Saarbrücken was evacuated after a gallant defence and repeated counter-strokes, but the French did not press across the Saar; convinced, possibly, that they had wasted their strength in a stroke in the air, and had nowhere gained any insight into the dispositions of the enemy.
The French military chiefs now hesitated for a long while between conflicting resolutions. Orders were given and recalled on the strength of mere rumours. The left wing was reinforced because 40,000 Prussians were supposed to have marched through Trèves, the Guard received contradictory orders, and the bare apparition of a small German force about Lörrach in the Black Forest occasioned the order that the VIIth Corps must remain in Alsace. Thus the French forces were straggled over the wide area between the Nied and the Upper Rhine, while the Germans were advancing in compact masses towards the Saar.
This scattered state of their forces finally induced the French leaders to divide them into two separate Armies. Marshal MacMahon took command, but only provisionally, of the Ist, VIIth, and Vth Corps, of which the latter had therefore to draw in to him from Bitsch. The other Corps remained under Marshal Bazaine, with the exception of the Imperial Guard, the command of which the Emperor reserved to himself.
It had now become a pressing necessity to protect the left wing of the advancing IInd German Army against the French forces in Alsace, and the IIIrd Army was therefore ordered to cross the frontier on August 4th, without waiting any longer for its trains. The Ist Army, forming the right wing, was in complete readiness near Wadern and Losheim, three or four days' march nearer to the Saar than the IInd Army in the centre. It received the order to concentrate in the neighbourhood of Tholey and there halt for the present. For one thing, this army, the weakest of the three, could not be exposed single-handed to an encounter with the enemy's main force; and for another, it was available to serve as an offensive flank in case the IInd Army should meet the enemy on emerging from the forest zone of the Palatinate.
In the execution of this order, the Ist Army had so extended its cantonments southward that they trenched on the line of march of the IInd Army, and it had to evacuate the quarters about Ottweiler in favour of the latter. This involved a difficulty, as all the villages to the north were full, and as room had also to be found for the Ist Corps, now advancing by Birkenfeld. General von Steinmetz therefore decided to march his whole army in the direction of Saarlouis and Saarbrücken. The IInd Army, on August 4th, stood assembled ready for action, and received orders to deploy on the farther side of the forest zone of Kaiserslautern.
Combat of Weissenburg.
(August 4th.)
On this day the Corps of the IIIrd Army, consisting of 128 battalions, 102 squadrons, and 80 batteries, which had been assembled in bivouac behind the Klingsbach, crossed the French frontier, marching on a broad front to reach the Lauter between Weissenburg and Lauterburg. This stream affords an exceptionally strong defensive position, but on August 4th only one weak Division and a cavalry brigade of the Ist French Corps covered this point, the main body of that Corps being still on the march towards the Palatinate.
Early in the morning the Bavarians forming the right wing encountered a lively resistance before the walls of Weissenburg, which were too strong to be stormed. But very soon after the two Prussian Corps crossed the Lauter lower down. General von Bose led forward the XIth Corps (which he commanded) with intent to turn the French right flank on the Geisberg, while General von Kirchbach, with the Vth Corps (which he commanded) advanced against the enemy's front. Thirty field-guns were meanwhile massed against the railway station of Weissenburg. It and subsequently the town were taken, after a bloody struggle.