The same illuminating effect will be regarded as
attainable by means of candles aggregating only 35 per cent., or small
electric glow-lamps aggregating 77 per cent., or large electric glow-
lamps and flat-flame gas-burners aggregating 90 to 95 per cent. of this
candle-power; while if sources of light of higher intensity are used,
such as Osram or Tantalum electric lamps, or the larger incandescent gas-
burners (the Welsbach "C" or "York," or the Nos. 3 or 4 Welsbach-Kern
upturned, or the No. 1 or larger size inverted burners) or incandescent
acetylene burners, it will be assumed that their aggregate candle-power
must be in excess by about 15 per cent., in order to compensate for the
impossibility of obtaining equally well distributed illumination. These
assumptions are based on general considerations and data as to the effect
of sources of light of different intensities in giving practically the
same degree of illumination in a room; it would occupy too much space
here to discuss more fully the grounds on which they have been made. It
must suffice to say that they have been adopted with the object of being
perfectly fair to each means of illumination.
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