338 HUMBOLDT'S COSMOS : 



changes in the Sun ; and can as little explain that singular 

 phenomenon of periods of temporary darkness or obscura- 

 tion, independent of solar eclipse, of which we have authentic 

 notices from various ages and parts of the world. Upon the 

 latter fact, however, we do not dwell in the way of analogy, 

 as it may more probably be due to atmospheric or meteoro- 

 logical causes than to actual changes in the Sun itself, 

 or possibly to the passing intervention of clouds of meteoric 

 matter between the Sun and the earth, during some part 

 of the annual revolution of the latter. 



We must not omit to notice here the fact, that several of the 

 more conspicuous fixed stars Sirius notably among the rest 

 exhibit dark lines in their spectra, permanently the same 

 for each ; and strictly analogous to those of the Sun, though 

 differing in distribution. There is a deep interest in this 

 phenomenon. It brings into direct association some of the 

 great physical laws and powers which act in our own system, 

 with those of worlds infinitely remote. We may not venture 

 to infer any such identity b/ matter^ as the spectrum analysis 

 has made known to us in the Sun. But that the material of 

 these worlds is analogous in kind., this principle of research 

 fully justifies us in believing. 



Seductive as are these speculations, we must hurry on to 

 other topics not less so. The next in order however that 

 of the Double and Multiple Stars is fast passing from the 

 region of speculation into that of exact science ; and the great 

 law of gravitation is becoming to our knowledge absolutely 

 coextensive with the existence of matter in motion, at what- 

 soever distance in space. That mere points of light many 

 of them only visible by the telescope, or from their vast 

 distance seem as single though really including two or 

 more stars should be made to yield the same conclusions 

 as the planets and satellites of our own system, is a marvel- 

 lous instance of human prowess; and scarcely credible to 



