Lovers of sculpture who prefer clay to other materials have much to celebrate this month in Chicago, with a not-to-be-missed pair of shows at the Smart Museum of Art and the Art Institute, respectively dedicated to Ruth Duckworth and contemporary Japanese women ceramicists. Those who prefer marble and bronze, and especially those torn between all these substances, need not dismay. Also ongoing at the AIC is an exhibition of clay sculptures made by the 18th century Italian master Antonio Canova as preparatory sketches for his famously lifelike marble figures of Pope Clement XIV, Napoleon’s mother and a variety of mythological...