Artillery supported the 13th Regiment’s charge against Fort Sanders at Knoxville in the ice and snow of winter, 1863. The big guns were spread out so far around the southern curve of the battlefield that their commander had to use signal flags to tell them when to cease firing.

The commander, Gen. Edward Porter Alexander, had learned the wig wag signal flag system as a U.S. Army officer before the war under Albert J. Myer, an army surgeon.

“I was one of the very few, if not the only Southern officer who knew Myer’s system of signals,” Alexander wrote in his memoir Fighting For The Confederacy.

“Both the Union and the Confederacy,” writes Trevor at Fold3, an online archive of military records, “developed an army Signal Corps during the Civil War. The job of the Signal Corps in both the North and South was to quickly and accurately relay information and orders between the commanders of different units within the two forces (which was especially crucial during battles). The main way they did this was through the use of a flag system called wig-wag…”

At Knoxville Alexander used them for signaling his widely-spread artillery when to cease firing. The ceasing had been planned in advance by Gen. Longstreet, whose troops had dubbed him the Bull of The Woods a few months before after the Battle of Chickamauga.

“The Bull of The Woods has decided there will be no long artillery bombardment of the fort before the attack as previously planned,” my fictional Private Bird Clark of the Minutemen of Attala says in my historical novel Knoxville 1863. “Our infantry are to make the assault a big surprise attack, all by our own selves.”

And so it went in the historical record, with Alexander wig-wagging his batteries to cease fire as the attack got underway. Not long into the attack, however, Alexander had a change of heart and threw his red and white wig wag flags into motion again. He signaled his batteries to recommence the fire support, apparently on his own initiative, despite his superior’s orders to the contrary.