80 Baskerville and Kunz — Rare Earth Oxides. 



kunzite,* with radium-barium chloride (240 activity) and car- 

 bonate (100 and 40 activities). All gave good luminosity. 



It may be recalled that in a previous communication it was 

 stated that of the oxides mentioned above when submitted to 

 the action of ultra-violet light, only two of them became phos- 

 phorescent, namely, zirconium and thorium dioxides. 



Further, it should be noted that one of these oxides is not 

 radio-active, namely, zirconium dioxide, while thorium dioxide 

 is ; also that uranium oxide, which is radio-active, does not 

 respond to the ultra-violet light. Is it possible that we have a 

 common constituent in zirconium and thorium that differs 

 from, the others and still is different from the constituent 

 which makes uranium, responsive f 



It has been frequently noted and is well known that chloro- 

 phane is extremely sensitive to ethereal or mechanical stresses, 

 giving evidence of such sensitiveness by luminosity. We have 

 learned, as will be published later in full, that chlorophane 

 contains yttrium and ytterbium. Neither of these oxides 

 responds either to the ultra-violet light or the radium ; hence 

 we cannot attribute the sensitiveness of chlorophane to their 

 presence. Is it not possible that we have here, as well as in 

 willemite and the other zinc compounds mentioned, a new sub- 

 stance, perhaps elementary, which acts as a radium foil, as it 

 were f 



We propose to carry on further the investigation of these 

 matters. 



* This contains zinc as will appear shortly in the completed analysis by 

 one of us (B) and Davis. 



