An example of real slackness was being given by Howe at New York. He should with the aid of the fleet have made a prompt effort to prevent Washington from retreating from Manhattan island, and to cut off his communications with Connecticut whence he was drawing supplies. Even before occupying New York he might have conveyed his army by water to a point from which White Plains, where the land begins to broaden out rapidly, might have been reached with ease. He wasted four weeks of precious time at New York, and did not embark his troops till October 12. Washington left his narrow position on Haarlem heights, gained White Plains before him, and fortified his camp. Howe attacked him on the 28th with the object of outflanking him. Although part of his army by a frontal attack drove the American right from a strong position, this success was fruitless as well as costly. The insurgents' centre was weak, and if he had attacked it in force he might have crushed them completely. He made no further attempt in that direction, and Washington retreated to a good position behind Croton river. Howe returned to New York. There, however, he dealt the Americans a serious blow. Fort Washington, on Manhattan island, and Fort Lee, opposite to it on the Jersey shore, were intended to bar the Hudson and so secure communications with the country to the west of it. Congress, which often interfered in military matters, ordered that Fort Washington should be held, though in fact the forts did not prevent our ships from passing up the river. On November 16 a well-planned attack was made upon the fort; it was forced to surrender, and 2,858 prisoners, forty-three cannon, and a large quantity of small arms were taken by the British.