Bryn Mawr College monographs . rest period of 20 minutes between each testThis was done with all observers on several days under each system of lighting em-ployed. The rest period was taken in each case in a room lighted by daylight, withthe observer facing a wall with an evenly lighted matt surface. For a single seriesof five tests the variation in the time seen clear in the 3 minute periods havealways fallen within i per cent, for all of the observers we have used and for alljsystems of lighting. TRANSACTIONS OF ENGINEERING SOCIETY 462 k classes. The units employed were chosen
Bryn Mawr College monographs . rest period of 20 minutes between each testThis was done with all observers on several days under each system of lighting em-ployed. The rest period was taken in each case in a room lighted by daylight, withthe observer facing a wall with an evenly lighted matt surface. For a single seriesof five tests the variation in the time seen clear in the 3 minute periods havealways fallen within i per cent, for all of the observers we have used and for alljsystems of lighting. TRANSACTIONS OF ENGINEERING SOCIETY 462 k classes. The units employed were chosen rather to show theeffect of varying the factors Ave have grouped under the headingof distribution on the ability of the eye to maintain its efficiencyfor a period of work. We hope ultimately to determine the CHART I.—Distribution the effect on loss of efficiency of varying the observers position in the room, or the number of bright sources, primary and secondary, in the field of vision. POSITION I POSITION II.
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Keywords: ., bookauthorbrynmawr, bookcentury1900, bookdecade1900, bookyear1901
