Archibald J. Motley Jr., Blues, 1929. Oil on canvas Imagine a dance hall in 1929. It’s Saturday night and dancers fill Ruggles Hall in Roxbury, bouncing to the beat of a string bass and drums as a trumpeter belts out Ain’t Misbehavin’. Now travel a mile north to Symphony Hall, where another trumpeter stands in front of an orchestra and sounds the opening notes of the Haydn Trumpet Concerto in Eb. At the exact same moment the first valve on each trumpet sticks, and their tone is suddenly...