To conceal as long as possible the real object of this movement, the march of the army was continued until the thirty-first, in such a direction as to keep up fears for New York; and a considerable degree of address was used to countenance the opinion that the real design was against that place.  The letters which had been intercepted by Sir Henry Clinton favoured this deception; and so strong was the impression they made that, even after it became necessary for the combined army to leave the route leading down the Hudson, he is stated to have retained his fears for New York, and not to have suspected the real object of his adversary until he had approached the Delaware;[83] and it had become too late to obstruct the progress of the allied army towards Virginia.  He then resolved to make every exertion in his power to relieve Lord Cornwallis, and in the mean time to act offensively in the north.  An expedition was planned against New London, in Connecticut, and a strong detachment, under the command of General Arnold, was embarked on board a fleet of transports, which landed early in the morning of the 6th of September on both sides the harbour, about three miles from the town.

[Footnote 83:  The first indication given by Sir Henry Clinton of suspecting the southern expedition, is in his letter to Lord Cornwallis of the 2nd of September, in which he says, “By intelligence I have this day received, it would seem that Washington is moving southward.”]

New London is a seaport town on the west side of the Thames.  A fort called fort Trumbull, and a redoubt had been constructed just below it, on the same side of the river; and opposite to it, on Groton hill, was fort Griswold, a strong square fortification, but not fully manned.  General Arnold, who commanded in person the troops that landed on the western side of the harbour, advanced immediately against the posts on that side.  These being untenable, were evacuated on his approach; and he took possession of them with inconsiderable loss.  To prevent the escape of the vessels up the river, Lieutenant Colonel Eyre, who commanded the division which landed on the Groton side of the harbour, had been ordered to storm fort Griswold, which had been represented to Arnold as too incomplete to make any serious resistance.  But the place being of some strength, and the approach to it difficult, Colonel Ledyard, who commanded it with a garrison of one hundred and sixty men, determined to defend it.  On his refusing to surrender, the British assaulted it on three sides, and overcoming the difficulties opposed to them, made a lodgement on the ditch and fraized work, and entered the embrasures with charged bayonets.  Further resistance being hopeless, the action ceased on the part of the Americans, and Colonel Ledyard delivered his sword to the commanding officer of the assailants.  Irritated by the obstinacy of the defence, and the loss sustained in the assault, the British officer on whom the command had devolved,