!go PIONEERS OF EVOLUTION. 



of the metals and metalloids (or non-metallic ele- 

 mentary substances, to which class both oxygen and 

 nitrogen belong), or their compounds, is examined 

 with the spectroscope, the spectra of the metalloids 

 always yield before that of the metals. Hence the 

 absence of the lines of oxygen and other metalloids, 

 carbon and silicon excepted, among the vast crowd 

 of lines in the solar spectrum. Then, too, in extreme 

 states of rarefaction of the sun's absorbing layer, 

 the absorption of the oxygen is too small to be sen- 

 sible to us. 



" While the genesis of the Solar System, and of 

 countless other systems like it, is thus rendered com- 

 prehensible, the ultimate mystery continues as great 

 as ever. The problem of existence is not solved: 

 it is simply removed further back. The Nebular 

 Hypothesis throws no light on the origin of diffused 

 matter; and diffused matter as much needs account- 

 ing for as concrete matter. The genesis of an atom 

 is not easier to conceive than the genesis of a planet. 

 Nay, indeed, so far from making the universe a less 

 mystery than before, it makes it a greater mystery. 

 Creation by manufacture is a much lower thing than 

 creation by evolution. A man can put together a 

 machine; but he cannot make a machine develop 

 itself. The ingenious artisan, able as some have 

 been so far to imitate vitality as to produce a me- 

 chanical pianoforte player, may in some sort con- 

 ceive how, by greater skill, a complete man might 

 be artificially produced ; but he .is unable to conceive 



