488 Scientific Intelligence. 



produced bands of absorption; didymium, for example, being 

 capable of resolution into at least nine separate components. In 

 carrying on their work these chemists have adopted Crookes's 

 suggestion and have endeavored to select minerals in which the 

 particular element desired has been accumulated by nature's 

 processes. Thus, for example, the fergusonite from Arendal 

 shows six of the bands of holmium, that from Ytterby four and 

 that from Hittero only three. This mineral from Ytterby, more- 

 over, contains the element provisionally named Xor; but this 

 element is absent in the mineral from the other two localities. 

 The extraordinary complexity of some of these minerals is shown 

 by the fact that after removing the ordinary metals, euxenite 

 contains the rare elments Ce, La, Di, Sm, Yt, Er, Tr, Ho, Tm, 

 Th, De, Sc, Dy, Be, Nb and Ta. 



Passing to spectra produced by the phosphorescence of molec- 

 ular bombardment, the author takes up first the yttrium group. 

 Yttrium itself he concludes may be split up certainly into five 

 and probably into six constituents. In one plate its complete 

 phosphorescence spectrum is. shown and in a second one below it 

 the simple spectra of the separate components into which yttria 

 can be separated by fractionation. As the result of many years 

 work and of several thousand fractionations of old yttria, the 

 author exhibited a series of nineteen phosphorescence spectra, 

 the center on'e being approximately that of the crude earth, and 

 those above and below representing the shading off in one direc- 

 tion or the other of the lines given by the several fractions. 

 *' To make the diagram more accurately represent what actually 

 occurs in the laboratory it would be necessary," he tells us, " to 

 place between each of these nineteen spectra about 1000 inter- 

 mediate spectra." " A study of this diagram," he says, " will, I 

 think, convince any impartial observer that the lessons it conveys 

 fully bear out my contention that samarium, gadolinium, mosan- 

 drum and yttrium are not actual chemical elements but are com- 

 pounded of certain simpler bodies which may conveniently be 

 called meta-elements." Hence he concludes that our notions of a 

 chemical element must be enlarged; "hitherto the elemental 

 molecule has been regarded as an aggregate of two or more 

 atoms and no account has been taken of the manner in which 

 these atoms have been agglomerated. The structure of a chem- 

 ical element is certainly more complicated than has hitherto been 

 supposed. We may reasonably suspect that between the mole- 

 cules we are accustomed to deal with in chemical reactions, and 

 the component or ultimate atoms, there intervene sub-molecules, 

 sub-aggregates of atoms or meta-elements, differing from each 

 other according to the position they occupy in the very complex 

 structure called ' old yttrium.' " This " assumption of compound 

 molecules will perhaps account for the facts and thus legitimate 

 itself as a good working hypothesis, whilst it does not seem so 

 bold an alternative as the assumption of eight or nine new 

 elements." 



