School lighting / by Elwin H.T. Nash ; issued by the Medical Officers of Schools Association.

  • Nash, Elwin H. T.
Date:
1914
Catalogue details

Licence: Public Domain Mark

Credit: School lighting / by Elwin H.T. Nash ; issued by the Medical Officers of Schools Association. Source: Wellcome Collection.

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    furthest desk is by measurement of the angle made with either the floor or the top of the desk and the top of the window, which should be from 25 to 27 degrees with the horizontal. Rutzicka, of Praga, and Pleier, of Carlsbad, tried to ascertain the proportion of light admitted to the school-room Fig, 9. Cenrra. Hace A CORR/DOR Aig CL -FRANCE SCALE FEET 72 ° J ° fo by taking the photometric readings of the zenith and of the illumination of the desks in the room. Difficulty was found in dealing with the high figures given by the zenith in addition to the rapid variations. Rutzicka laid down the average illumina- tion to be 2000 M.K., and 20 M.K. as the minimum which should be found on any desk, that is, 1 per cent. of the zenith intensity. When we came to investigate these measurements we found that owing to the very high values obtained of the zenith readings, we could get no satisfactory relationship to the
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