The Old North Church, Boston's 285-year-old beacon of the American Revolution, has gone high-tech with the installation of light-emitting diodes, or LEDs.

Ed Pignone, executive director of the Old North Foundation of Boston, said energy-efficient lights now illuminate ceiling vaults inside the church, whose steeple was used by Paul Revere to display two lanterns as a signal about British troop movements on April 18, 1775- the night described in Henry Wadsworth Longfellow's famous poem, which included the line: "One if by land, and two if by sea."

Old North has been dimly lit by old incandescents, which frequently burned out. The LEDs, on the other hand, are projected to last at least 25 times as long as the incandescent bulbs, at five times the efficiency. They also do not give off as much heat as the older lights, which caused ceiling paint to peel prematurely.

The 18 LEDs strips in the church's sanctuary are tucked into crown molding -- illuminating the graceful white ceiling arches while the lights themselves are hidden from direct view by tourists and worshipers below.

Pignone noted though that LEDs have yet to replace the slightly less-modern compact fluorescents that the church began using two years ago in its modern versions of the steeple lanterns.

The LEDs were donated by Philips Solid-State Lighting Solutions, a company formed through last year's acquisition of Color Kinetics, a Burlington, Mass.-based LED designer, by Netherlands-based Royal Philips Electronics NV.

LEDs are similar to computer semiconductors, but they convert electricity directly to light, rather than heating a metal filament to the point of glowing incandescence. The light streams out of tiny glass domes, about the size of matchstick heads.

They are more expensive than incandescents and compact fluorescents, but are being touted as eventual replacements for those lights because of their growing efficiency and predictions of increasingly lower costs.