Napoleon, having done whatever lay in his power to remedy the disorders of his commissariat--and this, after all, does not appear to have been much--at length reappeared in the field. He had now determined to make St. Petersburg his mark: he counted much on the effects which a triumphal entry into the capital would produce throughout the country; and the fleet at Cronstadt was in itself a prize of the utmost importance. He directed, therefore, all his efforts towards the Dwina, where the Russian commander-in-chief had now halted on extensive intrenchments, and Riga. This town, however, was now defended, not only by Essen, but by the English sailors of Admiral Martin's fleet, and resisted effectually; and, to the confusion of Napoleon, he was repelled in three successive attempts to force Barclay's camp at Dunaburg. He upon this changed his plan of operations, and resolving to march, not for Petersburg, but for Moscow, threw forward the centre of his army, under Davoust, with the view of turning Barclay's position, and cutting off his communications with Bagrathion. That general was compelled by this movement to pass the Dnieper (or Borysthenes); and Barclay, on perceiving the object of Davoust's march, broke up from the camp on the Dwina, and retired upon Vitepsk, where he hoped to be joined by Bagrathion. Davoust, however, brought Bagrathion to action near Mohilow, on the 23rd of July; and as the French remained in possession of that town at the end of the day, the Russians found themselves under the necessity of altering the line of their retreat. Bagrathion informed Barclay that he was now marching, not on Vitepsk, but on Smolensko, and the commander-in-chief felt the necessity of abandoning Vitepsk also. During three days (the 25th, 26th, and 27th of July), his troops were engaged with the French at Vitepsk; and, though Napoleon's bulletins announced three splendid victories, the result was that the Russians left their position in admirable order, and retired altogether unmolested on the proposed point of junction. Meantime Regnier, on the right wing, and Oudinot, on the left, were defeated; the former by Tormazoff, the latter by Witgenstein, both with severe loss. The Emperor halted at Vitepsk for several days; "his troops," as the bulletins admitted, "requiring refreshment." The Russian plan of defence was already ascertained--and alarming. The country was laid utterly desolate wherever they retired; every village was burned ere they quitted it: the enthusiastic peasantry withdrew with the army and swelled its ranks.