An elementary book on electricity and magnetism and their applications . Fig. 327. — Distribution of light. Curve Awithout shade, curve B with shade. ELECTRIC LIGHTING 465. Fig. 328. Distribution curves for a magnetite arc; A, lamp alone, B, withproper devices. 318. Measurement of illumination. In these days when wedo so much of our work and play by lamplight the problem ofillumination is a very vital one. In the first place, it is essen-tial to have enough light to see things distinctly, but, further-more, experience shows that we may have enough light andyet not be able to distinguish the po
An elementary book on electricity and magnetism and their applications . Fig. 327. — Distribution of light. Curve Awithout shade, curve B with shade. ELECTRIC LIGHTING 465. Fig. 328. Distribution curves for a magnetite arc; A, lamp alone, B, withproper devices. 318. Measurement of illumination. In these days when wedo so much of our work and play by lamplight the problem ofillumination is a very vital one. In the first place, it is essen-tial to have enough light to see things distinctly, but, further-more, experience shows that we may have enough light andyet not be able to distinguish the position and shape of ob-jects well, because the lamps are not properly distributed tocast such shadows as we are accustomed to. Then there isthe very difficult problem of getting lamplight which willgive colored objects the same appearance which they have indaylight, Finally, we have to protect our eyes from the glarecf the modern powerful electric lamps, which are likely to giveus too much light in spots. Besides these purely physicalaspects of the problem of illumination we have the economicquestion of its cost. We have already seen that the unit of intensity for a
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmagnetism, bookyear19
