Moving majestically forward, with leisurely deliberation, that seemed to show the consciousness of superior strength, and a steady purpose of doing their work thoroughly, the Allies appeared before Longwy on the 20th of August, and the dispirited and dependent garrison opened the gates of that fortress to them after the first shower of bombs. On the 2d of September the still more important stronghold of Verdun capitulated after scarcely the shadow of resistance.
Brunswick's superior force was now interposed between Kellerman's troops on the left, and the other French army near Sedan, which La Fayette's flight had, for the time, left destitute of a commander. It was in the power of the German general, by striking with an overwhelming mass to the right and left, to crush in succession each of these weak armies, and the allies might then have marched irresistible and unresisted upon Paris. But at this crisis Dumouriez, the new commander-in-chief of the French, arrived at the camp near Sedan, and commenced a series of movements, by which he reunited the dispersed and disorganized forces of his country, checked the Prussian columns at the very moment when the last obstacles of their triumph seemed to have given way, and finally rolled back the tide of invasion far across the enemy's frontier.
The French fortresses had fallen; but nature herself still offered to brave and vigorous defenders of the land, the means of opposing a barrier to the progress of the Allies. A ridge of broken ground, called the Argonne, extends from the vicinity of Sedan towards the south-west for about fifteen or sixteen leagues, The country of L'Argonne has now been cleared and drained; but in 1792 it was thickly wooded, and the lower portions of its unequal surface were filled with rivulets and marshes. It thus presented a natural barrier of from four to five leagues broad, which was absolutely impenetrable to an army, except by a few defiles, such as an inferior force might easily fortify and defend. Dumouriez succeeded in marching his army down from Sedan behind the Argonne, and in occupying its passes, while the Prussians still lingered on the north-eastern side of the forest line. Ordering Kellerman to wheel round from Metz to St. Menehould, and the reinforcements from the interior and extreme north also to concentrate at that spot, Dumouriez trusted to assemble a powerful force in the rear of the south-west extremity of the Argonne, while, with the twenty-five thousand men under his immediate command, he held the enemy at bay before the passes, or forced him to a long circumvolution round one extremity of the forest ridge, during which, favourable opportunities of assailing his flank were almost certain to occur. Dumouriez fortified the principal defiles, and boasted of the Thermopylae which he had found for the invaders; but the simile was nearly rendered fatally complete for the defending force. A pass, which was thought of inferior importance, had been but slightly manned, and an Austrian corps under Clairfayt, forced it after some sharp fighting. Dumouriez with great difficulty saved himself from being enveloped and destroyed by the hostile columns that now pushed through the forest. But instead of despairing at the failure of his plans, and falling back into the interior, to be completely severed from Kellerman's army, to be hunted as a fugitive under the walls of Paris by the victorious Germans, and to lose all chance of ever rallying his dispirited troops, he resolved to cling to the difficult country in which the armies still were grouped, to force a junction with Kellerman, and so to place himself at the head of a force, which the invaders would not dare to disregard, and by which he might drag them back from the advance on Paris, which he had not been able to bar. Accordingly, by a rapid movement to the south, during which, in his own words, "France was within a hair's-breadth of destruction," and after, with difficulty, checking several panics of his troops in which they ran by thousands at the sight of a few Prussian hussars, Dumouriez succeeded in establishing his head-quarters in a strong position at St. Menehould, protected by the marshes and shallows of the river Aisne and Aube, beyond which, to the north-west, rose a firm and elevated plateau, called Dampierre's Camp, admirably situated for commanding the road by Chalons to Paris, and where he intended to post Kellerman's army so soon as it came up. [Some late writers represent that Brunswick did not wish to check Dumouriez. There is no sufficient authority for this insinuation, which seems to have been first prompted by a desire to soothe the wounded military pride of the Prussians.]
The news of the retreat of Dumouriez from the Argonne passes, and of the panic flight of some divisions of his troops, spread rapidly throughout the country; and Kellerman, who believed that his comrade's army had been annihilated, and feared to fall among the victorious masses of the Prussians, had halted on his march from Metz when almost close to St. Menehould. He had actually commenced a retrograde movement, when couriers from his commander-in-chief checked him from that fatal course; and then continuing to wheel round the rear and left flank of the troops at St. Menehould, Kellerman, with twenty thousand of the army of Metz, and some thousands of volunteers who had joined him in the march, made his appearance to the west of Dumouriez, on the very evening when Westerman and Thouvenot, two of the staff-officers of Dumouriez, galloped in with the tidings that Brunswick's army had come through the upper passes of the Argonne in full force, and was deploying on the heights of La Lune, a chain of eminences that stretch obliquely from south-west to north-east opposite the high ground which Dumouriez held, and also opposite, but at a shorter distance from, the position which Kellerman was designed to occupy.
The Allies were now, in fact, nearer to Paris than were the French troops themselves; but, as Dumouriez had foreseen, Brunswick deemed it unsafe to march upon the capital with so large a hostile force left in his rear between his advancing columns and his base of operations. The young King of Prussia, who was in the allied camp, and the emigrant princes, eagerly advocated an instant attack upon the nearest French general. Kellerman had laid himself unnecessarily open, by advancing beyond Dampierre's Camp, which Dumouriez had designed for him, and moving forward across the Aube to the plateau of Valmy, a post inferior in strength and space to that which he had left, and which brought him close upon the Prussian lines, leaving him separated by a dangerous interval from the troops under Dumouriez himself. It seemed easy for the Prussian army to overwhelm him while thus isolated, and then they might surround and crush Dumouriez at their leisure.
Accordingly, the right wing of the allied army moved forward, in the grey of the morning of the 20th of September, to gain Kellerman's left flank and rear, and cut him off from retreat upon Chalons, while the rest of the army, moving from the heights of La Lune, which here converge semi-circularly round the plateau of Valmy, were to assail his position in front, and interpose between him and Dumouriez. An unexpected collision between some of the advanced cavalry on each side in the low ground, warned Kellerman of the enemy's approach. Dumouriez had not been unobservant of the danger of his comrade, thus isolated and involved; and he had ordered up troops to support Kellerman on either flank in the event of his being attacked. These troops, however, moved forward slowly; and Kellerman's army, ranged on the plateau of Valmy, "projected like a cape into the midst of the lines of the Prussian bayonets." [See Lamartine, Hist. Girond. livre xvii. I have drawn much of the ensuing description from him.] A thick autumnal mist floated in waves of vapour over the plains and ravines that lay between the two armies, leaving only the crests and peaks of the hills glittering in the early light. About ten o'clock the fog began to clear off, and then the French from their promontory saw emerging from the white wreaths of mist, and glittering in the sunshine, the countless Prussian cavalry which were to envelops them as in a net if once driven from their position, the solid columns of the infantry that moved forward as if animated by a single will, the bristling batteries of the artillery, and the glancing clouds of the Austrian light troops, fresh from their contests with the Spahis of the east.
The best and bravest of the French must have beheld this spectacle with secret apprehension and awe. However bold and resolute a man may be in the discharge of duty, it is an anxious and fearful thing to be called on to encounter danger among comrades of whose steadiness you can feel no certainty. Each soldier of Kellerman's army must have remembered the series of panic routs which had hitherto invariably taken place on the French side during the war; and must have cast restless glances to the right and left, to see if any symptoms of wavering began to show themselves, and to calculate how long it was likely to be before a general rush of his comrades to the rear would either harry him off with involuntary disgrace, or leave him alone and helpless, to be cut down by assailing multitudes.
On that very morning, and at the self-same hour, in which the allied forces and the emigrants began to descend from La Lune to the attack of Valmy, and while the cannonade was opening between the Prussian and the Revolutionary batteries, the debate in the National Convention at Paris commenced on the proposal to proclaim France a Republic.
The old monarchy had little chance of support in the hall of the Convention; but if its more effective advocates at Valmy had triumphed, there were yet the elements existing in France for a permanent revival of the better part of the ancient institutions, and for substituting Reform for Revolution. Only a few weeks before, numerously signed addresses from the middle classes in Paris, Rouen, and other large cities, had been presented to the king, expressive of their horror of the anarchists, and their readiness to uphold the rights of the crown, together with the liberties of the subject. And an armed resistance to the authority of the Convention, and in favour of the king, was in reality at this time being actively organized in La Vendee and Brittany, the importance of which may be estimated from the formidable opposition which the Royalists of these provinces made to the Republican party, at a later period, and under much more disadvantageous circumstances. It is a fact peculiarly illustrative of the importance of the battle of Valmy, that "during the summer of 1792, the gentlemen of Brittany entered into an extensive association for the purpose of rescuing the country from the oppressive yoke which had been imposed by the Parisian demagogues. At the head of the whole was the Marquis de la Rouarie, one of those remarkable men who rise into pre-eminence during the stormy days of a revolution, from conscious ability to direct its current. Ardent, impetuous, and enthusiastic, he was first distinguished in the American war, when the intrepidity of his conduct attracted the admiration of the Republican troops, and the same qualities rendered him at first an ardent supporter of the Revolution in France; but when the atrocities of the people began, he espoused with equal warmth the opposite side, and used the utmost efforts to rouse the noblesse of Brittany against the plebeian yoke which had been imposed upon them by the National Assembly. He submitted his plan to the Count d'Artois, and had organized one so extensive, as would have proved extremely formidable to the Convention, if the retreat of the Duke of Brunswick, in September 1792, had not damped the ardour of the whole of the west of France, then ready to break out into insurrection." [Alison, vol. iii. p. 323.]
And it was not only among the zealots of the old monarchy that the cause of the king would then have found friends. The ineffable atrocities of the September massacres had just occurred, and the reaction produced by them among thousands who had previously been active on the ultra-democratic side, was fresh and powerful. The nobility had not yet been made utter aliens in the eyes of the nation by long expatriation and civil war. There was not yet a generation of youth educated in revolutionary principles, and knowing no worship-save that of military glory, Louis XVI. was just and humane, and deeply sensible of the necessity of a gradual extension of political rights among all classes of his subjects. The Bourbon throne, if rescued in 1792, would have had chances of stability, such as did not exist for it in 1814, and seem never likely to be found again in France.