"In the panic after Pearl Harbor, German planes were reported nearing the coast; the Boston Museum rushed its treasures out of sight. The National Gallery in Washington very intelligently secured the vast empty Vanderbilt chateau of Biltmore in the North Carolina mountains, to shelter the chief masterpieces of the Mellon Collection. The Metropolitan first thought, on the example of the National Gallery in London, of an abandoned mine or quarry, and was on the point of taking one up the Hudson. Fortunately, the prolonged drought during which they inspected it came to an end, and water began to seep in just before they were to occupy it. Various empty country houses were offered them. Soon they announced they had taken a country place, "a hundred miles inland." It was Whitemarsh Hall. Priorities on materials were somehow secured; steel racks for paintings were put up in the salon, steel shutters at the windows. Packing cases were piled in the billiard and other rooms.
Other institutions sent their treasures there also, so that if a single bomb had landed it would have destroyed them all. The hysterical rush to put things in Whitemarsh Hall inspired Hardinge Scholle of the Museum of the City of New York, who had at first participated in the movement, to call the house a 'monument hystérique'."
George and Mary Roberts, Triumph on Fairmount: Fiske Kimball and the Philadelphia Museum of Art (Philadelphia: J.B. Lippincott Company, 1959).