Art: Britain's Liveliest Museum

A familiar profile along the Thames-side skyline in London is the sooty statue of Britannia, bearing a trident, atop the Victorian baroque pile that is the Tate Gallery. Britannia grasps her trident in what heraldry says is the wrong (that is, right) hand. In the past, this maladroitness has seemed symbolic of the Tate.

Sugar Merchant Henry Tate had the devil's own time getting the nation to accept his costly gift in 1890. A cruel tradition makes the Tate turn over any painting that can be defined as an old master to the National Gallery. For years, the public virtually ignored the...