The next lunette to the left, No. 52, was merely an earthwork, and the attack had already been pushed forward as far as the edge of the ditch, but earth screens had first to be thrown up and covered in with railway iron, as a protection against the heavy fire of shell from bastion No. 12. The construction of a dam of fascines or earth, more than sixty paces across, and with the ditch full of water almost fathom deep, would have taken a long time; so it was decided to make a cask bridge of beer-barrels, of which a quantity had been found in Schiltigheim. This work was begun at dusk on the 21st, under no better protection than a screen of boards to prevent observation, and it was finished by ten o'clock. Here again the defenders had not waited for the escalade, and this lunette, too, was immediately prepared for being held. Both lunettes were now furnished with batteries of mortars and guns to silence the fire from the ravelines and counter-guards of the front of attack, against which five dismounted and counter-batteries were also directed.
During the night of the 22nd--23rd the Germans advanced from lunette No. 52, partly by flying sap and partly by the deep sap, and there followed the crowning of the glacis in the front of counter-guard No. 51. A breaching fire was immediately opened against the east face of bastion No. 11, and the west face of bastion No. 12. The splinters of stone compelled the defenders to abandon the counter-guards. The scarp of bastion No. 11 fell on the 24th, after a shell-fire of 600 rounds. The bringing down of the earthwork angle which remained standing, was postponed till the beginning of the assault.
It was more difficult to breach bastion No. 12, because of the limited opportunity for observing the effect of the fire. It was not till the 26th that a breach thirty-six feet wide was made, after firing 467 long shells. And even then, for the actual assault to succeed, the deep wet ditch at the foot of the bastion had to be crossed.
News of the fall of the Empire had indeed reached Strasburg, but General Uhrich would not listen to the prayers of the citizens that he would put an end to their sufferings. The Republic was proclaimed.
The siege had lasted thirty days, but the place was still well supplied with food and stores; the garrison was not materially weakened by the loss of 2500 men, but its heterogeneous elements prevented its effective employment in large bodies outside the walls. From the first the small blockading force had been allowed to approach close to the works; and the moment when the artillery of a fortress always has the advantage over the attack had been little utilized.