ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably 

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 this issue. 



PHYSICS. — Distribution of energy in the visible spectrum of an acety- 

 lene flame. W. W. Coblentz and W. B. Emerson. Bureau of 

 Standards Scientific Paper No. 279 (Bull. Bur. Stds., 13: 355-364). 

 1916. 

 Data on the distribution of energy in the visible spectrum of a 

 standard source of light are frequently needed in connection with inves- 

 tigations in physiology, in psychology, and in physics; especially in 

 photoelectric work, in photography, and in the photometry of faint 

 light sources. Frequent requests for such data have come to this 

 Bureau. The acetylene flame appears to be a promising source of 

 light having a high intensity and a white color. The present paper 

 gives data on the distribution of energy in the visible spectrum of a 

 cylindrical acetylene flame, operated under specified conditions. 



In the region of the spectrum extending from the yellow to the 

 violet the spectral energy distribution of all the flames examined 

 appears to be the same, within the limits of observation. On the 

 other hand, in the region of the spectrum extending from the red toward 

 the long wave lengths the emissivity is greatly affected by a variation in 

 thickness of the radiating layer of incandescent particles in the flame. 

 Hence, in and beyond the red part of the spectrum the data apply only 

 to cylindrical flames which are operated under specified conditions. 



w. w. c. 



PHOTOMETRY. — An interlaboratory -photometric comparison of glass 

 screens and of tungsten lamps, involving color differences. G. W. 

 Middlekatjff and J. F. Skogland. Bureau of Standards Scien- 

 tific Paper No. 277 (Bull. Bur. Stds. 13: 287-307). 1916. 

 In 1911 the Bureau of Standards and the National Physical Labo- 

 ratory of England, in cooperation, established groups of 1.5 wpc tung- 



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