Word: spectrum
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Dates: during 1910-1919
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...Physical Colloquium. "Bohr's Theory and the Spectrum of Helium," by Professor Lyman and Dr. D. L. Webster. Jefferson Physical Laboratory, Room...
...simple linear quantitative relationship between the exact amount of radioactivity and the atomic weight was found. The ultra-violet spectrum of a typical specimen appeared to be exactly identical with that of ordinary lead. The necessary inference seems to be that lead from radioactive sources consists of a mixture of at least two substances, of which one is ordinary lead. The foreign substance must be very similar to ordinary lead and very difficult if not impossible to eliminate by chemical means; for many precautions were taken to purify the samples. This substance cannot be identified in the ultra-violet spectrum...
...being connected with undergraduate departments, the work of the Harvard Astronomical Laboratory, famous in all parts of the world for the valuable results of its observations, is not familiar to undergraduates. The studies of the Observatory might be roughly classified as Position, Motion, Brightness, Spectrum, and Color, all elements in the task of finding, classifying and determining the composition of the heavenly bodies...
...establishment of the Henry Draper Memorial Fund has made possible the study of the spectrum of the stars. The Observatory has been eminently successful in this work and a classification was drawn up which was accepted last summer by the International Solar Union at Bonne to be the authentic system. In this work, a large number of new stars, variables and other peculiar objects have been discovered. A catalogue classification of 200,000 stars is now being prepared at the Observatory by Miss Cannon at the rate of 5,000 a month. This will fill eight volumes of the annals...
...Physical Colloquium. "The Ionisation of Gases by Light and the Spark Spectrum of Aluminum," by Professor Lyman, in Jefferson Physical Laboratory, room...