2 Wilde, Atomic Weights of Neon, Argon, Krypton, Xenon. 



The densities assigned to these elements, including 

 argon, are : — 



Neon. Argon. Krypton. Xenon. 



9-96 19-96 4078 64 



M. Berthelot and other chemists have shown that, 

 within the limits of experimental error and residual inter- 

 ferences, argon is one and a half times as dense as nitrogen, 

 and stands in the same relation to this element as ozone 

 does to oxygen, with similar exaltation of their inert and 

 active properties respectively. For the like reasons that 

 determined the density of argon to be 21, the density of 

 krypton is 42, and of xenon 63. 



Now as the atomic weights of all elementary gases, 

 at ordinary temperatures, are expressed by the same 

 numbers as those of their densities, the atomic weights of 

 argon, krypton and xenon (21, 42, 6-}^^ form a definite 

 triad like those of the alkaline metals and of several 

 other series of elements. Moreover, these numbers clearly 

 establish the new gases as members of the series H/n, 

 as 3 X H7 = 2i : 6x H7 = 42 : 9x^17 = 63. The multiple 

 numbers 3, 6, 9, also form a triad similar to that of the 

 atomic weights of the three gases. 



Although the density of neon is at present anomalous, 

 I have ventured to identify this element as the first 

 member of the series H7n, with an atomic weight equal 

 to 7. The great difficulty experienced in isolating 

 neon from its denser congeners, may probably have 

 prevented the atomic weight of this gas from being more 

 approximately determined. 



The members of the series H7n in my table of 

 elements, arranged with their atomic weights in multiple 

 proportions, now stand in the following order : — 



