Dedication Ceremony for the New State Dining Room Mantel. Alice Roosevelt Longworth delivers remarks at the dedication of a newly-installed mantel in the State Dining Room; the mantel was a gift of both the architecture firm Steinmann, Cain White and the Marble Industry Board of New York. Left to right: stone cutters, Guido Ratti and Alex Salvioli; President John F. Kennedy; Mrs. Longworth; honorary chairman of the Fine Arts Committee, First Lady Jacqueline Kennedy; John J. Powers, of the Marble Industry Board of New York; Edwin B. Olsen and Walker O. Cain, of the architecture firm Steinmann, Cain White; Malcolm Cohen, of the Marble Industry Board of New York. White House, Washington, D.C.