Their joy at their escape when (as Major Humphreys, who was with them, said) they had been given up for lost by their friends, was tempered next day by the death of Colonel Knowlton, who had been sent out with his rangers to reconnoiter the enemy. In the ensuing engagement, known as the Battle of Harlem Heights, the gallant Knowlton was killed, besides about one hundred and seventy of his men. Knowlton, who had taken a prominent part in the battle of Bunker Hill, was an old friend and comrade of Putnam in the Indian wars, as well as at Havana, and the latter felt his loss most keenly. There was no time for vain regrets, since the enemy were pushing after the Americans, giving them no pause for a while. When at last there was a cessation in their endeavors at direct assault, Washington was more uneasy than before, and did not rest until he had discovered what it meant. In short, General Howe was about trying the second in his remarkable series of flanking movements, by which he hoped to get in the rear of the Americans, and, with his overwhelming force, "bottle them up" and compel a general engagement. But, with a force far inferior to the British, Washington not only succeeded in avoiding a pitched battle (for which he was wholly unprepared), but finally extricated his army from the net which his enemy had spread on two sides and was now attempting to sweep around to cut off his retreat. Sending several war-vessels up the North River, or Hudson (which had no trouble in breaking through the barrier stretched across it), General Howe embarked the main body of his troops in flatboats for Westchester, landing at a point about nine miles above the Heights of Harlem. The enemy's object was then apparent, and Washington set about defeating it by one of the most complicated and ingenious military movements on record. Leaving General Greene in command of Fort Washington, on the Hudson, not far from Kingsbridge and the Heights, Washington hastened northward toward White Plains, seizing upon every naturally strong position by the way, and establishing a chain of entrenchments on the hill-crests that commanded all the roads leading from the North River to the Sound. The last week in October the opposing forces came in collision at Chatterton Hill, where was fought the so-called Battle of White Plains, at which, wrote Rufus Putnam, who had planned the defensive works, "the wall and stone fence behind which our troops were posted proved as fatal to the British as the rail-fence with grass hung on it did at Charlestown, June 17, 1775."