200 CARNEGIE INSTITUTION OF WASHINGTON, 



(57) In harmony with previous results, the brightness of the 

 night sky does not appear to be due exclusively to direct starlight. 



(58) Nearly 300 helium stars between galactic latitudes ±30° 

 and longitudes 217° to 360° apparently belong to a single group. 



(59) Over 200 stars in the cluster N. G. C. 1647 show a systematic 

 change of color index with magnitude, indicating that the fainter 

 stars are redder than the brighter ones. 



(60) This fact, together with a large mass of evidence gathered 

 from various independent sources, strongly indicates that light is 

 absorbed in its passage through space, and promises to afford a 

 method of determining the order of distance of the most remote stars. 



(61; An investigation of the luminosity curve for stars of various 

 spectral types is providing data for the study of the arrangement of 

 stars in space. 



(62) In the electric-furnace spectra of iron and titanium 512 

 iron lines and 625 titanium lines have been classified on the basis of 

 their change of intensity with temperature. 



(63) The blue end of the furnace spectra of both iron and titanium 

 first appears at a lower temperature than the red end, and the dis- 

 tribution of line intensities does not resemble the intensitj^ gradation 

 of the continuous spectrum of an incandescent solid. 



(64) Lines of a certain class are relatively much weaker in the arc 

 than in the furnace spectrum. 



(65) The banded spectrum attributed to titanium oxide does not 

 appear in the furnace spectrum at reduced pressure, thus confirming 

 the view that it belongs to the oxide. 



(66) Enhanced lines appear with great strength in the low-voltage 

 "tube-arc" spectrum, which also contains hydrogen lines and the 

 line spectrum of carbon. 



(67) The production of the enhanced lines seems to be related 

 to the high degree of ionization in the ''tube-arc." 



(68) Ionization currents in the electric furnace fall rapidly with 

 increase of pressure up to 4 atmospheres, after which they decrease 

 slowly, and are still appreciable at 20 atmospheres. 



(69) Many lines which are sharp and narrow in the center of the 

 arc show great widening and lack of symmetry at the negative pole, 

 together with marked increase of intensity. 



(70) A general investigation of the Zeeman effect for iron, chrom- 

 ium, vanadium, and nickel has yielded valuable data for the inter- 

 pretation of solar phenomena. 



(71) The chromium line X4254 is split into 21 components by a 

 very intense magnetic field. 



(72) Koch's recording micro-photometer has proved to be of 

 great value in the study of the intensities and displacements of solar, 

 stellar, and laboratory spectra. 



