Df.cember 18, 1003. J 



SCIENCE. 



Ill 



an active response; even some that were 

 almost entii-ely altered to steatite. This is 

 especially striking, as some of the specimens 

 from New Jer.sey were loose delicate aggre- 

 gates of needle-like crystals. Some were 

 made up of crystals with a texture like 

 felt; others of coarse crystals, and lastly 

 the pectolite without auj' ciystalline struc- 

 ture, homogeueous, and one time mistaken 

 for jade, from Tehama County, California. 



14. AVollastonite, whether from northern 

 New York or associated with the rosolite 

 garnet from Mexico, phosphoresced mark- 

 edly, and with some duration, with ultra- 

 violet rays, and responded strongly to ra- 

 dium (300,000). 



15. Kunzitc, the new variety of spodu- 

 mene from Pala, California, when exposed 

 to the action of radium of 300,000 activity 

 for a few minutes, became wonderfully 

 phosphorescent, the glow continuing per- 

 sistently after the removal of the source of 

 excitation. Six hundred gi-ams of kunzite 

 crystals were excited with 125 milligrams 

 of radium bromide. Sir William Crookes 

 in a personal letter, having repeated the 

 experiment, remarks: 'I think this lilac 

 variety of spodumeue runs the diamond 

 very close, if it does not surpass it some- 

 times.' Ultra-violet rays caused kunzite 

 to phosphoresce for more than a minute 

 This remark applies to the faded or color- 

 less kind ; the highly dichroic appears to 

 resist. All forms of kunzite become 

 phosphorescent with the Roentgen raj's. 

 So pronounced is this, that a large crystal 

 excited for five minutes afterwards affected 

 the film of a sensitive photographic plate. 

 A thirty-second exposure caused three cut 

 gems to glow first golden pink, then white 

 for ten minutes, 20 times the duration of 

 exposure to the X-raj', the glow penetrating 

 two thicknesses of white paper. Another 

 crystal of kunzite, exposed to the Roentgen 

 rays for ten minutes, was then laid on a 

 sensitive plate for five minutes. The re- 



sulting photograph was clear and distinct, 

 but presented a very curious aspect not 

 seen by the eye, as of a misty or feathery 

 outflow from the side and termination of 

 tlie crystal, suggesting an actual picture 

 of invisible emanations. Kunzite is also 

 pyroelectric, assuming a static charge, 

 similar to topaz, when rubbed with a 

 woolen cloth. It does not phosphoresce 

 when heated. 



16. The action of the quartz group was 

 interesting. As a rule, quartz proper 

 neither phosphoresced nor fluoresced with 

 ultra-violet rays, allowing them to traverse 

 it without any effect. Hence, the very few 

 exceptions noted were doubtless due to the 

 inclusion or iuterniixtiu'e of other .sub- 

 stances. This was apparent in one or two 

 cases of quartz pseudomorphs after barite 

 and fluorite, which phosphoresced, evidently 

 from the presence of some remainder of 

 those minerals. 



Chalcedonic quartz was also very unre- 

 sponsive ; one example only, from Uruguay, 

 S. A., showing a bluish railkj^ phosphores- 

 cence, and a specimen of agate in which 

 one layer responded, between others that 

 did not. 



( Ipal, on the other hand, was freciuently 

 phosphorescent, very rarely fluorescent, and 

 sometimes without any action. The variety 

 quincite phosphoresced intensely, as did 

 also specimens apparently pseudomorphous 

 after gaylussite, which exhibited strong 

 and long continued phosphorescence. 



17. Among carbonates, calcite, witherite, 

 strontianite and barytocalcite all phosphor- 

 esced; and aragonite, with occasional ex- 

 ceptions, was very marked in its action, far 

 surpassing calcite. On the other hand, 

 cerussite did not phosphoresce, save in a 

 single specimen from Pha?nixville, Pa. 



There is here seen again the peculiar phe- 

 nomenon noted in minerals from tlie Lang- 

 ban locality; and the suggestion is evident 

 of the existence there, and at points where 



