This old street light goes back to between 1953 and 1956 and utilized a 100 watt mercury vapor bulb. These were pretty uncommon and very expensive in their day, making survivors indeed a rarity! This one illuminates nightly, like the other vintage street lights around my yard that I am sharing photos of. Mercury vapor bulbs are twice as energy-efficient as filament ones; and they last much longer. These features made them an attractive and economical choice for street and industrial lighting soon after WW2 ended.