at the Royal Iiistitation,\ 1900-1907. 



385 



form of i phosphorus molecule is the origin of the glow or that it 

 marks a 'stage at whi^h some special oxide is formed. The experi- 

 ments of Jungfleisch lead to the conclusion that the cause of the 

 phosphorescence is the oxidation of phosphorus anhydride, but in 

 this apparatus no luminosity was observed when this oxide replaced 

 the phosphorus. 



Fig. 11. 



In any case, the demonstration affords a proof of the narrow 

 range of conditions within which a particular kind of change may 

 occur. I doubt if it afford any proof that oxidation of phosphorus 

 can be effected in the entire absence of " moisture." Phosphoric 



YOL. XIX. (No. 102) 2 c 



