The French were trying to take Mulhouse in flank, and they had therefore to capture the village of Cernay, which blocked the way. Meanwhile another force attacked Altkirch, to the south of Mulhouse, and quite close to the Swiss border. During the fighting some of the shells actually fell on Swiss ground. The force advancing from Steinbach could not capture Cernay, so it turned to the south, and tried to seize the village of Burnhaupt in order to attack Mulhouse from another angle. The village was taken by the French; but was retaken, though with heavy loss, by the Germans. Strive as they would, the French could get no nearer to Mulhouse. [Illustration] If you look to the north of Cernay, you will see a spur of the Vosges known as Hartmannsweilerkopf. It stands 2,000 feet above the plain, and consists of rugged rocks covered with pine trees. He who possesses the kopf can command a very large part of the plain, for he can shell many roads and railway lines. The French greatly coveted it, and they had already established a small advance post on it. Let me tell you how this post was lost and won again. Soon after the fighting at Altkirch, violent winter storms began to rage. Snow fell without ceasing for a fortnight, and the upper glens were choked with drifts. When the sky cleared the chasseurs donned their skis and made some daring raids on German posts in the hills. The Germans were active too. On 19th January, during a blinding snowstorm, they climbed Hartmannsweilerkopf and attacked the French post at the summit. Four companies of chasseurs made a most gallant attempt to relieve the defenders, and for two days fought fiercely amidst the icy rocks and snow-laden bushes. They could, however, make no headway, and the post was captured by the Germans on 21st January.