Illumination items: By the lighting and illumination committee: Illumination — Production tests in the industries

Recently conducted illumination-production tests covering a wide diversity of operations in various industrial plants demonstrated in a larger field than ever before the value of higher intensities of illumination and more uniform distribution of light. Among the tests shown in Table I, special interest is attached to the result of the investigation recently made in the United States Post Office Department. In that investigation conducted by the Office of Industrial Hygiene of the United States Public Health Service, it was definitely ascertained that when 8 foot-candles of illumination replaced the 3.6 foot-candle level, there resulted an average increase of 4.4 per cent in the work of the letter-separators.