Serving as a night-light over the fire trucks, it has only been turned off briefly on three occasions when it was moved. The four-watt bulb was handblown with carbon filament by Shelby Electric Co., a manufacturer that was purchased by General Electric in 1914.

"It's not surprising that a company that made bulbs to last a hundred years went out of business," says local historian Barry Schrader. The bulb's date of origin, 1901, has been authenticated by local records, and it has been recognized by both the Guinness Book of World Records and Ripley's Believe It or Not. Engineers from General Electric have inspected the bulb and declared it representative of the time it was made, says Tom Bramell, deputy fire chief.

Engineers say the bulb has survived due to a combination of the filament thickness and the low wattage. "It may be a freak," Schrader says, "but it is also a marvel."

Firefighters happily show off their prize to visitors. As one of them says, pointing to the bulb, "It's always neat to look at a good thing we don't understand, something that's still living but isn't supposed to be."

Livermore residents treat the bulb with the awe normally reserved for a Fabergé egg.