The day after receiving intelligence of the evacuation of fort
Mifflin, General Washington deputed Generals De Kalb, and Knox, to
confer with General Varnum and the officers at fort Mercer on the
practicability of continuing to defend the obstructions in the
channel, to report thereon, and to state the force which would be
necessary for that purpose. Their report was in favour of continuing
the defence. A council of the navy officers had already been called by
the Commodore in pursuance of a request of the Commander-in-chief made
before the evacuation had taken place, who were unanimously of opinion
that it would be impracticable for the fleet, after the loss of the
island, to maintain its station, or to assist in preventing the
chevaux-de-frise from being weighed by the ships of the enemy.

General Howe had now completed a line of defence from the Schuylkill
to the Delaware; and a reinforcement from New York had arrived at
Chester. These two circumstances enabled him to form an army in the
Jerseys sufficient for the reduction of fort Mercer, without weakening
himself so much in Philadelphia as to put his lines in hazard. Still
deeming it of the utmost importance to open the navigation of the
Delaware completely, he detached Lord Cornwallis about one in the
morning of the 17th, with a strong body of troops to Chester. From
that place, his lordship crossed over to Billingsport, where he was
joined by the reinforcement from New York.

{November 17.}

General Washington received immediate intelligence of the march of
this detachment, which he communicated to General Varnum with orders
that fort Mercer should be defended to the last extremity. With a view
to military operations in that quarter, he ordered one division of the