"There is always something new out of Africa," Pliny the Elder observed in the First Century A.D.

Two thousand years later, Smithsonian's Anacostia Neighborhood Museum agrees with the Roman scholar. "Out of Africa," the museum's current exhibit, is a sight-and-sound demonstration of the Pliny proposition.

"This is the first time we have gone back to the roots in Africa. A lot of youngsters come here and say: 'We know we're from Africa but we don't know what that means,'" Carolyn Margolis, exhibit researcher, points out.

"Out of Africa" tries to show, at least by sample, what it means to have roots in Africa and to share its history.

It is an exhibit to hear as well as to see. There is the sound of tribal music -- some taped live in Africa -- on gourd kettledrums, log gongs, basket rattles, panpipes, stone whistles, and thumb pianos. There are authentic headdresses, masks, medical instruments and door panels, and Ashanti gold-weights that speak of plants, wildlife and customs.

Pick up an exhibit telephone and hear a reading drawn from the letters of a 10-year-old passenger on a slave ship. And there is a taped reading of Henry Highland Garnett's fiery speech, "Let Your Motto Be Resistance."

Yesterday, students from the Brookfield School in Montgomery County and the Andrews Air Force Base elementary school were clapping and chanting as they joined the chorus for an Ibo tribal song. Later, with slides of the musicians on a big screen, they watched the dance of an African medicine man to the sound of drums, singing, and tinkling to the bells of his metal anklets.

Also watching was Stephen Robinson, a 13-year-old visitor from Pittsburgh. He was making a spring vacation visit to his grandmother, Ruth King, whose father, Elzie S. Hoffman, a pioneer black musician, lived in the Anacostia neighborhood of the museum.

Larry Erskine Thomas, the exhibit designer, lived 10 years in Ethiopia. He has made dramatic use of thatched roofs for display items and recreated a slave fort and deck of a slave ship.

"There is something exciting about seeing the real thing. This is the actual diary of a doctor who served on a slave ship in the 1950s and there is the account book of a slave trader," Margolis said.

And then there is a display on the heyday of Timbuktu, which existed as the undisputed seat of West African culture, learning, and commerce.

It took two years for the Anacostia museum staff to assemble and install the exhibit, which draws from the collections of the Museum of African Art, Howard University, and Smithsonian's Museum of Natural History.

The Anacostia Neighborhood Museum, on Ancostia's main street at 2405 Martin Luther King Jr. Ave. SE, is open from 10 a.m. to 6 p.m. weekdays and from 1 p.m. to 6 p.m. weekends. To accompany the show, which will continue throughout this year, the museum has arranged a series of demonstrations on pottery making, dance, musical instruments, hairplaiting and other subjects.Special tours and information on demonstrations is available by calling 381-6731.