136 MR. H. WILDE ON THE 



antimony, and bismuth are better represented by the 

 formula H^n, and that Cu, and Zn, in the series Hn, 

 and Il2n, exhibit the same constant minus difference from 

 the classical atomic numbers as B, P, and V, are further 

 indications of some unknown property of the elements 

 which conceals their exact multiple relations from view. 

 If the discovery of two new elements of this group by 

 Hermann *, to which this chemist has given the names of 

 neptunium and illmenium, be confirmed, the former element 

 will have an atomic weight of 140, and the latter element 

 an atomic weight of 165, as shown in the table. 



Although the numerical relations of the members of the 

 series H5W are very interesting, yet, it will be seen that 

 the ratios are not so simple as those of the series Hw, Hm, 

 H3W, as multiples of the second member, minus the first, 

 do not give the atomic weights of the other members of 

 the series. 



The series H4W is incomplete, not only by reason of the 

 absence of several of its members, but also because the 

 atomicity of lanthanum and didymium is not yet agreed 

 upon by chemists. There can, however, be no question as 

 to the position of titanium as the third member of this 

 series, as there is no other place vacant where an element 

 with an atomic weight of 48 would fit, while the isomor- 

 phism of rutile with cassiterite and zirconia indicates the 

 relation of tin and zirconium with the same series. 



The classification of uranium presents some difficulty 

 on account of the fewness of its analogies with other 

 elements, but there can be little doubt that the atomic 

 weight assigned to U= 120, until recently, is much too 

 small, as there are no elements with atomic weights so 

 low, correlated with specific gravities so high as that of 



* 'Nature,' April 12th, 1877. H. Kolbe's 'Journal fur praktische 

 Chemie,' Feb. 1877, pp. 105-150. 



