In May 1778, while the British main army was in Philadelphia, and the American troops at Valley Forge, he was detached with about two thousand five hundred men under his command, to a position in advance of the continental camp and near the city, for the purpose of watching the motions of the enemy. The British endeavored to surround and surprise him: but he had timely notice of their plan, and retired in safety to the vicinity of WASHINGTON'S head-quarters. Had he been surprised in this situation, the result would probably proved fatal to our cause. For the continental troops under WASHINGTON were few in number and poorly clothed and armed. But the Commander in Chief, doubtless, was fully aware of the important and critical nature of the service, and entrusted it to one, in whose judgment as well as bravery he had perfect confidence. Soon after this, in the month of June, the British army left Philadelphia, to return to New-York. It consisted of as large a number of well disciplined troops, as they had in America at any one time; and though they chose not to make a direct attack upon WASHINGTON, they seem to have had no apprehensions of an attack from him. But he was resolved to avail of the occasion of their march through the State of New Jersey, to attack and annoy them. This he did on the memorable 28th of June, near Monmouth court-house; and had his judicious plan been faithfully executed, or his own personal activity and bravely been seconded by General LEE, who had the command of the troops more immediately engaged on that day, a great and decisive victory would in all probability have attended the daring enterprize. General LAFAYETTE had a distinguished command on that critical day. Lee, indeed, at first declined the command of the advanced corps, detached by WASHINGTON to harass the rear of the enemy while on their march; and it was given to the former: though; afterwards, when it was found, that the enemy was preparing for a general engagement, a reinforcement was ordered, and the whole placed under the command of General Lee. In this whole affair, General LAFAYETTE conducted with remarkable intelligence and bravery; and received the entire approbation of the Commander in Chief. In August of the same year (1778) when the enemy had a large force on Rhode Island, and were supposed to be meditating an attack on some place in the vicinity, Lafayette (with General Greene) offered his services as a volunteer. The expedition was not attended with success: the British troops then were more numerous than we could collect against them; and what were mustered were principally militia. The continental regiments were then all needed near New-York. But General Lafayette assisted in conducting the retreat of our men, with much skill and effect; and his behaviour on the occasion received the particular notice and approbation of Congress.