Minic/ics/cr Memoirs, Vol. Ixi. (iQt/J. 'No. S. 



VIII. On the Atomic Weight of Tellurium in Relation to the 

 Multiple Proportions of the Atomic Weights of 

 other Simple Bodies/ 



By Henry Wilde, D.Sc, D.C.L., F.R.S. 



[Received May 22nd ^ irjij.) 



The recent determination of the atomic weight of tellurium 

 by AI. R. Metzner (Comptes Rendus, 13th June, i8q8) affords 

 me the opportunity of again directing the attention of savants 

 to the present anomalous condition of theoretical chemistry, and 

 to the obstacles that stand in the way of its future progress. 



The experiments made by M. Metzner show for tellurium 

 an atomic weight equal to 127.9 as the mean of one series, and 

 128.01 for the second scries. These results indicate a nearer 

 approach to the theoretical number 128, adopted by Dumas and 

 other chemists, than any previously recorded. 



The classical memoir of Dumas^ upon the cqun'alents of 

 simple bodies embodied all our real knowledge of the numerical 

 relations among the atomic weights until the publication of my 

 own memoir on the origin of elementary substances, "" wherein 

 the triads and other multiple relations of the atomic weights 

 revealed by the illustrious Dumas were greatly extended. I 

 also found that the common numerical difference between the 

 atomic weights of the oxygen series and the alkaline-earth 

 metals observed by Dumas was exactly paralleled by a common 

 difference in the atomic weights of the halogens and alkaline 

 metals of half the amount shown in the series of oxygen and 

 alkaline -earth metals. This new relation only became manifest 

 after the work of Dumas by the discovery of rubidium and 

 caesium, and by the adoption of the atomic weights of Canniz- 

 zaro. 



The absolute ]:)arallelisni of the positive and negative series 

 of elements Hn and H2n, as seen in my table (Comptes Rendus, 

 8th November, 1897), in their numerical, chemical and physical 

 relations, leaves no doubt that, for these four natural and best 

 known series, the multiple projiortions of their atomic weights 

 represent the truth of nature. The small differences observable 

 between the experimental and a few of the theoretical atomic 

 weights, when distributed among the twenty-four numbers com- 



1. Comptes Rendus De L'Academie Des Sciences, i8q8, tome 2. 



2. Comptes Rendus, tome XLV., p. 70Q, XLVL, p. 051, XLVII., p. 

 1,1126. 



3. Manchester Memoirs, 187S, 1S86, 1894. 



June iSth^ J 9 ^7- 



