On the night of Nov. 4, a heavy rumbling sound was heard in the direction of the British camp. It continued all through the night, and resembled the noise of wagons and artillery in motion. Day break disclosed the cause: the enemy was decamping. Long trains were seen moving over the hilly country towards Dobb's Ferry on the Hudson.
"A feint!" said General Lee, as soon as he discovered the situation.
"A retreat, more like," replied another officer. "The enemy sees little hope in attacking this stronghold."
"I can hardly believe that so large and well-disciplined an army is going to withdraw without giving battle," responded Washington. "No doubt an attack upon Fort Washington is the immediate purpose; and then, perhaps an invasion into the Jerseys."
There was much speculation among the officers as to the meaning of this manœuvre, and all of them were in more or less perplexity. Washington wrote immediately to Governor Livingston of New Jersey and hurried a messenger away with the letter:
"They have gone towards North River and King's Bridge. Some suppose they are going into winter quarters, and will sit down in New York without doing more than investing Fort Washington. I cannot subscribe wholly to this opinion myself. That they will invest Fort Washington is a matter of which there can be no doubt, and I think there is a strong probability that General Howe will detach a part of his force to make an incursion into the Jerseys, provided he is going to New York. He must attempt something on account of his reputation, for what has he done as yet with his great army?"
Satisfied that General Howe intended to capture Fort Washington, he advised its evacuation. He wrote to General Greene:
"If we cannot prevent vessels from passing up the river, and the enemy are possessed of all the surrounding country, what valuable purpose can it answer to hold a post from which the expected benefit cannot be had? I am, therefore, inclined to think that it will not be prudent to hazard the men and stores at Mount Washington; but as you are on the spot, I leave it to you to give such orders as to evacuating Mount Washington as you may judge best, and so far revoking the orders given to Colonel Morgan, to defend it to the last."