Before the storm of the fort was attempted Colonel Donop sent a flag to Colonel Christopher Green, who commanded the fort, threatening to put the garrison to the sword if he did not surrender it immediately. Colonel Green answered with disdain, saying he would defend it till the last drop of his blood. About an hour before night the attack was begun on the north and south side.
Both the British attacks were expected. The artillery and musketry of the fort and the heavy guns of the galleys poured grapeshot and cannon balls upon them and made great slaughter. They advanced as far as the abattis, and being repulsed with great loss, they left their commanding officer dying and retreated with hurry and confusion. They rallied in the woods, and leaving their wounded and dead, about 300, in the hands of the victors, retired to Philadelphia the same night.
Colonel Green and the officers who had displayed so much courage in repulsing the enemy, treated the wounded with much humanity. Colonel Donop was attended with the greatest care, but he died a few days after the action, and was buried with the honors of war.
The morning after the attack on Fort Mercer it became Fort Mifflin’s turn. On the 22d, about 9 o’clock, the ships Eagle, Somerset, Isis, Augusta, Pearl, Liverpool and several frigates, with a galley, came up to the chevaux de frise, 500 yards from the fort. At the same time the land batteries, the fort batteries and the American galleys and the British squadron engaged.
The firing continued until noon with relentless fury; the fort frequently fired red-hot balls, one of which struck the Augusta, a sixty-four-gun ship, she took fire, and in a moment was ablaze, and soon after blew up with a thundering noise, before the enemy could take out all their hands.
A moment after, the Merlin, a twenty-two-gun frigate, ran ashore below the Augusta, and as she could not be removed before the explosion, took fire and also blew up.
The other ships, frightened by the fate of these two, retired below Hog Island; and the land batteries, which had hoisted the bloody flag, to warn the garrison that they were not to expect any quarter, continued their fighting until evening.
The weakened garrison had been re-inforced by Pennsylvania and Virginia troops, but Colonel Smith found the garrison in great danger from fatigue and salt provisions, the water they had to wade through, the cold nights and constant firing by the enemy turned many men to the hospital.
The enemy suffered also from the inclemency of the weather, and the overflowing of the island. The water was two feet deep in their fort.
The British, believing they must evacuate Philadelphia or take the fort, made new batteries, and on November 8 kept up an incessant fire.