General Wayne lay in the woods near the entrance of the road from Darby into that leading to Lancaster, about three miles in the rear of the left wing of the British troops encamped at Trydruffin, where he believed himself to be perfectly secure. But the country was so extensively disaffected that Howe received accurate accounts of his position and of his force. Major-General Gray was detached to surprise him, and effectually accomplished his purpose. About 11 in the night of the 20th his pickets, driven in with charged bayonets, gave the first intimation of Gray's approach. Wayne instantly formed his division, and, while his right sustained a fierce assault, directed a retreat by the left, under cover of a few regiments, who, for a short time, withstood the violence of shock. In his letter to Washington, he says that they gave the assailants some well-directed fires, which must have done considerable execution, and that, after retreating from the ground on which the engagement commenced, they formed again, at a small distance from the scene of action, but that both parties drew off without renewing the conflict. He states his loss at about 150 killed and wounded. The British accounts admit, on their part, a loss of only 7.
When the attack commenced, General Smallwood, who was on his march to join Wayne, a circumstance entirely unexpected by General Gray, was within less than a mile of him, and, had he commanded regulars, might have given a very different turn to the night. But his militia thought only of their own safety, and, having fallen in with a party returning from the pursuit of Wayne, fled in confusion, with the loss of only one man.
Some severe animadversions on this unfortunate affair having been made in the army, General Wayne demanded a court-martial, which, after investigating his conduct, was unanimously of opinion, "that he had done everything to be expected from an active, brave, and vigilant officer," and acquitted him with honor.
Having secured his rear, by compelling Wayne to take a greater distance, Howe marched along the valley road to the Schuylkill and encamped on the bank of that river, from the Fatland ford up to French creek, along the front of the American army. To secure his right from being turned, Washington again changed his position and encamped with his left near, but above, the British right.
Howe now relinquished his plan of bringing Washington to another battle, and thinking it advisable, perhaps, to transfer the seat of war to the neighborhood of his ships, determined to cross the Schuylkill and take possession of Philadelphia. In the afternoon he ordered one detachment to cross at Fatland ford, which was on his right, and another to cross at Gordon's ford, on his left, and to take possession of the heights commanding them. These orders were executed without much difficulty, and the American troops placed to defend these fords were easily dispersed.
This service being effected, the whole army marched by its right, about midnight, and crossing at Fatland without opposition, proceeded a considerable distance toward Philadelphia, and encamped with its left near Sweed's ford and its right on the Manatawny road, having Stony Run in its course.
It was now apparent that only immediate victory could save Philadelphia from the grasp of the British general whose situation gave him the option of either taking possession of that place or endeavoring to bring on another engagement. If, therefore, a battle must certainly be risked to save the capital it would be necessary to attack the enemy.
Public opinion, which a military chief finds too much difficulty in resisting, and the opinion of Congress, required a battle; but, on a temperate consideration of circumstances, Washington came to the wise decision of avoiding one for the present.
His reasons for this decision were conclusive. Wayne and Smallwood had not yet joined the army. The Continental troops ordered from Peekskill, who had been detained for a time by an incursion from New York, were approaching, and a reinforcement of Jersey militia, under General Dickenson, was also expected.
To these powerful motives against risking an engagement, other considerations of great weight were added, founded on the condition of his soldiers. An army, maneuvering in an open country, in the face of a very superior enemy, is unavoidably exposed to excessive fatigue and extreme hardship. The effect of these hardships was much increased by the privations under which the American troops suffered. While in almost continual motion, wading deep rivers, and encountering every vicissitude of the seasons, they were without tents, newly without shoes, or winter clothes, and often without food.