BOONSBORO, Md. — Marshall Miller stood on the mountaintop vigorously waving a flag atop a hefty flag staff.
"One. Two. Two. One," his father, John Miller, called off behind him.
The elder Miller, historian for South Mountain State Battlefield, was dictating a code used by Union soldiers during the Civil War to send messages to far-off soldiers within view. Each combination of numbers represented a letter, and ultimately spelled out a message.
Marshall, 14, was assisting his father in a signal corps demonstration at Behind the Line of Battle: Communications and Overlooks, a living history encampment Saturday at Washington Monument State Park east of Boonsboro.
John Miller said the Washington Monument, which was erected by the citizens of Boonsboro in 1827 to honor George Washington, played an important role as a signal station for lines of communication throughout the Civil War.
Though it stands as a solid 34-foot structure today, the Washington Monument was dry-stacked when it originally was built, Miller said, and had started to collapse at the time of the Civil War more than 30 years later. Still, its location was ideal for signaling.
"It was good for Union or Confederate soldiers to come up here because there is such a wonderful view of the Cumberland Valley below," he said. "Union troops were up here during the Battle of Antietam as well as after the Battle of Gettysburg. And it played a very vital role in the Battle of Boonsboro."
Miller said flag signaling could be seen for up to 15 miles on a clear day.
Encampment organizers hoped to re-create from actual photos what camps really looked like when troops were stationed at the monument, Miller said. About 20 feet from the signaling demonstration was a makeshift fly — a form of shelter — covering a table and some period writing instruments.
"After a message had been sent up, they would have gone to the desk to translate," he said.
Benjamin Davids, 10, of Hagerstown, spoke at length with Miller about the aerial telegraphy known as "wig-wag" signaling. Benjamin's mother, Angela Davids, said he is studying the Civil War in his home schooling.
"I think this is a great way for him to see in person what he is studying. He gets to ask questions that are important to him," Angela Davids said. "He can read about it, but these details really help you visualize it and bring it to life."
Following the signaling demonstration, Benjamin tried on a re-enactor's 40-pound knapsack.
"This is awesome," he said. "I like costumes, the equipment. And you can touch it, too. It's very interactive. It adds to it."
Angel Nerona, 33, of Middletown, Md., went to visit the monument with her husband, Emerson, 49, and their sons, Joshua, 8, and Jacob, 7. The family was surprised to stumble upon the encampment, Nerona said.
"It's pretty cool. It brings everything back to life and makes you experience it," she said. "It's very emotional, very touching."
Nerona said she wished re-enactors and demonstrations were available when school students visit the site for field trips.
"Schools come here a lot. It's really different when you just walk up here, they are not here," she said. "When they are here, it makes it more worthwhile, more real."