Dabney explained that he and his wife had worked out a signaling system based on the laundry that she hung out to dry at her mistress's house, which was observable from Hooker's headquarters. As the wife observed Confederate troop movements, she would hang the laundry in a particular sequence to signal Dabney of the activity. For example, a white shirt represented Gen. A. P. Hill, a pair of pants hung upside down represented the direction west, and so forth. This system produced useful intelligence on Confederate movements until Hooker moved his headquarters.