In the 23 years since his first hit, "Cry, Cry, Cry", Johnny Cash, the Man in Black, has become perhaps the most public figure in country music. His name and his remarkably distinctive voice (considering its extremely limited range) conjure up immediate images of trains, prisons, life on the land, and a certain rugged individualism and Christian faith.

Alas, the show Cash brought to a sold-out Wolf Trap Saturday night contained most of the elements but practically none of the passion that have made him such a recognizable figure. It's as if he is still doing a television variety show: Too much time is allocated to insignificant numbers performed by musically dull members of his and wife June Carter's family.

Cash's duets with Carter were somewhat stiff. Her control and range seem to have diminished in recent years, though the rough edges were less bothersome on the Carter Family clasics. Cash's best moments came in a railroad song medley, with a film of various trains and train wrecks playing behind him. This showed just a little of the imagination that was missing from much of the evening's entertainment. There's too much rich material in Cash's past that deserves a hearing.

Ironically, the musical highlight of the evening was an instrumental reading by Cash's pianist of Floyd Cramer's "Last Date." Its grace and symmetry were matched by the honest sentimentality of its performance. One would have appreciated a similar, consistent effort an acknowledged master and major figure in country music history.