FAME IS FICKLE as firelight. The National Portrait Gallery is showing Mathew Brady photographs of world-famous people you never heard of, including Francis Chanfrau, Pauline Cushing and the beloved Dan Rice.

It's another helping of prints from the fabulous Frederick Hill Meserve Collection of photographs of Abraham Lincoln and his contemporaries, purchased by the gallery in 1981. These 60 new albumen prints, which also include a lot of people we have heard of, were made from the original glass plates rescued by Meserve at the turn of the century.

Poor Brady, who bankrupted himself maintaining teams of photographers in the field during the Civil War, had to give up his treasury of civilian and military photographs because of debts and storage costs. He died penniless. Much of his collection, probably the world's richest trove of historical images, might have been lost forever if not bought up by amateur historian Meserve.

Included in this selection are wallet-sized "cartes de visit" of Lincoln and the men who served -- and/or vexed -- him through our great national trial, plus such semi-immortal personages as P. T. Barnum and an 18-year-old fop named Edward, Prince of Wales, later the dissolute King Edward VII.

But visitors may tend to linger over the portraits of such now-obscure celebrities as Chanfrau (1824-1884), one of the 19th century's great comic actors; Cushman (1833-1893), a comely Northern spy whom Union troops rescued from the shadow of a Southern gallows; and Rice (1823-1900), America's first great circus clown, who drew down $1,000 a week in a time when a man who made that much in a year was counted rich.

LINCOLN AND HIS CONTEMPORARIES: Mathew Brady Photographs From the Frederick Hill Meserve Collection -- Through Feb. 17 at the National Portrait Gallery. Open daily 10 to 5:30. Metro: Gallery Place.