On the 28th Napoleon, who had from the beginning announced his intention to lead the army, left Paris with the prince imperial, and proceeded to Metz to take the actual command, having on the 23d appointed the empress regent of France during his absence. On the day of his arrival at Metz he issued a proclamation to the troops. On July 31 King William left Berlin for the field, accompanied by his chief political and military advisers, Bismarck and Moltke; he also issued proclamations of encouragement, one to the people of Germany, the other to the army. On Aug. 2 he established his headquarters temporarily at Mentz. On the same day active hostilities began with the attack by three French divisions of Frossard's corps upon the garrison of Saarbruck, about 1,300 men, who were speedily driven back; they retreated across the Saar to St. Johann, while the French occupied the heights before the first named town. But the results of the engagement were unimportant, nor did the French use even the slight advantage they had gained.

Immediately afterward the three German armies began an advance, in which (as the general line of direction pursued tended toward the line of the Moselle and the French centre) the third army took the initiative, inasmuch as it, being the most southerly in position, had the most ground to traverse in executing the contemplated movement. Beginning the march on Aug. 4 from their position east of Landau, the forces of the crown prince pressed forward unmolested as far as the neighborhood of Weissenburg. Here their advance guard was attacked by the French under Gen. Abel Douay, and the first serious conflict of the war began; ending, after five hours of fighting, with the' retreat of the French, who lost their general, while the Germans occupied their abandoned position. On the 5th they continued the advance to Sulz. MacMahon, meanwhile, with the main body of his command, of which Douay's division had been but an advance guard, took up his position at Worth, and prepared for battle. On the morning of the 6th the greater part of the crown prince's forces had so far pushed forward that the armies stood opposing one another, and the German advance guard met the French left wing near Gorsdorf, somewhat northwest of the position of the centre.

The engagement that ensued there became gradually general, and spread along the whole line of the opposing armies. Worth. Elsass-hausen, and Froschweiler, the main points of MacMahon's position, were carried after desperate resistance, and the defeat of the French terminated, shortly after four in the afternoon, in a retreat, and finally almost in a panic, the scattered forces fleeing through the passes of the Vosges, pursued by the German cavalry. The crown prince at once continued his march toward a junction with the other branches of the German army. While these events had happened in the march of the crown prince's forces, the armies of Steinmetz (first army) and Prince Frederick Charles (second army) had effected their junction, advanced across the Saar, occupied Saarbruck, and, on Aug. 6, in the neighborhood of Saarbruck and Forbach, after a most bloody conflict for the possession of the French position on the heights of Spi-chern, had won another complete victory, driving Frossard both from his first line of battle and from the position he afterward endeavored to take up near St. Avoid. The remnants of his corps retreated toward Metz, where Ba-zaine's corps was also joined by Ladmirault's from Thionville, and by troops under Bourbaki and Canrobert. The three German armies were now not long in effecting their junction upon French territory.

The first and second carried on their gradual advance; while the third passed through the Vosges, taking Lutz-elstein and Lichtenberg after short resistance, and leaving Bitsch and Pfalzburg surrounded by detachments of troops. By the 11th the three armies were together, forming an almost unbroken line. The headquarters were established in Saarbruck. By the 14th the first German army had advanced to the immediate neighborhood of Metz; and there, in the afternoon of that day, by a successful attack upon the 3d French corps, which had been sent out to cover the withdrawal of troops from the fortress, baffled the first attempt of the French to retreat to the line of the Marne. The engagement, which took place near Courcelles, and gradually assumed larger proportions, ended with the retreat of the French troops into the fortifications, and secured to the forces of Prince Frederick Charles the necessary time to take up a position for cutting off the French army concentrated at Metz, which Napoleon now left under the chief command of Bazaine, from junction with other French forces.

On the evening of the 15th the 3d corps of Prince Frederick Charles's command took up their, march toward the river, crossed it, and pressed northward as far as the villages of Gorze and Orville. The next morning the march was continued as far as the neighborhood of Mars-la-Tour and Vionville. Here began, about 10 A. M. on the 16th, the engagement which proved to be the most bloody and sharply contested struggle of the war thus far. Beginning by an attack by the Germans upon the much superior force of the enemy which had been encamped at this point, and sustained for hours by the 3d corps alone until the 10th corps and Prince Frederick Charles advanced to its aid in the afternoon, the battle ended in the defeat of the French, though with an immense loss of men to the German army. Bazaine now withdrew his troops to a considerable distance, took up a position between Gravelotte and St. Privat-la-Montagne, and there massed almost his whole force, preparatory to a final and decisive engagement. For this the Germans also made ready, and on the 18th the hotly contested battle of Gravelotte began, ending in a renewed defeat of the French, and in their retreat within the fortifications of Metz. The results of this engagement were most important.