a website collaboration between Science Service and the Smithsonian Institution

1948 - instrument measures the light output of streetlights from all angles with mirrors


CD 1966022 E&MP27.108

Electric Lighting

July 26, 1948

This instrument in the General Electric Illuminating Laboratory, Schenectady, N.Y., measures the light output of streetlights from all angles.

The mirror, reflecting the image of the engineer making a test, may be moved through a full circle around the light.

At any point in the circle, light beams striking the mirror are reflected to an electric eye 25 feet away, which measures the light coming from the luminaire at that particular angle.

The object of the test is efficiency -- to make sure that the light goes where it is needed most 

Original Caption by Science Service
General Electric

National Museum of American History


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