Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 607
Electrical Engineers, .July, 1912. The necessity for proper maintenanceis shown by the following example.In one large system of 10,000 tungstenlamps the losses of light per day dueto dust and dirt interpreted intomoney values might amount to twentydollars a day—or.§7,500 per annum. Tiie author also… … Figs. 2-4, showing typical ceilings in factories. lighting. For example, the wages for■si.f minutes per day in average shops\\-ould pay, not only for meagre, butfor entirely adequate illumination. Nowthe improved efficiency due to thesubstitution of good lighting condi-tions for bad one.s should…
Lighting
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
