A few days after this decision had been formed, intelligence arrived at head-quarters that Napoleon himself was upon the Rhine. Before the ultimatum reached the hands of General Knobelsdorff in Paris, Napoleon had quitted the capital, and the astonished Ambassador could only send the ultimatum in pursuit of him after he had gone to place himself at the head of 200,000 men. The news that Napoleon was actually in Mainz confounded the diplomatists in the Prussian camp, and produced an order for an immediate advance. This was the wisest as well as the boldest determination that had yet been formed; and an instant assault upon the French divisions on the Main might perhaps even now have given the Prussian army the superiority in the first encounter. But some fatal excuse was always at hand to justify Brunswick in receding from his resolutions. A positive assurance was brought into camp by Lucchesini that Napoleon had laid his plans for remaining on the defensive on the south of the Thuringian Forest. If this were true, there might yet be time to improve the plan of the campaign; and on the 4th of October, when every hour was of priceless value, the forward march was arrested, and a new series of deliberations began at the head-quarters at Erfurt. In the council held on the 4th of October, a total change in the plan of operations was urged by Hohenlohe's staff. They contended, and rightly, that it was the design of Napoleon to pass the Prussian army on the east by the valley of the Saale, and to cut it off from the roads to the Elbe. The delay in Brunswick's movements had in fact brought the French within striking distance of the Prussian communications. Hohenlohe urged the King to draw back the army from Erfurt to the Saale, or even to the east of it, in order to cover the roads to Leipzig and the Elbe. His theory of Napoleon's movements, which was the correct one, was adopted by the council, and the advance into the Thuringian Forest was abandoned; but instead of immediately marching eastwards with the whole army, the generals wasted two more days in hesitations and half-measures. At length it was agreed that Hohenlohe should take post at Jena, and that the mass of the army should fall back to Weimar, with the object of striking a blow at some undetermined point on the line of Napoleon's advance. [Encounter at Saalfeld, Oct. 10.] [Napoleon defeats Hohenlohe at Jena, Oct. 14.] [Davoust defeats Brunswick at Auerstädt, Oct. 14.] [Ruin of the Prussian Army.]