Afterwards taking the field with the army in the Jerseys, the regiment was engaged in the operations designed to bring the enemy to a general engagement, but the Americans kept close in their fortified lines in the mountains; and an expedition against the populous and wealthy city of Philadelphia was resolved upon. The FIFTEENTH, commanded by Lieut.-Colonel John Bird, were employed in this enterprise, and were formed in brigade with the seventeenth, forty-second, and forty-fourth regiments, under Major-General (afterwards Earl) Grey. Embarking from Sandy Hook, the army sailed to the Chesapeake, and proceeding up Elk River, landed on the northern shore on the 25th of August. The American army took up a position at _Brandywine_ to oppose the advance, and on the 11th of September the royal forces moved forward to engage their opponents. The FIFTEENTH formed part of the column under Major-General the Earl Cornwallis, which made a circuit of some miles to turn the right and gain the rear of the American army. The action proved decisive; the enemy was driven from his position, and forced to make a precipitate retreat. The battalion companies of the regiment did not sustain any loss on this occasion; but the flank companies, being formed in grenadier and light infantry battalions, had Lieutenant Faulkener killed; Captain Cathcart, Captain Douglas, and Lieutenant Leigh wounded; also several men killed and wounded. After this victory, the army continued its advance; Philadelphia was taken possession of, and the British troops took up a position at Germantown, the FIFTEENTH being posted on the left of the village. Making a forced march during the night of the 3rd of October, the American army appeared suddenly in front of _Germantown_ before daylight on the following morning, and attacked the British outposts, thinking to surprise the troops in an unprepared state. The first assault was opposed by the second battalion of light infantry, and the fortieth regiment, under Lieut.-Colonel Musgrave, posted at the head of the village; these corps were forced to fall back, and Lieut.-Colonel Musgrave threw himself, with six companies of the fortieth, into a large store-house, where he was attacked by an American brigade, aided by four pieces of cannon. During the contest, while the soldiers of the fortieth were defending their post manfully, Major-General Grey brought forward the FIFTEENTH, and two other corps; and making a determined attack on the American regiments, drove them back with great slaughter. The enemy was also repulsed at every part of the field, and forced to make a precipitate retreat.