for an attack, the signal for which he appeared to be afraid of giving.  Saint Cyr, however, was not to be deceived by these appearances; he was satisfied that it was not his feeble entrenchments which kept back an enterprising and numerous enemy, but that he was doubtless waiting the effect of some manoeuvre, the signal of an important co-operation, which could only be effected in his rear.

In fact, about ten o’clock in the morning, an aide-de-camp came in full gallop from the other side of the river, with the intelligence, that another hostile army, that of Steingell, was marching rapidly along the Lithuanian side of the river, and that it had defeated the French cavalry.  He required immediate assistance, without which this fresh army would speedily get in the rear of the camp and surround it.  The news of this engagement soon reached the army of Wittgenstein, where it excited the greatest joy, while it carried dismay into the French camp.  Their position became dreadfully critical.  Let any one figure to himself these brave fellows, hemmed in, against a wooden town, by a force treble their number, with a great river behind them, and no other means of retreat but a bridge, the passage from which was threatened by another army.