[Sidenote: May 1.]

Not long after this incursion into Jersey, an enterprise was
undertaken against General Lacy, who, with a small number of
Pennsylvania militia, seldom amounting to six hundred, and sometimes
not exceeding fifty, watched the roads leading to Philadelphia on the
north side of the Schuylkill, and was generally posted within twenty
miles of that town.

[Sidenote: General Lacy surprised.]

This expedition was entrusted to Colonel Abercrombie and Major Simcoe,
who avoided all the posts Lacy had established for his security, and
threw a body of troops into his rear before he discovered their
approach. After a short resistance, he escaped with the loss of a few
men killed, and all his baggage. His corps were entirely dispersed,
and he was soon afterwards relieved by General Potter.

To maintain the command of the water as far as was practicable,
congress had ordered impediments to be sunk in many of the rivers of
common use, so as to obstruct the passage up them, and had
constructed frigates, and other smaller vessels, to be employed above
those impediments or elsewhere, as the occasion might require. Several
of them had been commenced above Philadelphia, but were not completed
when the British obtained the command of the river. General Washington
then became apprehensive for their safety, and repeatedly expressed
his desire that they should be sunk in such a manner as to be weighed
with difficulty, should any attempt be made to raise them. The
persons, however, who were entrusted by congress with this business,
supposed it would be equally secure to put plugs in their bottoms,