332 



SCIENCE. 



[N. S. Vol. XIX. No. 478. 



the phenomena were quite brilliant. Ex- 

 cept the phosphorescent sulphides no sub- 

 stances were found whose phosphorescence 

 was diminished by cold. Perhaps the most 

 interesting substance tested was tetrachlor- 

 phthalic acid. This showed both phos- 

 phorescence and fluorescence at ■ — ^186° C, 

 while quite inactive at ordinary tempera- 

 tures. It was also stimulated by Roentgen 

 rays, fluorescing under their influence as 

 brilliantly as a good X-ray screen. 



The Spectro-photometric Study of Fluores- 

 cence: B. L. Nichols and B. Merritt. 

 The authors investigated the spectrum of 

 the fluorescent light from fluorescein and 

 other substances when excited by light of 

 widely different wave-lengths. The spec- 

 trum was found to be the same in all cases, 

 even when the wave-length of the exciting 

 light was greater than that of the brightest 

 region in the fluorescent spectrum. In 

 agreement with Lommel, and in opposition 

 to Lamansky, Beequerel and others, two 

 conclusions are reached, viz., (1) the dis- 

 tribiition in the fliioreseent spectrum is 

 independent of the exciting light; (2) for 

 substances of this class Stokes's law does 

 not apply. 



The Electrical Conductivity of Liquid 

 Films: L. J. Briggs and J. W. McLanb. 

 The thickness of films of Plateau's solu- 

 tion was computed from the area and 

 weight, and the resistance of the films was 

 directly measured. It was found by this 

 method that the specific conductivity of 

 films about 1 p. thick is less than one third 

 that of the solution in mass. 



On the Use of Nickel in the Marconi Mag- 

 netic Detector: A. L. Foley. 

 A detector with a core of nickel wires 

 was found to have about the same sensi- 

 tiveness as one using iron. The greatest 

 sensitiveness was obtained by using a core 

 containing both nickel and iron wires. 



On Double Refraction in Matter moving 

 through the Ether: D. B. Brace. 



Electric Double Refraction in Gases: D. 



B. Brace. 



The author presented a brief prelim- 

 inary account of work on the subjects men- 

 tioned in the two titles above, but looked 

 upon the experiments as not yet carried 

 far enough to make a detailed report de- 

 sirable. 



The Work of the National Bureau of 

 Standards: E. B. Rosa. 



The Spectrum of the Afterglow of the 



Spark Discharge in Nitrogen at Low 



Pressures: Percival Lewis. 



The phosphorescence studied is produced 

 only in the purest obtainable nitrogen. 

 Instead of a continuous spectrum, which is 

 observed in most cases of afterglow, the 

 light in this case gave a banded or line 

 spectrum. The spectrum contains a num- 

 ber of unidentified lines, of which four in 

 the visible region are especially prominent". 

 Certain of the lines of nitrogen, mercury 

 and aluminium (the last due to the elec- 

 trodes) were also present. 



J. J. Thomson has advanced the hypoth- 

 esis that afterglow effects are due either 

 to chemical actions in a mixture or to 

 polymeric changes in a pure gas. If this 

 be the explanation — and it seems a reason- 

 able one— how can a chemically neutral gas 

 excite luminosity in every metallic vapor 

 which may be present, such as mercury 

 and aluminium? 



The Spectrum of the Electrodeless Dis- 

 charge in Nitrogen: Percival Lewis. 

 The discharge was obtained in the form 

 of a ring by the use of an oscillatory dis- 

 charge in a coil surrounding the tube. Any 

 effects due to electrostatic influences were 

 eliminated by screens of moistened paste- 

 board. The spectrum showed the bands of 

 the second and third groups, as classified 



