The breach widened under the heavy fire kept up continuously upon it by the French batteries, and as it was evident that other assaults would be made at that spot, the engineers began to throw out a ravelin, or advanced work, from the foot of the walls on each side of the breach, so as to take any assaulting party in flank. On the 1st of May the French, thinking that the breach must now be practicable, advanced for the fourth time.