On Nov. 13, 1862, the Confederate government advertised in the Charleston Daily Courier for 20 or 30 “able bodied Negro men” to work in the new nitre beds at Ashley Ferry, S.C. “The highest wages will be paid monthly,” the ad stated.

It was odious work. The nitre beds were large rectangles of rotted manure and straw, moistened weekly with urine, “dung water,” and liquid from privies, cesspools and drains, and turned over regularly, according to accounts at the time.

The process was designed to yield saltpeter, an ingredient of gunpowder, which the Confederate army desperately needed during the Civil War.

The wages for this repulsive task went, of course, not to those toiling in the beds, but to their owners.

The National Archives has made available online a trove of almost 6,000 Confederate government payroll records that account for money issued to hundreds of owners and others for the work of the enslaved.

The records provide a glimpse into the system in which a vast workforce — more than 29,000 people just in Virginia, according to historian Jaime Amanda Martinez — was compelled to labor on behalf of a war waged to preserve slavery.

Men, women and children were forced to work in places like a Petersburg, Va., lead factory that made bullets for the Confederate army.

A thousand “hands,” including laborers, brick layers and carpenters, rebuilt the old colonial installation, Fort Boykin, on the James River, for the Confederates.