ing the last decade, art sales have made headlines-the $5.54 million purchase of Velazquez's Juan de Pareja by the Met- ropolitan Museum of Art, for example. In 1970, it was the high- est price ever paid for a painting. Last June's $13.4 million sale of masterpieces from the Robert von Hirsch collection of Gothic, Romanesque, and Renaissance art was described as the largest one-day receipt in the history of art auctions. But in the late 1920s and '30s,a series of art sales of still unequalled magni-...