10/14/2026
Another great find from 328 Market, somehow in great condition despite being covered by the elevator, in the dirt, in the basement.
This antique incandescent light bulb appears to date to approximately 1900, and may be an Imperial Bryan-Marsh lamp, although the manufacturer has not been definitively confirmed. The bulb features a tall, elongated, pear-shaped glass envelope, a threaded metal screw base, and an intact, sealed glass exhaust tip at the top, used during manufacturing to evacuate air and create a vacuum inside the bulb. Inside, the remains of the delicate glass support rods, electrical wires, and a broken filament are visible; the filament appears to have formed an arch and may have been made of carbon, as was common in early incandescent lamps. A handwritten number “20” appears on the internal glass stem, an especially intriguing detail because the Smithsonian National Museum of American History documents a similar Imperial Bryan-Marsh lamp from circa 1900 with the same marking, a pear-shaped envelope, and two arched carbon filaments connected in series. The Smithsonian specimen is rated at 110 volts and 16 candlepower and measures approximately 5 inches long by 2⅜ inches wide. The matching construction and unusual internal marking make this a promising identification, but the exact maker and model remain unverified.