This bold movement, which would have drawn on him sharp censure in case of overthrow, was more than justifiable seeing the discouraged state of the French troops, the supreme need of finding their line of retreat, and the splendid results that must follow on the interception of that retreat. The operations of war must always be attended with risk, and the great commander is he whose knowledge of the principles of strategy enables him quickly to see when the final gain warrants the running of risks, and how they may be met with the least likelihood of disaster.
Alvensleben's advance was in accordance with Moltke's general plan of operations; but that corps-leader, finding the French to be in force between him and Metz, determined to attack them in order to delay their retreat. The result was the battle of August 16, variously known as Vionville, Rezonville, or Mars-la-Tour--a battle that defies brief description, inasmuch as it represented the effort of the Third, or Brandenburg, corps, with little help at first from others, to hold its ground against the onsets of two French corps. Early in the fight Bazaine galloped up, but he did not bring forward the masses in his rear, probably because he feared to be cut off from Metz. Even so, all through the forenoon, it seemed that the gathering forces of the French must break through the thin lines audaciously thrust into that almost open plain on the flank of their line of march. But Alvensleben and his men held their ground with a dogged will that nothing could shatter. In one sense their audacity saved them. Bazaine for a long time could not believe that a single corps would throw itself against one of the two roads by which his great army was about to retreat. He believed that the northern road might also be in danger, and therefore did not launch at Alvensleben the solid masses that must have swept him back towards the Meuse. At noon four battalions of the German 10th corps struggled up from the south and took their share of the hitherto unequal fight.
But the crisis of the fight came a little later. It was marked by one of the most daring and effective strokes ever dealt in modern warfare. At 2 o'clock, when the advance of Canrobert's 6th corps towards Vionville threatened to sweep away the wearied Brandenburgers, six squadrons of the 7th regiment of Cuirassiers with a few Uhlans flung themselves on the new lines of foemen, not to overpower them--that was impossible--but to delay their advance and weaken their impact. Only half of the brave horsemen returned from that ride of death, but they gained their end.
The mad charge drove deep into the French array about Rezonville, and gave their leaders pause in the belief that it was but the first of a series of systematic attacks on the French left. System rather than dash was supposed to characterise German tactics; and the daring of their enemies for once made the French too methodical. Bazaine scarcely brought the 3rd corps and the Guard into action at all, but kept them in reserve. As the afternoon sun waned, the whole weight of the German 10th corps was thrown into the fight about Vionville, and the vanguards of the 8th and 9th came up from Gorze to threaten the French left. Fearing that he might be cut off from Metz on the south--a fear which had unaccountably haunted him all the day--Bazaine continued to feed that part of his lines; and thus Alvensleben was able to hold the positions near the southern road to Verdun, which he had seized in the morning. The day closed with a great cavalry combat on the German left wing in which the French had to give way. Darkness alone put an end to the deadly strife. Little more than two German corps had sufficed to stay the march of an army which potentially numbered in all more than 170,000 men.
On both sides the losses were enormous, namely, some 16,000 killed and wounded. No cannon, standards, or prisoners were taken; but on that day the army of Prince Frederick Charles practically captured the whole of Bazaine's army. The statement may seem overdrawn, but it is none the less true. The advance of other German troops on that night made Bazaine's escape from Metz far more difficult than before, and very early on the morrow he drew back his lines through Gravelotte to a strong position nearer Metz. Thus, a battle, which in a tactical sense seemed to be inconclusive, became, when viewed in the light of strategy, the most decisive of the war. Had Bazaine used even the forces which he had in the field ready to hand he must have overborne Alvensleben; and the arrival of 170,000 good troops at Verdun or Châlons would have changed the whole course of the war. The campaign would probably have followed the course of the many campaigns waged in the valleys of the Meuse and Marne; and Metz, held by a garrison of suitable size, might have defied the efforts of a large besieging army for fully six months. These conjectures are not fanciful. The duration of the food supply of a garrison cut off from the outside world varies inversely with the size of that garrison. The experiences of armies invading and defending the East of France also show with general accuracy what might have been expected if the rules of sound strategy had been observed. It was the actual course of events which transcended experience and set all probabilities at defiance.
The battle of Gravelotte, or St. Privat, on the 18th completed the work so hardily begun by the 3rd German corps on the 16th. The need of driving back Bazaine's army upon Metz was pressing, and his inaction on the 17th gave time for nearly all the forces of the First and Second German Armies to be brought up to the German positions, some nine miles west of Metz, though one corps was left to the east of that fortress to hinder any attempt of the French to break out on that side. Bazaine, however, massed his great army on the west along a ridge stretching north and south, and presenting, especially in the southern half, steep slopes to the assailants. It also sloped away to the rear, thus enabling the defenders (as was the case with Wellington at Waterloo) secretly to reinforce any part of the line. On the French left wing, too, the slopes curved inward, thus giving the defenders ample advantage against any flanking movements on that side. On the north, between Amanvillers and Ste. Marie-aux-Chênes, the defence had fewer strong points except those villages, the Jaumont Wood, and the gradual slope of the ground away to the little River Orne, which formed an open glacis. Bazaine massed his reserves on the plateau of Plappeville and to the rear of his left wing; but this cardinal fault in his dispositions--due to his haunting fear of being cut off from Metz--was long hidden by the woods and slopes in the rear of his centre. The position here and on the French left was very strong, and at several parts so far concealed the troops that up to 11 A.m. the advancing Germans were in doubt whether the French would not seek to break away towards the north-west. That so great an army would remain merely on the defensive, a course so repugnant to the ardour of the French nature and the traditions of their army, entered into the thoughts of few.
Yet such was the case. The solution of the riddle is to be found in Bazaine's despatch of August 17 to the Minister of War: "We are going to put forth every effort to make good our supplies of all kinds in order to resume our march in two days if that is possible[41]." That the army was badly hampered by lack of stores is certain; but to postpone even for a single day the march to Verdun by the northern road--that by way of Briey--was fatal. Possibly, however, he hoped to deal the Germans so serious a blow, if they attacked him on the 18th, as to lighten the heavy task of cutting his way out on the 19th.
If so, he nearly succeeded. The Germans were quite taken aback by the extent and strength of his lines. Their intention was to outflank his right wing, which was believed to stretch no further north than Amanvillers; but the rather premature advance of Manstein's 9th corps soon drew a deadly fire from that village and the heights on either side, which crushed the artillery of that corps. Soon the Prussian Guards and the 12th corps began to suffer from the fire poured in from the trenches that crowned the hill. On the German right, General Steinmetz, instead of waiting for the hoped-for flank attack on the north to take effect, sent the columns of the First Army to almost certain death in the defile in front of Gravelotte, and he persisted in these costly efforts even when the strength of the French position on that side was patent to all. For this the tough old soldier met with severe censure and ultimate disgrace. In his defence, however, it may be urged that when a great battle is raging with doubtful fortunes, the duty of a commander on the attacking side is to busy the enemy at as many points as possible, so that the final blow may be dealt with telling