so-called Meta- Elements. Ill 



spark-spectrum of the original yttria : he then brings before 

 them that of the earth G,,. Are these spectra different ? No, 

 absolutely and exactly the same in every particular. He then 

 brings before them that of the earth G St Surely this will be 

 different to a certain degree, even though it be slight. No, 

 it is exactly the same in every respect with the spectra of 

 both the original yttria and of the earth G,,. 



How, then, does Crookes explain this ? He offers the 

 following alternative suggestions : — 



(1) " Elements are not as simple as we suppose. Our 

 notions of a chemical element have expanded. Hitherto 

 the molecule has been regarded as an aggregate of two or 

 more atoms, and no account has been taken of the architec- 

 tural design on which these atoms have been joined. We 

 may consider that the structure of a chemical element is more 

 complicated than has hitherto been supposed. Between the 

 molecules we are accustomed to deal with in chemical reac- 

 tions and ultimate atoms as first created come smaller mole- 

 cules or aggregates of physical atoms : these submolecules differ 

 one from the other according to the position they occupied in 

 the yttrium edifice. We may consider them similar to the 

 carbon atoms in the benzene ring which have the impress of 

 their position 1, 2, 3, 4, 5 stamped on them.'"' That is to 

 say, these fractionated earths are to be considered as isomor- 

 phous bodies composed of the same atoms arranged in different 

 ways within the molecule. Why, then, call them meta- 

 elements, thereby implying that they contain totally different 

 forms of matter, when in reality they all contain the same ? 



(2) u These nine earths are chemical elements differing in 

 basic powers and several other chemical and physical pro- 

 perties, but not sufficiently to enable us to effect any but a 

 partial separation. Thus G$, for instance, gives a certain 

 spectrum under the influence of the electric spark : the other 

 earths, G e , G,,, &c, are contaminated with a certain quantity 

 of this G$ ; and so the spectra of these other earths, G e , G,,, 

 &c, is that of Q s and G$ only, they themselves presumably 

 not having any spectra at all, or what they do have is masked 

 by the greater intensity of that of G %" 



Can this suggestion hold? Is it probable that not the 

 slightest trace of any other lines but those due to an impurity 

 would be observed in the spectrum of a body containing only 

 a small quantity of this other body as an impurity, and not a 

 single one would be observed due to the earth under exami- 

 nation ? Surely not. 



Again we ask, Do the atomic weights of these fractionated 

 earths differ ? Again we must answer in the negative. No 



K2 



