It may be supposed we did not linger

From 1776 by David McCulough. Page 189. 

At the ferry landing all this time troops and supplies and artillery were being loaded aboard one boat after another as quickly as humanly possible and sent on their way. Everyone worked furiously. A Connecticut soldier manning one of the boats would remember making eleven crossings in the course of the night.

But the exodus was not moving fast enough. Some of the heavy cannon, mired in mud, were impossible to move and had to be left behind. Time was running out. Though nearly morning, a large part of the army still waited to embark, and without the curtain of night to conceal them, their escape was doomed.

Incredibly, yet again, circumstances—fate, luck, Providence, the hand of God, as would be said so often—intervened.

Just at daybreak a heavy fog settled in over the whole of Brooklyn, concealing everything no less than had the night. It was a fog so thick, remembered a soldier, that one “could scarcely discern a man at six yards distance.” Even with the sun up, the fog remained as dense as ever, while over on the New York side of the river there was no fog at all.

At long last Mifflin and the rear guard and the troops at Fort Stirling were summoned. “It may be supposed we did not linger,” wrote Alexander Graydon.

Major Tallmadge, who with his regiment was among the last to depart on the boats, would write later that he thought he saw Washington on the ferry stairs staying to the very end.

Graydon estimated that it was seven in the morning, perhaps a little later, when he and his men landed in New York. “And in less than an hour after, the fog having dispersed, the enemy was visible on the shore we had left [behind].”

In a single night, 9,000 troops had escaped across the river. Not a life was lost. The only men captured were three who had hung back to plunder.