"Lillian Gish is the history of the movies," says film studies professor Richard Brown of the legendary silent-film actress. "She invented the form."

Gish, 89, who starred in many of director D.W. Griffith's films, such as "Broken Blossoms," "True Heart Susie" and the landmark "Way Down East," will make a rare appearance Tuesday at the National Museum of Natural History's Baird Auditorium at 8 p.m. Her appearance will kick off "Lillian Gish, Ginger Rogers and Sally Field -- Three Generations of Great Hollywood Actresses," a series of evenings in which each of the leading ladies will discuss her career and experiences in the film industry.

"It's the actresses who have set the tone in terms of style," says Brown, who will interview the three stars. "The clothing that they wore, their makeup, the way they spoke . . . influenced the society."

Brown, a faculty member of the New School for Social Research and adjunct professor of film studies at Vassar College, says it was "a style of grace that Ginger Rogers set when she danced with Fred Astaire . . . an easy confidence in your life." Rogers, who made eight pictures in 1933, including "42nd Street" and "Gold Diggers of 1933," before teaming for the first time with Astaire in "Flying Down to Rio," will appear May 20.

"She represents to me what the term 'movie star' means right now," Brown says of Sally Field, who will conclude the series May 27. Field, a two-time Academy Award winner for her work in "Norma Rae" and "Places in the Heart," is "a role model for girls," according to Brown. "She's tough, she's strong, yet feminine."

Each session will include a retrospective of scenes from the stars' films as well as an opportunity for audience members to ask questions of the actresses. Tickets to the series, which is sponsored by the Smithsonian's Resident Associate Program, are available for individual sessions or for all three. For information call 357-3030.