File:Light and lighting (1908) (14765582815).jpg

Identifier: lightlighting13illu (find matches)
Title: Light and lighting
Year: 1908 (1900s)
Authors: Illuminating Engineering Society Association of Public Lighting Engineers (Great Britain)
Subjects: Lighting
Publisher: (London)
Contributing Library: Knox - University of Toronto
Digitizing Sponsor: University of Toronto

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ce ofcontrast or colour relief ? Is Elworthy (7)right when he lays the greatest stress onthe lack of colour relief or are lightabsorption and feebleness of illuminationthe chief factors ? Seasonal prevalence. Why, as Dransart, (8) Elworthy, ()Ohm (9) and myself (2) have pointedout, should nystagmus be more commonin the winter months ? Ohm accepts myexplanation that in winter the absence ofsunlight (coal workers in the old daysrarely saw the sun except on Sundays)interferes with the normal formation ofpigment in the retinal cells. Stassen (•)says that nystagmus is commoner amongmen working by day. Think of thecolourless plant striving to grow in thecellar and of the nystagmus of albinoes.I think also that miners* nystagmus iscommoner in men with fair hair and lightcoloured eyes. G\are. Although glare is generally associatedwith light of great intensity, in the lowillumination of a coal mine any diiv< trays of light which fall into the eye 72 THE ILLUMINATING ENGINEER (march, 1920)
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FlG. 7.—Setting a pair of Timbers. produce inconvenience, amounting inthe case of the nystagmic worker, todiscomfort or even pain. Many colliersalso work in a reclining position with thelamp at their feet, so that the light shinesobliquely into their eyes. It is knownthat the effect of glare is increased whenthe source of light has a black back-ground and diminished when a whitereflector is used. Very few colliers willwork at the coal face with a reflectoras the amount of working area illumin-ated is too small necessitating frequentchanges in the position of the lamp.Mr. Turner of the Stafford Companygave a man working on a coal cuttera bulls eye miners rescue lamp. Theman refused to use the lamp after thefirst day, his reason being that he hadto keep changing the position of the lampcontinually. Would it be possible, how-ever, by the use of a very large reflectorwith a matt surface to give a diffusedlight over a comparatively large areaand so avoid glare ? Quality of light. It has

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