Art: Invisible Art?

The 20th century has seen almost everything in the way of abstract sculptures, from huge sheets of hammered copper to tiny, tinkling aluminum mobiles. But Naum Gabo, a 62-year-old Russian, is the first sculptor to make his work almost invisible. Last week a syth Street gallery showed a few of his sculptures, mostly pieces of transparent plastic put together in sharp angles and looping curves to form abstractions as still and shiny—and about as warming—as winter sunlight.

Gabo's method is called "constructivism," and he has been at it for almost half a century....