To the left of the chancel is the Memorial Chapel, which houses the Brombaugh organ. Special services such as Monday Morning prayer, communion, and healing prayer are held in the Memorial Chapel, which seats 50.   The benefactors for whom the University is named, Washington Duke and his two sons, Benjamin N. Duke and James B. Duke, are entombed in the Memorial Chapel. The sarcophagi and the Memorial Chapel are gifts of the Duke Memorial Association. Organized in 1928 by James A. Thomas, the association received contributions from friends of the Dukes all over the world.   The windows of the Memorial Chapel are made of silvery tinted glass known as grisaille, and the windows of the crypt are composed of purple glass and lead grilles. A boss—an ornamental ceiling stone—with the Duke family coat of arms can be seen on the ceiling, and a plaque honoring philanthropist Doris Duke, daughter of James B. Duke, is located on one of the walls.