The Americans now assumed the offensive. Count d'Estaing was approaching the coast with a powerful French fleet. Should he be able to defeat Lord Howe and get control of the Delaware river, the British army in Philadelphia would be in danger of capture. Accordingly on the 18th of June that city was evacuated by Sir Henry Clinton and occupied by Washington. As there were not enough transports to take the British army around to New York by sea, it was necessary to take the more hazardous course of marching across New Jersey. Washington pursued the enemy closely, with the view of forcing him to battle in an unfavourable situation and dealing him a fatal blow. There was some hope of effecting this, as the two armies were now about equal in size--15,000 in each--and the Americans were in excellent training. The enemy were overtaken at Monmouth Court House on the morning of June 28, but the attack was unfortunately entrusted to Lee, who disobeyed orders and made an unnecessary and shameful retreat. Washington arrived on the scene in time to turn defeat into victory. The British were driven from the field, but Lee's misconduct had broken the force of the blow which Washington had aimed at them. Lee was tried by court-martial and at first suspended from command, then expelled from the army. It was the end of his public career. He died in October, 1782. After the battle of Monmouth the British continued their march to New York, and Washington moved his army to White Plains. Count d'Estaing arrived at Sandy Hook in July with a much larger fleet than the British had in the harbour, and a land force of 4000 men. It now seemed as if Clinton's army might be cooped up and compelled to surrender, but on examination it appeared that the largest French ships drew too much water to venture to cross the bar. All hope of capturing New York was accordingly for the present abandoned. [Siege of Newport, Aug. 1778.] The enemy, however, had another considerable force near at hand, besides Clinton's. Since December, 1776, they had occupied the island which gives its name to the state of Rhode Island. Its position was safe and convenient. It enabled them, if they should see fit, to threaten Boston on the one hand and the coast of Connecticut on the other, and thus to make diversions in aid of Sir Henry Clinton. The force on Rhode Island had been increased to 6000 men, under command of Sir Robert Pigott. The Americans believed that the capture of so large a force, could it be effected, would so discourage the British as to bring the war to an end; and in this belief they were very likely right. The French fleet accordingly proceeded to Newport; to the 4000 French infantry Washington added 1500 of the best of his Continentals; levies of New England yeomanry raised the total strength to 13,000; and the general command of the American troops was given to Sullivan.