Jacob Lawrence was only 24 years old when Edith Halpert’s Downtown Gallery, on East 51st Street, exhibited his “Migration Series” in 1941. The series was first shown by itself for one week in November to coincide with the reproduction of several of its paintings in a spread in Fortune magazine, which had been seeking a way to dramatize the plight of African-Americans’ northward migration in the interwar years. Various forces — not least an invasion by crop-devastating boll weevils, depicted in one of Lawrence’s memorable images — had been destroying the agrarian life Southern blacks had clung to ever since emancipation. In December of that year, Lawrence’s paintings of the “Great Migration” again appeared in Halpert’s gallery, as part of a groundbreaking exhibition, assembled by Halpert with the writer Alain Locke, surveying the achievements of African-American artists.