1 8 Ramsay, The Newly Discovered Elements. 



Now, the density actually found for impure xenon was 

 32"5, a number which implies an atomic weight of at least 

 65 ; it will be noticed, however, that 65 is the atomic 

 weight of zinc, and that there follow in order gallium, 70, 

 germanium, 72, arsenic, 75, selenium, 79, and bromine, 80; 

 and that the first gap in the table occurs between bromine 

 and rubidium, as before stated. It is highly probable 

 that when the xenon has been sufficiently purified, its 

 density will prove to be about 41, implying an atomic 

 weight of 82. If this turns out to be the case, it will 

 furnish an additional proof of the correctness of the 

 interpretation of the theoretical ratio of specific heats, 

 on the kinetic theory of gases. 



In conclusion, it will be remarked that there is still 

 room for an element with atomic weight 130 to occupy a 

 position between iodine and caesium. I do not despair of 

 its being found, possibly in air. It is not unlikely that it 

 may be present in extremely minute amount, for its 

 boiling point will doubtless lie not far below zero 

 centigrade. We may not unfairly expect a ratio between 

 the boiling points of neighbouring elements, such as the 

 followinsf : — 



[Fluorine 



Chlorine 



Bromine 



Iodine 



Neon 



Argon 



Xenon 



? 



°Abs. ... 

 °Cent.... 



88 

 -185 



238 



-35 



332 



+ 59 



457 

 + 184 



— 241 



86 

 -187 



123 



-150 



169 



- 104 



With full acknowledgment of the speculative nature of 

 this inquiry at the present stage, one fact is certain ; that 

 the boiling point of argon lies 152*^ lower than that of its 

 neighbour, chlorine. We are well aware, from countless 

 examples, that the boiling points of all substances are raised 



