Manfacturer: General Electric Co.
Here is one of GE's vintage Bonusline mercury vapor lamps. Mercury vapor lamps were the cutting edge in lighting technology in the 1950s. Popularity of these lamps for street lighting also exploded during that time. Mercury lamps were twice as efficent as the incandescents they replaced, and also lasted much longer. There was one drawback however. Mercury lamps had poor lumen maintenance due to heavy blackening on the arc tube ends, caused by evaporation of the electrode emission material. However since mercury was still the cutting edge in those days, the engineers at the lighting manufacturers were constantly doing research to retard arc tube blackening. They achieved the goal by engineering the arc tube so that the emission sputtering would turn white on the quartz wall instead of black, so the lamp can stay bright for a longer period of time. GE was so proud of this achievement they called their lamps Bonusline. All of GE's mercury lamps manufactured from 1961 to around 1966 were marked with this name. This lamp was manufactured in December 1964, well within the Bonusline period. Also present is the BT-37 envelope. GE was like Westinghouse and Sylvania in those days doing only BT shapes. In late 1965 GE finally went to the E shape. They kept the BT-37 shape as an option for the 400 watt mercury lamp for many years after 1966, maybe still do!
This lamp was used in a GE Form 400 for many years, and I still have that Form 400 too! This Bounsline lamp still works but kind of dimmed out.
Here's the Bonusline etch. Later GE BT lamps had the etch on the side just above the neck. Although hard to see, there is a "2" just southeast of the "E", the last letter of the trade name. The "1" and "2" represent the date code for this lamp. Later GE etches had the two digit date codes clumped together.
Lamp: Mercury Vapor Lamp
Wattage: 400 watt
Starting Voltage: 240 volts
Operating Voltage: 130 volts
Ballast Type: H-33
Color Temperature: 5700K
CRI: 15
Light Output: 21,000 Lumens
Bulb: BT-37 Hard Glass
Finish: Clear
Base: E-39s Brass Mogul Base
Class: -
Filament: -
Lamp Life: 16,000 hours
Manf. Date: December 1964
Country of
Orgin: USA
