During the American Civil War , the Union Army quickly image out how to spiel Confederates ’ own bias against them . They found that many Confederate troops would speak openly about maneuver and troop movements or leave maps and orders out in plain horizon in front of black slave and servants . So low were the Southerner ’ judgement of African Americans , they could n’t suppose them doing anything utilitarian with the information they heard or saw . Reports from runaway slaves and free African Americans from the North that joined the Army as scouts and spies became so priceless to the Union that they were localise in a exceptional class by intelligence officers : black expeditiousness .
The most celebrated of the spies was Harriet Tubman . But two of the more creative provider of black dispatches were a Isle of Man named Dabney and his wife , who worked with Union troops around Fredericksburg , Virginia in 1863 . The runaway slaves had crossed into Union territory sooner that year , and Dabney found usage in General Joseph Hooker ’s encampment as a cook . His knowledge of the area also made him a large asset , and he was presently advise military personnel venturing into foe dominion on route and terrain .
After a few workweek in the summer camp , Dabney ’s wife pass on for Confederate territory to take a job as a laundress and personal servant to a southerly cleaning woman . Not long after she leave , Dabney start bringing reports about Confederate movements to Hooker . His information proved exact : he always know which units were move , where they were going , how long they ’d been on the march , and what numbers they had . He was spry , too , and Hooker found that Dabney ’s selective information usually reached him just hours after it was discussed by rebel commander on the other side of the lines .
utile as they were , Dabney ’s reports were vex . No one ever envision him provide the bivouac , abandon his responsibility , or even talk to yield scouts . Some officers decided to figure out where Dabney was have his news and questioned him at length . Dabney in conclusion gave in and led them to an elevated compass point in the camp . From that advantage point in time , they had a clear sentiment of Fredericksburg and much of the beleaguer orbit .
Dabney pointed to a sign of the zodiac on the outskirts of the township , along the river bank . Out in its yard , there was a clothesline where clothing and sheets were hung out to dry . He and his wife , Dabney explained , had turn out their own signalize system using the washing that she hung out to dry out for her employer . Whenever she saw troops moving through the area or heard soldier discussing plans in town , she would hie to the clothesline and fall item in particular ways and chronological succession — a red shirt to represent Stonewall Jackson , an upside - down span of bloomers to signify westward movement — to beam Dabney a coded message .
Until Hooker moved his ingroup , the cook , his married woman and the Confederates ’ marked-up laundry provided him with some of the best intelligence of the military campaign .
