The night of the 13th and 14th was passed in much agitation by the garrison and inhabitants. Several of the public buildings were set fire to and burned by grenades. The works of the besiegers were now greatly advanced. The garrison made five sorties in this night, and were repulsed in all, losing an hundred men, while the besiegers lost eight killed and one-and-thirty wounded.

On the 14th of July, a cessation of arms took place from seven o'clock in the morning till one. In the city, the French celebrated their annual fête; General d'Oyré and the troops took the oath, and Merlin delivered an address to them. In the Austrian camp, the Prince de Condé was received with a feu de joye. During this cessation, the soldiers upon the different outposts entered into conversation with each other, and the French boasted of the difficulties they laboured under from the length of the siege.

At night, an affair at the Fleche cost the allies, who succeeded in part, ninety men; the French confessed, that this work cost them in all three hundred. The inhabitants of the city were again greatly alarmed, their streets being covered with a shower of grenades. The laboratory and a part of the Benedictine abbey were burned, and two explosions took place at the former. The whole city shook with each report, and, in the nearer parts, all the windows were broken and the doors burst open. The remainder of the hay and straw was consumed in this fire; the whole stock of other forage was reduced to a sufficiency for four days; and the surgeon's stores were much damaged.

Still the Fleche prevented the besiegers from completing their second parallel. It was, therefore, again attacked, on the night of the 16th and 17th, Prince Louis Ferdinand of Prussia commanding at the assault, in which he was one of twelve officers wounded. The Fleche was then completely carried.

The next night was very industriously spent by the besiegers in forming new batteries, and those of the second parallel were raised, before there were cannon enough at hand to place upon them. The French took advantage of this, and brought a part of theirs to bear, so as to enfilade the parallel, with great effect; the Prussians almost immediately losing an officer and forty men.

In the city, the sick had now increased so much, that six hundred men were brought from Cassel, on the 17th, to re-inforce the garrison. On the 18th, the commandant informed the Council, that there was a want of fodder and such a loss of horses, by desertion, that there were not cavalry enough left for service. The soldiers, who knew the deficiency of medicines and other means of relief for the wounded, were unwilling to be led to sorties. Though corn had not failed, flour, it appeared, soon would, for some of the mills had been rendered unserviceable, for the present, by shot, and others were deserted by the millers.

At night, after an unsuccessful attempt upon the Fleche, it was resolved, that the garrison, which had hitherto scarcely suffered a night to pass, without making some sorties, should, for the future, adhere solely to defensive measures. Some engineers proposed to abandon the whole line of forts, and others, that two of the largest should be blown up. The General and Council, at length, confessed, that they could not continue the defence, and assured the inhabitants, who had declared themselves in their favour, that a longer delay of the surrender would produce a more severe disposition of the besiegers towards them, without increasing the chance of escaping it.

A negotiation, relative to the surrender, was now begun by D'Oyré, in a letter, which partly replied to one from the Prussian commander Kalkreuth, upon the subject of the departure of aged persons and children from the city. Their correspondence continued till the 20th, and several letters were exchanged, chiefly upon the question of the removal, or detention of the inhabitants, who had attached themselves to the French; it was then broken off, upon a disagreement, as to this and some other points. The firing, on both sides, had in the mean time continued, and the besiegers carried on the trenches, though these were now such an easy mark for the garrison, that they lost an officer and five-and-twenty men, in the night of the 19th and 20th. The next night, the Dominicans' church in the city took fire, and six French soldiers were buried under its ruins.

Upon a renewal of the intercourse, the fire slackened, on the 21st; but, on some delays in the negotiation, was threatened to be recommenced. At length, the conditions of the surrender were settled, and the negotiation signed, on the 22d of July, by the two Generals Kalkreuth and D'Oyré; the former having rendered the capitulation somewhat easier than was expected for the garrison, because the Duke of Brunswick had only nineteen thousand men to cover the siege, and Custine had forty thousand, which were near enough to attack him. General Kalkreuth's orders are supposed to have been to obtain possession of the place, upon any terms, that would give it him quickly.

At this time, the garrison, which, at the commencement of the siege, had consisted of 22,653 men, was reduced to 17,038, having had 1959 killed, 3334 wounded, or rendered unserviceable by sickness, and having lost 322 by desertion.