The Mogul 3-Way Bulb: Big Light for Large Rooms

A standard bulb was never meant to light a room the size of a parlor. The mogul base was, and the mogul 3-way bulb is why big rooms could be lit, and adjusted, from a single socket. The common Edison screw handled household lamps; the mogul, a bigger screw base built for higher wattage, carried the heavy output that large rooms needed. It ran in factories and theaters first, then came home in the 1920s, inside torchieres and the tall table lamps that anchored a living room.

Range from one socket

Pair that base with a 3-way bulb and you get the part people remember: low, medium, full, from one turn of the socket. It answered a real problem, how to give a single lamp the range a big room needs across an evening, and it did it without dimmers, without rewiring, without much of anything to break. The system lasted because the cleverness sat in the right place. The intelligence was in the socket and the bulb, not the fixture, so the fixture itself could be beautiful and simple and last a century.

A second life

What did fail, in the end, was the bulb supply. High-wattage mogul incandescents got scarce, and the ones you could find ran hot and pulled a lot of current. Period-correct mogul 3-way LED bulbs now give the same low-medium-full range at a fraction of the heat and draw, behind the same vintage glass, in the same original socket. The look doesn't change. The power bill does.