The American Museum Journal 



Vol.. IV. JANUARY, 1904. Xo. i 



|HE Supplement issued with this number of the 

 Journal takes the form of a General Guide to the 

 exhibition halls of the Museum. It has been pre- 

 pared for the purpose of facilitating a rapid sur- 

 vey of the collections which have been placed on 

 viev\-. Those halls which have already received extended treat- 

 ment in the Supplements of the Journal are passed over with 

 few words, in order to devote more space to the remainder. The 

 twelve Guide Leaflets which have preceded this one will be 

 found to supplement it in as many important directions. Other 

 Guide Leaflets to special exhibits and to the halls as units are in 

 course of preparation, and will be issued from time to time. 



THE BEHAVIOR OF THE MINERALS AND GEMS OF THE 



MORGAN COLLECTIONS TOWARD RADIUM AND 



OTHER SOURCES OF LIGHT. 



During the past summer, Dr. George F. Kunz, Honorary 

 Curator of Gems, and Professor Charles M. Baskerville, Professor 

 of Chemistry in the University of North Carolina, made a care- 

 ful study of the action of ultra-violet light. Roentgen rays and 

 radium upon the specimens in the Bement-Morgan and Tiffany- 

 Morgan collections. These collections are the most complete of 

 authenticated minerals and gems on exhibition in the country 

 and give a unique opportunity for the observation of fluores- 

 cence and phosphorescence resulting from treatment in the 

 manner indicated. In all, about 13,000 verified minerals and 

 gems in these collections were carefully studied. In addition 

 to these, the investigators submitted to the sources of radio- 

 activity selected stones from about 15,000 British Guiana dia- 

 monds, and two particularly handsome diamonds, one of which 



