Grace notes: Art as a reverie of gentle sounds

French artist and composer Céleste Boursier-Mougenot's "Clinamen," at the Park Avenue Armory in New York City, is a mesmerizing installation in which porcelain bowls floating in giant basins of water collide, producing chiming sounds that reverberate in the 55,000-square-foot hall, to foster a state of grace. Tracy Smith reports.