And the camp must be so placed as to stretch its protecting influence over one, or more, important roads.

It need not be on any one of them: in fact, it was better that it should be some distance away; for it thus fulfilled better the all-important function of a "flanking position." Such a position Phull had discovered at Drissa in a curve of the River Dwina.

It was sufficiently far from the roads leading from the Niemen to St.Petersburg and to Moscow efficiently to protect them both.
There, accordingly, he suggested that vast earthworks should be prepared; for there, at that artificial Torres Vedras, Russia's chief force might await the Grand Army, while the other force harassed its flank or rear.[259] Napoleon had not probed this absurdity to its inmost depths: but he early found out that the Russians were in two widely separated armies; and this sufficed to decide his movements and the early part of the campaign.

Having learnt that one army was near Vilna, and the other in front of the marshes of the Pripet, he sought to hold them apart by a rapid irruption into the intervening space, and thereafter to destroy them piecemeal.

Never was a visionary theory threatened by a more terrible realism.