The Ist Corps of the Ist Army was necessarily left at Courcelles, south of Metz, to protect the railway, the other two were brought up leftward towards the Seille; and they were also by-and-by to cross the Moselle higher up, so as to avoid interference from the fortress. The French had started again on the retreat interrupted on the previous day, but proceeded little more than four miles[8] beyond Metz on August 15th. Their cavalry only went somewhat farther ahead, by both the roads to Verdun. The IIIrd Corps of the German IInd Army crossed the Moselle at Noveant, by the bridge which was found intact, and by a flying pontoon bridge; its artillery, however, was forced to make a detour by Pont a Mousson. It was not until late at night that the troops were all across and in bivouac close to the left bank. One Division of the Xth Corps remained at Pont a Mousson and the other advanced to Thiaucourt. The cavalry scouted farther forward towards the Metz-Verdun road, and struck in on the French cavalry near Mars la Tour. Several small engagements took place, but when early in the afternoon twenty-four Prussian squadrons had assembled, the French retired on Vionville. The Guard Corps and the IVth Corps crossed at Dieulouard and Marbache, higher up the river. The IIIrd Army advanced to the line Nancy-Bayon. On this day an attempt to seize the fortress of Thionville by surprise proved a failure. FOOTNOTES: [7] Clearly should be "right." [8] On the night of 15th, four of Bazaine's five Corps (less one Division) bivouacked at distances of from eight to ten miles westward of Metz; viz., from beyond Rezonville rearward to Gravelotte. BATTLE OF VIONVILLE--MARS LA TOUR. (August 16th.) In the Head-quarter of the IInd Army there was the belief that serious fighting with the French was no more to be anticipated on the Moselle, and therefore two Corps, the IIIrd and the Xth, were ordered to march on August 16th, northwards toward the road to Verdun by way of Gorze and Thiaucourt, while the other Corps were directed to advance by forced marches westwards towards the Meuse. The French retreat from Metz was, however, not completely effected on this day. The trains blocked every road, and in the forenoon three Divisions still remained behind in the Moselle valley. The Emperor, however, escorted by two brigades of cavalry, had departed at an early hour by the road through Etain, which was still comparatively safe. As the right wing of the army could not yet follow, the prosecution of the retreat was postponed until the afternoon, and the left wing, which had already begun the march, was sent back again into its bivouacs. But so early as nine o'clock Prussian shells startled the troops from their rest.