Manchester Memoirs, Vol. Ivii. (191 3), No. \% 9 



common difference of 23 between the atomic weights of 

 the series H« (commencing with K) to the final member 

 Hg. In like manner there is a common difference of 24 

 in the strictly parallel series H2«. The regular parallel 

 differences between the atomic weights of members at the 

 head of both series are equally remarkable. 



I have discussed in former papers the alternation of 

 light and heavy metals in regular order observable in 

 each of these series, and have put forward suggestions as 

 to its possible cause in my first papers on the " Origin of 

 Elementary Substances," published by the Society in 

 1878 and 1887. 



Radium (as was indicated in my Table of Elements 

 some years previous to its discovery), is one of the 

 synthetic transformations of helium in the series H2w, and 

 is the next higher member to barium of the alkaline-earth 

 metals. This place has since been assigned to radium by 

 Mme. Curie, but with an erroneous atomic weight and 

 specific gravity ; as will be seen by comparison with the 

 similar properties of the other members of the same series. 

 Helium (H2) is also shown in the paper of 1878* as 

 the analytic transformation ultimate of radium and other 

 members of the series ¥i.2n. 



The positions of helium and neon in my general Table 

 of Elements, as the transformation ultimates of the series 

 H2« and Wjn respectively, are further interesting in con- 

 nexion with the recent announcements that these elements 

 have been found in glass vessels in which they had no 

 previous existence.^ Now, assuming the reality of these 



* Proc. Manchester Literary and Philosophical Society, vol. xvii, p. 194, 

 1878 ; Memoirs, vol. xxx, 1887. Chem. Neivs, vol. 38, 1878. 



t Naiiire, February 13th. Chem. News, February 14th, 1913. 



