Keith Sonnier: Location one. (New York).

Keith Sonnier gained recognition in the early '70s for work that engaged the "new" medium of light. Along with Dan Flavin, Robert Irwin, and James Turrell, Sonnier experimented with neon and argon to create sculpture and installations that treated light and space as tactile materials rather than merely optical devices. The most ambitious of these works is the kilometer-long Lichtweg (Light path), 1992, a strip of colored neon that runs parallel to the moving sidewalk connecting the terminals at Munich's Franz-Joseph-Strauss Airport.

The installations in the recent exhibition "[O.sub.2] = [0.sub.3]: Fractured Oxygen = Ozone" were made in the '90s during a period in which Sonnier moved away from light and focused instead on energy, electricity, and more specifically, the work of a Serbian-American engineer and scientist named Nikola Tesla (1856-1943). Tesla's 700-plus patents include the Tesla coil transformer, the rotating magnetic field, the fluorescent light, the loudspeaker, alternating-current power transmission, wireless communication, and radio.

The seven large-scale sculptures installed in the dimly lit gallery are composed of transformers and copper rods, ceramic condensers, electrical cables, controllers, and a few electric lights. In most of the works, light is subordinate to energy. Ceiling Ladder and Wall Ladder, both 1997, feature high-voltage live currents that travel between metal conductors from transformers to ceramic condensers; in Wall Ladder, the ever changing, white-blue current crackles upward between six pairs of copper wires strung on the wall, a bit like a guitar. The current moves quickly, appearing at the juncture of wires and dissipating without a trace as the wires diverge further up the wall, only to be replaced by another current generated in the transformer.

Focusing on Tesla's technological inventions rather than his equally historic run-ins with protocorporate America (the inventor was a long-suffering victim of Thomas Edison's plagiarism before hooking up with Westinghouse), Sonnier delves into the electrical energy and natural power sources that were Tesla's obsessions. Electrical Fence, 1999, a charged grid of wire stretched from floor to ceiling, isn't a visual tour de force, but considering the invisible power coursing through it, the piece does offer viewers a tingle of danger. Likewise, Electrical Transmitting Apparatus, 1997, a sculpture composed of copper wire, neon transformer cables, and ceramic condensers, isn't much to look at, but it comes with a scary/sexy "high voltage" warning. In the dimmed gallery filled with the snap and buzz of electricity, Sonnier conjures both the mystery of power harnessed and the specter of the solitary Tesla working in his laboratory.

Projected on a wall in the back of the gallery was a 121-minute VHS compilation of Sonnier's film. video, and performance work from 1969--73. Collectively titled "Performance and Formal Light and Color Studies," these videos, much more visually demanding than the sculptures, showcased Sonnier's earlier concerns. Works like Painted Foot: Black Light, 1970, a sixteen-minute shot of a bare foot nudging around in a black-lit space, and the four installments of "TV-Hybrids," 1971, which combine light, color, and counting (a la '60s Structuralist film) are not for the attention-deficient. But they serve as a touchstone for viewers, tracing Sonnier's path from light to its source, pure energy--from the subtle opticality of illumination to works predicated on voltage so powerful it could, quite literally, knock his viewers out.