Ara Lee Settle, a high school student in Washington, probably never imagined that she would be a part of history, that her letter to the president would be read by other students more than a half century after she wrote it.

Settle attended old Armstrong High School, Washington's vocational training school for blacks in an era of segregated schools. Her letter, two carefully typed pages, was written in 1922 to President Harding, pleading with him to stop the lynchings of blacks.

How the White House answered Settle isn't recorded. Her letter was passed on to the Justice Department and eventually to the National Archives where it became part of the 1 1/4 million cubic feet of documents that form what has been called the nation's memory. It was there the letter was rediscovered a few years ago by Mary Alexander, an education specialist at the Archives, who was searching for documents--what historians call "primary sources"--for use in high school history classes.

Settle's letter is part of a collection of documents culled from the Archives and used in 1,500 schools across the country. Many of the documents are not from presidents or generals or the famous that usually populate history books, but from people like Ara Lee Settle who, for better or worse, got caught up in American history.

There are copies of letters from distressed farmers to President Roosevelt during the Depression, reports from local officials of the WPA and copies of posters used by the NAACP and the Ku Klux Klan during the '20s. Alexander, a former high school history teacher, calls it "history in the raw," an antidote to the perception that history "is found only in books that weigh a lot and are filled with names and dates to be memorized and forgotten."

So that the Archives could, in effect, go to high schools, members of its Education Division put together packets of documents and teacher's guides for five periods in American history: the Civil War, the Twenties, the Depression and the home front during World Wars I and II.

The documents collected -- about 50 for each era and including everything from letters to advertisements -- offer a more personal view of the past than most textbooks.

"Don't let your wife toil over the tub" urged a 1920 advertisement for washing machines with the promise that a new electric washer "will make her happy, keep her healthy and supply you with clean clothes."

A 1924 student survey about "moral problems in high school," reported that the "most regrettable practice of boys" was smoking, the answer of 38 percent of the students, followed by swearing, 19 percent.

Bad habits among the girls? Cosmetics, replied 17 percent of those surveyed, followed by flirting and petting, 14 percent, and profane language, 12 percent.

The results also noted "a goodly number of pupils regret the fact that the full meaning of life is not made clear to them by school."

The document kits are available ($30 each) from Social Issues Resources Series, Inc., P.O. Box 2507, Boca Raton, Fla. 33432, (800) 327-0513. The National Archives offers tours for students grades 5 through 12. For tour information, call 523-3184. For information about Archives' workshops, 523-3347.