96 INORGANIC EVOLUTION. [CHAP. 



time ago when we imagined that the gas obtained from the mineral 

 cleveite, when exposed to the action of a high tension spark, was really 

 a single gas with six series. Very many arguments have been employed 

 to show that that view is probably not an accurate one ; so that some 

 are prepared to separate the cleveite gas at spark temperatures into two, 

 calling one helium and the other asterium. That brings these two con- 

 stituents of the cleveite gas, brought out by high temperatures, to the 

 same platform as hydrogen with the recent developments, lithium, 

 sodium, sulphur, &c. 



If we consider this extraordinary condition in the case of oxygen a 

 little further, we find that the six series only after all pick up the oxygen 

 hues seen at a low temperature, and that if we employ a high temperature 

 to observe the oxygen spectrum, that is to say, if we use an induction 

 coil, a jar and an air break, we find a very considerable number of lines 

 which have no connection whatever with any of the series so far made 







su 1 i 



*rS3 



&& 



Suki. 



E 



#IG. 34. Map showing series and residual lines in spectra of calcium and 



magnesium. 



out. And we are face to face with this very awkward fact, that in the 

 case of oxygen there are more lines which we cannot get into a series 

 than there are lines in the six series which we have attributed to that 

 chemical substance. Here, therefore, on the hypothesis that we are 

 dealing with the oxygen " atom" we begin certainly to get into diffi- 

 culties. The inquiry is not straightforward. 



The next point is, that in the case of other substances, we have no- 

 series, but only two subordinate ones. This happens in the 



