When Marshal MacMahon evacuated Alsace, only three battalions of the line were left with the commandant of Strasburg. But with stragglers from the various regiments engaged at Wörth, with sundry fourth battalions and reserve detachments, and finally with Mobiles and National Guards, the strength of the garrison had increased to 23,000 men. There was a complete absence of engineer troops, but 130 marines formed an excellent nucleus; the armament of the fortress was also ample.
So early as on the 11th August the Baden Division had been detailed to observe Strasburg. Notwithstanding the smallness of its force the Division had advanced unchecked by the enemy on the Ruprechtsau as far as the Rhine-and-Ill Canal; had occupied the village of Schiltigheim, almost within rifle-shot of the fortifications: and, having promptly prepared it for defence, pushed forward into the suburb of Königshofen.
In the course of eight days there arrived, under the command of General von Werder, the Guard Landwehr and 1st Reserve Divisions, and one cavalry brigade, in all 46 battalions, 24 squadrons, and 18 field-batteries; as well as a siege-train of 200 rifled cannon and 88 mortars, with 6000 foot artillerymen and ten companies of fortress-pioneers; a total strength of 40,000 men.
The unloading of the guns brought from Magdeburg, Coblentz, and Wesel was begun on August 18th at the railway station of Vendenheim, by a detachment of the Railway Battalion.
The engineer-depôt was established at Hausberge, a wagon-park at Lampertsheim, and provision made for permanent magazines. A complete blockade was established, and the field-telegraph kept up communication between all the posts.
To attain the desired end with the least possible delay, an attempt was made, contrary to the advice of General of Engineers Schultz, though with the sanction of the supreme Head-quarter, to force the town to surrender by stress of a bombardment. The request that the women and children should be allowed to withdraw was necessarily refused.
The erection of the batteries for the bombardment in the dark, wet nights was attended with great difficulties. Meanwhile only the field-guns could fire on the city; but the batteries whose armament of heavy guns was complete opened fire on the night of the 24th--25th; and soon a great fire was raging. Kehl, on the right bank of the river, was also set on fire by the shell-fire.
