The Battle of Chantilly, or Ox Hill, was fought in a driving rain storm on September 1, 1862. It was the final engagement of the Second Manassas Campaign.
After his victory at Second Manassas, Robert E. Lee sent Stonewall Jackson on another flanking movement in an attempt to get between John Pope's army at Centreville and Washington. Pope successfully blocked this movement primarily with Isaac Stevens's division of the Ninth Corps and then Phil Kearny's division of the Third Corps.
Late in fhe day, Branch's brigade of A. P. Hill's division was engaged against Birney's brigade of Kearny's division. Branch told Hill that he wasn't sure his brigade could hold much longer since the rain had soaked their ammunition. Hill told Branch to hold his position with the bayonet if necessary. However, Hill sent a message to Stonewall Jackson: "My compliments to General Jackson and my request to be permitted to take my command out of the line because all my ammunition is wet.”
The messenger found Jackson and then relayed his reply to Hill: “My compliments and tell him the enemy’s ammunition is equally wet as his!”