Meanwhile the Fifty-fifth Regiment had been vigorously attacked by St. Clair's brigade, and, after a short action, those who could get away were in full retreat towards New Brunswick. The last regiment, the Fortieth, had not been able to get into action at all; a part of it fled in a panic, with the remains of the Fifty-fifth, towards New Brunswick, hotly pursued by Washington with the Philadelphia City Troop and what cavalry he could muster, and the rest took refuge in the college building in Princeton, from which they were dislodged by artillery and compelled to surrender. The British loss was about five hundred in killed and wounded and prisoners, the American less than one hundred; but among the latter were many valuable officers,--Colonels Haslet and Potter, Major Morris, Captains Shippen, Fleming, Talbot, Neal, and General Mercer.
After following the retiring and demoralized British for a few miles, Washington determined to abandon the pursuit. The men were exhausted by their long and fatiguing marches, and were in no condition to make the long march to New Brunswick; most of them were still ill equipped and entirely unfitted for the fatigue and exposure of a further winter campaign,--even those iron men must have rest at last. The flying British must have informed Leslie's troops, six miles away, of the situation; they would soon be upon them, and they might expect Cornwallis with his whole force at any time. He drew off his troops, therefore, and, leaving a strong party to break down the bridge over Stony Brook and impede the advance of the English as much as possible, he pushed on towards Pluckamin and Morristown, officers and men thoroughly satisfied with their brilliant achievements.
Early in the morning the pickets of Cornwallis' army discovered that something was wrong in the American camp; the guard had been withdrawn, the fires had been allowed to die away, and the place was as still as death. A few adventurous spirits, cautiously crossing the bridge, found that the guns mounted in front of it were only "quakers," and that the whole camp was empty,--the army had decamped silently, and stolen away before their eyes! My Lord Cornwallis, rudely disturbed from those rosy dreams of conquest with which a mocking spirit had beguiled his slumber, would not credit the first report of his astonished officers; but investigation showed him that the "old fox" was gone, and he would not be bagged that morning--nor on any other morning, either! But where had he gone? For a time the perplexed and chagrined commander could not ascertain.