"A Lamp In Reserve"
|Blotter number 220; image number: LAR_B220.
Text on blotter reads:
"A Lamp In Reserve. The best night lighting insurance is an
Edison Mazda chest."
"The Philadelphia Electric Company Supply Dept. 132 South
Eleventh Street, Philadelphia."
At the same time Americans began adopting electric
lights, they also began adopting a new form of transportationthe
automobile. Automotive lighting did not immediately benefit from
electric lamps however. Early carbon filaments were too brittle
to withstand severe shock and vibration. They were also quite dim
and difficult to make to exact electrical and optical specifications.
So early cars used oil or acetylene lamps.
The development of lamps with ductile tungsten
filaments in the years around 1910 changed the situation. Tungsten
filaments could be made small and bright, and they proved tougher
than carbon. Placed at the focal point of a parabolic reflector
(as in the headlight of the car in this blotter), a small tungsten
lamp could throw a beam bright enough to be useful. And unlike oil
or acetylene units, electric lamps did not need refueling.
They did need to be replaced occasionally though. The chest referred
to in this blotter was a convenience package containing a variety
of replacement lamps for headlights, tail lights and panel lights,
all the spare bulbs a motorist might need. Early automotive lamps
did not last as long as today's sealed beam or halogen lamps, and
since streets were generally lighted only in urban areas drivers
were encouraged to carry spare lamps just as they carried spare
tires. Notice that an electrical company rather than an auto parts
supplier sent out this blotter.
For additional information about automotive and street lighting
- Arthur A. Bright, Jr., The Electric-Lamp Industry: Technological
Change and Economic Development from 1800 to 1947 (New York:
MacMillan Co., 1949)
- Sarah Pressey Noreen, Public street illumination in Washington,
D.C.: an illustrated history, (Washington, DC: George Washington