The army which had been quartered on the Vistula, broke up from thence about the 1st of June, and advanced in different columns, and by forced marches upon the Niemen, which it reached upon different points, but chiefly near Kowno, upon the 23d, and commenced the passage on the 24th of the same month. From the Vistula to the Niemen is about 250 wersts, equal to 235 or 240 English miles; from Kowno, on the banks of the Niemen, to Vitepsk, on the Dwina, is nearly the same distance. The whole space might be marched by an army, moving with its baggage, in the course of forty marches, at the rate of twelve miles a-day; yet the traversing this distance took, as we shall presently see, four days more, notwithstanding the acceleration of forced marches, than would have been occupied by an army moving at an ordinary and easy rate, and carrying its own supplies along with its columns. The cause why this overhaste should have been attended with actual delay, was partly owing to the great mass of troops which were to be supplied by the principle of the marauding system, partly to the condition of the country, which was doomed to afford them; and partly, it may be, to the political circumstances which detained Napoleon twenty precious days at Wilna. The first reason is too obvious to need illustration, as a flying army of 20,000 men bears comparatively light on the resources of a country, and may be pushed through it in haste; but those immense columns, whose demands were so unbounded, could neither move rapidly, nor have their wants hastily supplied. But, besides, in a country like Lithuania, the march could not be regular, and it was often necessary to suspend the advance; thus losing in some places the time which great exertion had gained in others. Wildernesses and pathless forests were necessarily to be traversed in the utmost haste, as they afforded nothing for the marauders, on whose success the army depended for support. To make amends for this, it was necessary to halt the troops for one day, or even more, in the richest districts, or in the neighbourhood of large towns, to give leisure and opportunity to recruit their supplies at the expense of the country. Thus the time gained by the forced marches was lost in inevitable delays; and the advance, though attended with such tragic consequences to the soldier, did not secure the advantage which the general proposed to attain. [Sidenote: WILNA.]