The Astrophysical journal . sparent toX 1250 Angstrom units. While colorless fluorite is in general farmore transparent than the tinted varieties, yet colored fluorite doesexist of sufficient transparency to serve in apparatus intended for theexploration of the region between X 2000 and X 1250. Quartz in thicknesses of from 1 to 2 mm is transparent to X is a useful fact, as it indicates that quartz windows may beemployed to replace fluorite in those cases where the electric orphysiological action of the strong portion of the hydrogen spectrumlying near X 1600 is to be studied. Of all
The Astrophysical journal . sparent toX 1250 Angstrom units. While colorless fluorite is in general farmore transparent than the tinted varieties, yet colored fluorite doesexist of sufficient transparency to serve in apparatus intended for theexploration of the region between X 2000 and X 1250. Quartz in thicknesses of from 1 to 2 mm is transparent to X is a useful fact, as it indicates that quartz windows may beemployed to replace fluorite in those cases where the electric orphysiological action of the strong portion of the hydrogen spectrumlying near X 1600 is to be studied. Of all the substances examined none show absorption bands inthe region between X 2000 and X 1250. The apparatus employed inthis examination, however, does not permit the investigation of thispoint by methods of great delicacy. It is interesting to note that the fluorescent substance willemite responds to the action of light of extremely short wave-length. Jefferson Physical Laboratory Harvard University December 26, 1906 PLATE II. GEORGES RAYET Minor Contributions and Notes GEORGES RAYET Science has suffered a severe loss in the sudden decease, on June14, 1906, of M. Georges Rayet, founder, and for more than twenty-five years director, of the Observatory of Born at Bordeaux on December 12,1839, he became attached to theObservatory of Paris in 1862. Here he was more particularly occupiedwith the weather service, but he was also attracted by spectroscopy,then a new branch of research, and he undertook the spectroscopicstudy of numerous celestial objects. His published works during thefollowing years deal with the spectrum of the Sun, prominences, andsun-spots; with the spectra of several comets, and with terrestrialmagnetism and auroras. Some of his investigations were made inconjunction with M. C. Wolf, and together, in 1867, they discoveredthe three stars in Cygnus having bright lines in their spectra. Thenames of MM. Wolf and Rayet have been always associated with thespec
Size: 1400px × 1785px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectspectru, bookyear1895
