‎"RYDBERG, J.R. (JOHANNES ROBERT).‎
‎Untersuchungen über das System der Grundstoffe.‎

‎Lund & Leipzig, Gleerup & Harrassowitz, 1913. 4to. In the original printed wrappers. With author's presentation inscription to top of front wrapper: ""Från vännen forf."" Fine and clean. 41 pp.‎

Reference : 52991

‎First appearance of Rydberg's important paper in which continued his revision of the periodic system. Here he ascribed two hypothetical new elements which he called nebulium and coronium and came up with the formula 2p*2 (p integer) which Sommerfeld called ""cabbalistic"" in his book ""Atombau und Spektrallinien"".‎