THE AMERICAN MUSEUM JOURNAL 



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a zinc mineral gives high luminosity by the application of 



radium, or any other radio-active body. 



The variable action of fluorspar with the various kinds of rays 

 makes it probable that there exists in that mineral either yttrium 

 or 3'tterbium, or some other related rare earth, or perhaps sev- 

 eral of them. 



Some highly active element seems to be present in all of the 

 numerous and complex minerals from Borax Lake, California, 

 but it is not responsive to radium. This is evidently a sub- 

 stance not necessarily radio-active itself, but one possessing the 

 same or allied properties with the substance found with the zinc 

 minerals. A slight exposure for one or two seconds causes all of 

 them to phosphoresce, sometimes for a full minute. 



The substance present in calcite from Franklin, N. J., and 

 from Langban and Pajsberg, Sweden, is probably yet another 

 body, as it does not respond to radium ; although the willemite 

 found with the calcite at Franklin responds in marked degree 

 not only to radium, but also to actinium, polonium. Roentgen 

 rays and ultra-violet rays. The willemite, furthermore, is tribo- 

 luminescent, emitting light even when struck against the side of 

 a glass full of water. When pow^dered, this mineral serves 

 admirably for radio screens, being almost if not quite as good 

 for this and similar purposes as the artificial platinum-barium 

 cyanide. The new lilac-colored spodumene from California, 

 named kunzite by Professor Baskerville {Science, September 4, 

 1903), responds wonderfully to the influence of radium, actinium, 

 polonium, Roentgen rays and ultra-violet rays, and is strongly 

 pyro-electric. 



There probably exists in autunite, and another yellow-brown 

 uranium mineral from Texas, a fluorescent substance which dif- 

 fers from anything elsewhere noted in the collection. 



In the hyalite, from San Luis Potosi, a volcanic mineral, 

 there is present something that responds with a beauty of color 

 that strikingly reminds one of nitrate of uranium; this may be 

 still another substance. 



The most responsive of all, however, whether to radium, 

 actinium, polonium. Roentgen rays, ultra-violet rays or mag- 



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