142 INORGANIC EVOLUTION. [CHAP. 



Although this discussion of the distribution of different types of 

 stellar spectra indicates a collective tendency of some types, it proves 

 at the same time that the chemical substances represented in such 

 types are distinctly not limited to the regions in which they pre- 

 dominate. Thus we know of hydrogen in all stars except the carbon 

 stars ; although the stars showing strong indications of helium are most 

 numerous in and about the Milky Way, stars of this kind do appear 

 in other parts of space remote from the Milky Way, among them 

 being the bright stars Spica and 77 Ursse Majoris. Besides this direct 

 evidence of the wide diffusion of helium there is the indirect evidence 

 based upon the fact that helium is known to be present in the sun 

 although it is not represented among the Fraunhofer lines. By 

 analogy then we must allow that helium is also present in Arcturus 

 and the thousands of other stars which have spectra like the sun which 

 have no special connection with the Milky Way. Helium must, there- 

 fore, be practically like hydrogen, distributed in all directions as seen 

 from the sun. 



Another illustration of this general diffusion of a particular kind 

 of matter is afforded by carbon. In the hottest stars, stars like the 

 sun, and the coolest stars, we alike find indications of this substance, 

 so that a localisation of any particular type of star does not imply the 

 restriction of carbon to such localities. Again, if we take iron, we 

 find its indications, either as iron or proto-iron, through a great variety 

 of stellar types, while we may say that calcium and magnesium show 

 direct evidence of their presence in almost every star. 



Thus we are led to conclude that there is no localisation of the 

 chemical elements so far as direction in space is concerned. While the 

 discussion of proper motion indicates that particular types of stars 

 tend to congregate at distances peculiar to themselves, the condensa- 

 tion is by no means absolute. Some stars of each type have proper 

 motions widely different from the average. Hence at all distances 

 from us we find similar chemical types of stars and therefore evidence 

 of similar chemical substances. 



We have already seen that the chemistry is the same in all direc- 

 tions, so that, finally, we must grant that the chemistry of all parts of 

 space is the same. In other words the chemical parishes required by 

 the view that the stellar types represent different chemical conditions 

 as regards the presence or absence of certain substances do not exist. 

 In no direction from our system, in no shell surrounding it, is any 

 chemical element found which is not present in other directions and in 

 other shells. 



The major objection then against the stellar evidence in support 

 of the dissociation hypothesis, upon inquiry, vanishes into thin air. 



