Art Is Long, Cash Is Better

London police admitted last week they haven't a clue as to why thieves in the last six months have spirited away at least 20 bronze sculptures, each weighing half a ton or more.

On Jan. 10, at a university campus in Roehampton, a 2.2-m-tall sculpture weighing one-third of a ton by the British modernist Lynn Chadwick was hacked from its plinth. One of a trio of figures, The Watchers, it is valued at $1 million — far less than the $5.4 million price tag on Henry Moore's 2.5-ton Reclining Figure that in December was lifted, using a stolen...