Look at the map on page 98, and find, to the south of the Vosges Mountains, the great French fortress of Belfort. From this place you will see a little plain across which an army can move easily to the Upper Rhine. While the Germans were advancing on Liége, French airmen flew across the plain and discovered that only a few of the enemy's troops were on the left bank of the Rhine. The French thereupon determined to occupy the country up to the left bank of the river. On the evening of Friday, 7th August, the day on which von Emmich asked General Leman for a truce so that he might bury his dead, a French brigade marched out of Belfort and crossed the frontier. Just before sunset it reached the little town of Altkirch, about a dozen miles inside German territory, and there found small bodies of Germans lining the trenches and awaiting an attack. The French infantry advanced with great spirit, carried the trenches, and by bayonet charges put the Germans to flight. Cavalry at once followed up the retreating enemy, and worked great havoc on them. Then the French entered Altkirch, bearing before them the tricolour. The townsfolk rushed out of their houses to welcome them, and when they saw the flag under which they had lived and prospered forty-four years ago, they raised cheer after cheer. Already some of the villagers on the frontier had torn up the poles which marked the border-line between France and Germany. In less than an hour the French were on the outskirts of Mulhouse, the largest and most important manufacturing town of Alsace, nine miles to the north of Altkirch. The people of Mulhouse have always been deeply attached to France. When the town became German in 1871, large numbers of them left their homes and settled in France and Algeria, in order that they might not be severed from the country which they loved so well. Mulhouse was occupied with but little resistance next day, and that evening General Joffre sent out the following message to the people:-- "Children of Alsace,--After forty-four years of sorrowful waiting, French soldiers once more tread the soil of your noble country. They are the pioneers in the great work of revenge. For them, what emotions it calls forth, and what pride! "To complete the work, they have made the sacrifice of their lives. The French nation as one man urges them on, and in the folds of their flag are inscribed the magic words, 'Right and Liberty.' Long live Alsace! Long live France! "General-in-chief of the French Armies, "Joffre."