MASTERPIECES FOR SALE.

The English art dealer Joseph Duveen sold hundreds of Old Masters, for soaring prices, to American multimillionaires between the early years of the twentieth century and 1939, when he died, at the age of sixty-nine. Today, those works distinguish some of our greatest museums, notably the National Gallery of Art, in Washington, D.C., which opened in 1941 as a posthumous gift to the nation from the financier Andrew W. Mellon. Duveen's favorite architect, John Russell Pope, designed it, and Duveen clients--Mellon, Samuel H. Kress, the estate of Peter A. B. Widener--filled it with "Duveens," as canny visitors could tell at a glance. (The dealer's aggressive restorers gave old ...