28 Baskerville and Kunz — Kunzite. 



The same is the case if pulverized wollastoirite or pectolite be 

 used instead of the kunzite. When either of these mixtures is 

 put in a Bologna flask and laid on a heated metal plate (less 

 than red-hot), the powder becomes incandescent and remains so 

 for a long time after removal. 



These three minerals phosphoresce by heat alone, as was men- 

 tioned above in regard to kunzite. Perhaps this luminosity of 

 the mixed powders at the ordinary temperature may be 

 accounted for in part by the evolution of heat* on the part of 

 the radium compounds, but there are experimental reasons 

 which cause us to reject such explanation for the total effect. 



The emanation of radium, the a-rays, according to Ruther- 

 fordf are condensed at a temperature of— 130° to — 140° C. 

 The emanations were driven from radium chloride by heat and 

 condensed with liquid air on a number of kunzite crystals, 

 according to a method which will be described by one of us 

 (B) and Lockhart in another paper, and no phosphorescence 

 observed. Consequently kunzite responds only to the y-rays, 

 which are believed to be virtually Roentgen rays. 



6. Actinium. — A sample of the still more rare and novel 

 substance disco verd by Professor DebierneJ and received from 

 him through the courtesy of Professor Curie, was also tried as 

 to its action upon kunzite and some other minerals. The 

 actinium oxide, with an activity of 10,000 according to the 

 uranium standard, gave off profuse emanations and affected 

 diamonds, kunzite and willemite in a manner similar to the 

 radium salts, with quite as much after-continuance. However, 

 we have not tried the condensation of these emanations upon 

 the minerals by refrigeration. 



The peculiar properties of the kunzite variety of spodumene, 

 which have been enumerated, have not been observed in any 

 other of the gem or gem-minerals that we have examined. It 

 is barely possible that the small amount of manganese may 

 have much to do with it, but from our present knowledge 

 basing a chemical explanation thereon is idle. 



*P. Curie and Laborde, Comptes Kend., cxxxvi, 673. 

 fPb.il. Mag., v, 561. JCompt. Rend., cxxix, 593. 



