On the surrender of the town, no time was lost in prosecuting operations against the citadel, and the line of circumvallation was traced out that very evening. But this undertaking proved more difficult than had been expected, and several weeks elapsed before any material progress was made in the operations, during which Villars made good use of his time in completing his new lines to cover Valenciennes and Condé. The garrison of the citadel, though unequal to the defence of the town of Tournay, was quite adequate to that of the citadel: and the vast mines with which the whole outworks and glacis were perforated, rendered the approaches in the highest degree perilous and difficult. The governor, M. De Surville, proposed, on the 5th August, to capitulate in a month if not relieved; and to this proposition, Marlborough and Eugene with praiseworthy humanity at once acceded: but the King of France refused to ratify the terms proposed, unless the suspension of arms was made general to the whole Netherlands, to which the allied general would not accede. The military operations consequently went on, and soon acquired a degree of horror hitherto unparalleled even in that long and bloody contest. The art of countermining, and of counteracting the danger of mines exploding, was then very imperfectly understood, though that of besieging above ground had been brought to the very highest degree of perfection. The soldiers, in consequence, entertained a great and almost superstitious dread of the perils of that subterraneous warfare, where prowess and courage were alike unavailing, and the bravest, equally as the most pusillanimous, were liable to be at any moment blown into the air, or smothered under ground, by the explosions of an unseen, and therefore appalling, enemy. The Allies were inferior in regular sappers and miners to the besieged, who were singularly well supplied with that important arm of the service. The ordinary soldiers, how brave soever in the field, evinced a repugnance at engaging in this novel and terrific species of warfare: and it was only by personally visiting the trenches in the very hottest of the fire, and offering high rewards to the soldiers who would enter into the mines, that men could be got who would venture on the perilous service.22
It was not surprising that even the bravest of the allied troops were appalled at the new and extraordinary dangers which now awaited them, for they were truly of the most formidable description. What rendered them peculiarly so, was, that the perils in a peculiar manner affected the bold and the forward. The first to mount a breach, to effect a lodgement in a horn-work, to penetrate into a mine, was sure to perish. First a hollow rumbling noise was heard, which froze the bravest hearts with horror: a violent rush as of a subterraneous cataract succeeded; and immediately the earth heaved, and whole companies, and even battalions, were destroyed with a frightful explosion. On the 15th August a sally by M. De Surville was bravely repulsed, and the besiegers, pursuing their advantage, effected a lodgement in the outwork: but immediately a mine was sprung, and a hundred and fifty men were blown into the air. In the night between the 16th and 17th, a long and furious conflict took place below ground and in utter darkness, between the contending parties, which at length terminated to the advantage of the besiegers.23 On the 23d a mine was discovered, sixty feet long by twenty broad, which would have blown up a whole battalion of Hanoverian troops placed above it; but while the Allies were in the mine, congratulating themselves on the discovery, a mine below it was suddenly sprung, and all within the upper one buried in the ruins. On the night of the 25th, three hundred men, posted in a large mine discovered to the Allies by an inhabitant of Tournay, were crushed by the explosion of another mine directly below it; and on the same night, one hundred men posted in the town ditch were suddenly buried under a bastion blown out upon them. Great was the dismay which these dreadful and unheard-of disasters produced among the allied troops. But at length the resolution and energy of Marlborough and Eugene triumphed over every obstacle. Early on the morning of the 31st August the white flag was displayed, and a conference took place between the two commanders in the house of the Earl of Albemarle; but the governor having refused to accede to the terms demanded – that he should surrender prisoners of war – the fire recommenced, and a tremendous discharge from all the batteries took place for the next three days. This compelled the brave De Surville to submit; and Marlborough, in consideration of his gallant defence, permitted the garrison to march out with the honours of war, and return to France, on condition of not serving again till exchanged. On September 3d the gates were surrendered; and the entire command of this strong fortress and rich city, which entirely covered Spanish Flanders, was obtained by the Allies.24
No sooner was Tournay taken than the allied generals turned their eyes to Mons, the next great fortress on the road to Paris, and which, with Valenciennes, constituted the only remaining strongholds that lay on that line between them and Paris. So anxious was Marlborough to hasten operations against this important town, that on the very day on which the white flag was displayed from the citadel of Tournay, he dispatched Lord Orkney with all the grenadiers of the army, and twenty squadrons, to surprise Ghislain, and secure the passage of the Haine. On the 3d, the Prince of Hesse-Cassel was dispatched after him with 4000 foot and 60 squadrons. Lord Orkney, on arriving on the banks of the Haine, found the passage so strongly guarded that he did not deem it prudent to alarm the enemy by attempting to force them. The Prince of Hesse-Cassel, however, was more fortunate. He marched with such extraordinary diligence, that he got over forty-nine English miles in fifty-six successive hours; a rapidity of advance, for such a distance, that had never been surpassed at that, though it has been outdone in later times.25 By this means he reached the Haine on the other side of Mons, and surprised the passage near Obourg, at two in the morning of the 6th, and at noon he entered the French lines of the Trouille without opposition, the enemy retiring with precipitation as he advanced. He immediately extended his forces over the valley of the Trouille, fixed his headquarters at the abbey of Belian, and with his right occupied in strength the important plateau of Jemappes, which intercepted the communication between Mons and Valenciennes. It was on this height that the famous battle was fought between the French Republicans under Dumourier in 1792: another proof among the many which history affords how frequently the crisis of war, at long distances of time from each other, takes place in the same place. By this decisive movement Marlborough gained an immense advantage; – Mons was now passed and invested on the side of France; and the formidable lines, thirty leagues in length, on which Marshal Villars had been labouring with such assiduity during the two preceding months, were turned and rendered of no avail.26
While the Prince of Hesse-Cassel, with the advanced guard of the army, gained this brilliant success, Marlborough was rapidly following with the main body in the same direction. The force besieging Tournay crossed the Scheldt at the bridge of that town, and joined the covering force under Eugene. From thence they advanced to Sirant, where they were joined by Lord Orkney with his detachment, which had failed in passing the Haine. On the 6th, having learned of the success of the Prince of Hesse-Cassel, who had turned the enemy's lines, and got between Mons and France, the allied generals pushed on with the utmost expedition, and leaving their army to form the investment of Mons, joined the prince in the abbey of Belian. Both commanders bestowed on him the highest compliments for the advantages he had gained; but he replied, "The French have deprived me of the glory due to such a compliment, since they have not even waited my arrival." In truth, such had been the celerity and skill of his dispositions, that they had rendered resistance hopeless, and achieved success without the necessity of striking a blow. Meanwhile Marshal Boufflers, hearing a battle was imminent, arrived in the camp as a volunteer, to serve under Villars, his junior in military service; a noble example of disinterested