Subordinate to this contemplated attack by the crown prince, yet forming a part of it, and, in a measure, a fourth element in the campaign, was the double effort from the garrisons of Metz and Saarbruecken, combining with the armies of the Bavarian Crown Prince and the forces of General von Heeringen. The Second French Army, therefore, could not come to the aid of the Third, except in desperate need, for it was in the very forefront of the attack on Nancy. If the German left could pierce the French lines at Nancy and pour through the Gap of Lorraine, it would be able to take General Sarrail's army in the rear at Bar-le-Duc, and would thus completely hem it in, at the same time isolating Verdun, which, thus invested in the course of time must fall, forming an invaluable advanced fortress to the German advance. [Illustration: Battle of the Marne--Situation on September 9, 1914.] Before proceeding to the actual working out of this plan of campaign it may be well to recapitulate it, in order that each development may be clear. The German plan was to pierce the French line at three places, at Meaux, at Bar-le-Duc and at Nancy. General von Kluck, at Meaux, would cut off the Fifth and the Ninth Armies from communication with their base at Paris, the Bavarian Crown Prince would weaken General Sarrail's defense in the rear, and if possible come up behind him, and thus the stage would be set for the great onrush of the Imperial Crown Prince, who, with an almost fresh army, and with a most complete and elaborate system of communications and supplies, should be able to crush the weak point in France's defense, the army under General Sarrail. Such a victory was designed to shed an especial luster upon the crown prince and thus upon the Hohenzollern dynasty, a prestige much needed, for the delays in the advance of the crown prince's army had already given rise to mutterings of discontent. From a strategical point of view the plan was sound and brilliant, the disposition of the forces was excellently contrived, and the very utmost of military skill had been used in bringing matters to a focus.