While one half of the German Army was thus engaged in a victorious advance, the other half remained stationary before Metz.
The foremost line of outposts of the investment embraced a circuit of more than twenty-eight miles. An attempt of the concentrated forces of the enemy to break through would have met at the beginning of the blockade with but slight opposition. It was therefore extremely urgent that the several posts should be strengthened by fortifications. These works, the clearing of the neighbouring battle-fields, the close watch kept over every movement of the enemy, the construction of a telegraph-line connecting the quarters of the several Staffs, and finally the erection of a sufficiency of shelter, kept the troops and their leaders amply occupied. Besides the care of the wounded, provision had to be made for the sick, whose number was daily increased by the unusually severe weather and lack of shelter. The provisioning of the troops was, however, facilitated by their stationary attitude, and in addition there now flowed in upon them from their homes a copious supply of love-gifts.
The first days of the investment went by without any attempts to break out on the part of the French. They too were busy reorganizing, collecting ammunition and supplies.
On the 20th of August Marshal Bazaine had written to Châlons: "I will give due notice of my march if, taking everything into consideration, I can undertake any such attempt." On the 23rd he reported to the Emperor: "If the news of the extensive reductions in the besieging army is confirmed, I shall set out on the march, and that by way of the northern fortresses, in order to risk nothing."
On the 26th of August, when the Army of Châlons was still nearly seventy miles distant from the Ardennes Canal, and its advance on Metz was as yet not generally known, Marshal Bazaine collected his main forces on the right bank of the Moselle.
This movement had not escaped the notice of the German posts of observation, and the field-telegraph at once disseminated the information.
To support the 3rd Reserve Division at Malroy, ten battalions of the Xth Corps crossed from the left bank of the Moselle to Argancy on the right bank. The 25th Division held itself in readiness at the bridge of Hauconcourt, and the Ist Corps closed up towards Servigny. In the event of the success of a breach towards the north, the IIIrd, IVth, and part of the IXth Corps were available to intercept the enemy's march about Thionville.