The latter were made by General Electric. Like the nice-looking cars seen along this nice Pennsylvania downtown street, most of the vehicles and mercury street lights are long gone. Newer high-pressure-sodium street lights (having a yellowish glow) were more energy efficient than the mercury vapor ones (bluish-glow). Widespread changeouts took place commencing during the 1980s making the some of the vintage mercury ones rather desirable today.

Added note, just fyi...I collect and research old street lights, like I do with insulators. Always did. For educational purposes (ONLY) please refer to my website: http://www.vintagestreetlights.com for additional information regarding mercury vapor and incandescent street lights, the lightbulbs and other almost-forgotten accessories once used with them.