Abstract :
The effect of good light on factory output was demonstrated last winter in a ball-bearing plant. Without the knowledge of the workmen, illumination was raised from five-ft. candles to 20-ft. candles. Production increased 12.5 per cent. Lighting cost per hour in that section of the factory under test was incrased 28 cents and the hourly saving to the company through increased production was $1.47.
