All the palisades were broken down and the block houses ruined. The ditch filled up with mud. Captain Treat and his lieutenant were killed. Colonel Smith was wounded and the garrison nearly exhausted.
Major Thayer with some New England troops relieved the garrison. Major Fleury would not be relieved and remained with the garrison.
On November 15 the enemy made a furious attack by the river and land and floating batteries on the fort.
The ships came as near the fort as possible in the main channel, and the Vigilant, carrying 24-pounders, came up under the protection of the land batteries, behind Hog Island, and anchored forty yards from the angle of the battery.
Fort Mifflin had been so much exposed on that side that on it did not remain a single gun. Major Thayer ordered the 32-pounder to be carried there. Before the Vigilant began to fire that single gun put fourteen shots in her board. But as soon as she was at anchor and began to play all resistance became impossible.
In three or four broadsides not only the parapet and the carriages but even the irons of the guns themselves were broken, and in half an hour not a gun in the fort was able to fire.
Another sloop of war joined the Vigilant and played against the fort all the afternoon.
The garrison was buried in ruins, unable to retreat during the day and unwilling to do it as long as they could expect re-enforcements, had not any expectation but to sell their lives dearly as they could.
It was impossible to defend the fort with so small a force, and Major Thayer called for re-enforcements from Fort Mercer or he must evacuate the fort. At that moment Major Fleury and Major Talbot were wounded and another officer of artillery killed.
At 10 o’clock at night, as no re-enforcements had arrived from New Jersey, it was impossible to defend the fort any longer.