LONDON.- Sotheby’s Old Master and British Paintings Evening Sale will include a portrait of Lord Lansdowne, acknowledged by the first American President George Washington as someone to whom the new United States of America owed a great deal. This painting by Jean Laurent Mosnier, named Portrait of William Petty, 2nd Earl of Shelburne, 1st Marquess of Landsdowne (1737-1805), Seated Three Quarter-Length In General’s Uniform With Garter Ribbon, The Lesser George Tied To His Sash, is estimated at £200,000-300,000. Commenting on this painting, Emmeline Hallmark, Head of Sotheby’s London British Paintings Department, said: Lord Lansdowne was a fantastically enlightened man as well as a patron of the arts. A great mind and political figure of his day, his contribution to British-American relations was extraordinary. This portrait, which