Civil War expert Gary Scott didn't mind the thick dust and pigeon droppings that he brushed aside to get into file boxes stashed in an attic around 1868 and then forgotten. Inside he found detailed records of the federal government's attempt to settle military records of Union soldiers who were missing in action.

The documents were from the office of Clara Barton, the famous nurse of the Civil War, who was hired by the government to close out files of men who were not accounted for at war's end. She worked in a third-floor office at 437 Seventh St. NW, a building now slated for demolition.

Scott, the National Park Service's chief historian for the Washington region, was delighted to find more than 10 boxes of documents, files and posters dating from 1865 to 1868. However, he was thrilled with an ornate metal sign that read: "Missing Soldiers Office, 3rd Story, Room 9, Miss. Clara Barton."

"This is our most significant find," he said, using white gloves to handle the sign. "It tells the story of her work after the Civil War, in the period of time before she founded the Red Cross. We don't know much about this part of her life."

Barton was 40 when she went to war as a nurse, managing to be at most of the major battles with her medical supplies and prayers ready for the thousands of wounded soldiers. Called the "Angel of the Battlefield," she was so revered by the soldiers she helped that many would later name their daughters Clara, according to Professor Ed Smith, of American University, a Civil War authority known for his work on the involvement of African Americans in the war.

"She never married," Smith said. "All those Claras named for her were a progeny as real as if they came from her womb."

Smith said Barton was fond of many of the regiments but "adopted" the black 54th Regiment of Massachusetts, accompanying it into battle at Fort Wagner and caring for the few who survived.

Her admiration for soldiers is evident in posters she sent out from her office after the war, seeking information on hundreds who had not returned home. At the top of the long list, she addressed a brief letter to "Soldiers and Friends of Soldiers" that read, "These are names of persons whose friends have written to me for information and about whom, up to this date, I have learned nothing definite."

The letter continues, "If anyone sees his own name or that of a comrade known to be living, he will please inform me." The return address was simply "Clara Barton, Washington D.C."

Scott said Barton found out what happened to 22,000 soldiers before closing her office in 1868.

On one of the lists sent to post offices are the names of three men from the District. They are David R. Lane, Company D, 1st Cavalry; Albion Ridlow, Company H, 1st Cavalry; and Guilford Williams, Company E, 2nd Infantry.

Among other artifacts rescued from the dirty attic were a frock coat, an embroidered slipper and a felt hat.

Scott said he was led to the extraordinary find by a man who was assisting a contractor hired to estimate the cost of demolition of the three-story brick building in a commercial area that dates to the founding of the city. Scott, who would not reveal the man's name, said the worker realized what he had found and wanted it to be put into the Park Service's hands for safekeeping.

"He is a real hero to me," Scott said. "That building might have come down with all these things inside." CAPTION: National Park Service historian Gary Scott with a book he is using for reference in studying the artifacts. CAPTION: A sign in the Seventh Street NW building directed visitors to Red Cross founder Clara Barton, who searched for missing Civil War soldiers from 1865 to 1868.