A large Federal force advanced to Malvern Hill, and was drawn up there in line of battle, with every indication on the part of General McClellan of an intention to advance anew upon Richmond.

Lee promptly went to meet him, and a slight engagement ensued on Curl's Neck.

But, on the next morning, the Federal army had disappeared, and the whole movement was seen to have been a feint.
This state of indecision continued until nearly the middle of August.
An incident then occurred which clearly indicated the enemy's intentions.

General Burnside was known to have reached Hampton Roads from the Southern coast with a considerable force, and the direction which his flotilla now took would show the design of the Federal authorities.

If a new advance was intended from the James, the flotilla would ascend that river; if General Pope's army was looked to for the real movement, General Burnside would go in that direction.
The secret was discovered by the afterward celebrated Colonel John S.
Mosby, then a private, and just returned, by way of Fortress Monroe, from prison in Washington.