The French front south of Pont-a-Mousson, on the Moselle, through the gap of Nancy to the tops of the Vosges experienced only slight changes during the spring and summer of 1915. The Germans assumed the offensive in the region of La Fontenelle, in the Ban-de-Sapt, in April and June. The French engineers had built a redoubt to the east of La Fontenelle on Hill 627. The Germans found they could not take it by an assault; so their sappers went to work to tunnel under it; but they had to bore through very hard rock and the work was necessarily slow. The French, learning of the mining operations of their foes, started a countereffort with the result that there was a succession of fierce skirmishes under the surface of the earth. Finally the German sappers were lured into a communicating tunnel which had been mined for the purpose and they all perished. The greatest activity of the sappers was between April 6 and April 13, 1915. On the night of the latter date the officers of the Germans tried to rally their men for further operations, but their soldiers had had enough and refused to renew their work. The Germans, however, did not give up in their attempts to take Hill 627, which they called Ban-de-Sapt, and in an assault they made upon it on June 22 they took the hill. Thereupon the general in command of the Thirtieth Bavarian Division made the following announcement: "I have confidence that the height of Ban-de-Sapt will be transformed with the least possible delay into an impregnable fortification and that the efforts of the French to retake it will be bloodily repulsed." On the night of July 8 the French began a bombardment which was followed by an infantry charge which forced its way through five lines of trenches and gained the redoubt on the top of the hill, in spite of its corrugated iron and gun-shield defenses to which had been added logs and tree trunks. At the same time the French made an attack on the German trenches on the left and surrounded the hill from the eastward. The Germans on the right flank of the French were kept busy by another attack. In this battle two battalions of the Fifth Bavarian Ersatz Brigade were taken from the German ranks either by death or as prisoners. The French captured eight hundred and eighty-one, of whom twenty-one were officers, who, for the most part, were men of more than ordinary education.