DRIFTING UGHT.WAVES. 105 



of spectroscopy. A century or so hence astronomers will 

 smile (though not disdainfully) at these feeble efforts, much 

 as we smile now in contemplating the puny telescopes 

 mth which Galileo and his contemporaries studied the 

 star-depths. And we may well believe that largely as the 

 knowledge gained by telescopists in our own time surpasses 

 that which Galileo obtained, so will spectroscopists a few 

 generations hence have gained a far wider and deeper 

 isight into the constitution and movements of the stellar 

 universe than the spectroscopists of our own day dare even 

 hope to attain. 



I venture confidently to predict that, in that day, as- 

 tronomers will recognize in the universe of stars a variety 

 of structure, a complexity of arrangement, an abundance 

 of every form of cosmical vitality, such as I have been led 

 by other considerations to suggest, not the mere cloven 

 lamina of uniformly scattered stars more or less resembling 

 our sun, and all in nearly the same stage of cosmical de- 

 velopment, which the books of astronomy not many years 

 since agreed in describing. The history of astronomical pro- 

 gress does not render it probable that the reasoning already 

 advanced, though in reality demonstrative, will convince the 

 generality of science students until direct and easily under- 

 stood observations have shown the real nature of the con- 

 stitution of that part of the universe over which astronomical 

 survey extends. But the evidence already obtained, though 

 its thorough analysis may be "caviare to the general," suffices 

 to show the real nature of the relations which one day will 

 come within the direct scope of astronomical observatioa 



