The surest way of getting Marlborough out of the Upper Danube is to threaten his line of supply. He will then be compelled to fall back northward upon his base. Further (though Tallard did not know it at the moment), there is present the very real difficulty of friction between the two commanders of the army opposing him. Marlborough and Baden are not getting on well together. If it were possible for Marlborough to persuade Baden to go off on some little expedition of his own, withdrawing but a few soldiers, Marlborough would be well content, and Marlborough is by far the more formidable of the two men. But though the opportunity for such a riddance of divided command is open, for Prince Louis of Baden is anxious to besiege Ingolstadt, Marlborough dares not weaken the combined forces, even by a few battalions, now that Tallard has effected his junction with the Elector and with Marcin, and that a formidable force is opposed to him. These elements in the situation, once clearly seized, the sequel follows from them logically enough. The above describes the situation on the 5th of August. On the 6th, Wednesday, the united Franco-Bavarian force began its march northward towards the Danube, a march parallel with Marlborough's line of supply, and threatening that line all the way, ready to cut it when once the northern bank of the Danube was reached. Marlborough was compelled, in view of that march, to go back northward, step for step with his opponents. The artery that fed him was in danger, and everything else must be neglected. In the evening of that Wednesday, August the 6th, Tallard and the Elector were at Biberach, Marlborough and Baden at Schobenhausen, which, as the map shows, lies also a day's march to the north from the last position these troops had held, and was on the way to the crossing of the Danube at Neuburg, as the Franco-Bavarians were on the way to the crossing of the same great river at Dillingen. On the 7th there was no movement, but on the 8th, the Friday, as the Franco-Bavarian host approached the crossing of the Danube at Dillingen, their leader (if Tallard may be regarded as their leader--he was nominally under the orders of the Elector, but he was the marshal of Louis XIV.) heard suddenly that Eugene _had appeared at Hochstadt with thirty-nine squadrons and twenty battalions_. The trick was done. The rapid and secret march of Eugene had been accomplished with complete success, and his force was within speaking distance of Marlborough's. When the news came to the French camp, it was even there evident what a sudden transformation had come over the campaign; but to one who could see, as the historian sees, the moral condition of both forces, the event is more significant still.