THE STELLAR UNIVERSE. 357 



THE STELLAR UNIVERSE. 



(FIRST LECTURE.) 



THE distances, probable magnitudes, splendor, and pbysical character of 

 such of the fixed stars as are visible without telescopic aid, have been already 

 explained.* The range of this survey was shown to be circumscribed by a 

 sphere, of which the solar system is the centre, and of which the radius is a 

 length which light, moving at the rate of two hundred thousand miles per sec- 

 ond, would take ten years to traverse. Such is the limit which has been im- 

 posed on the natural power of the eye. Beyond this distance the creation 

 was concealed from human vision until the invention and improvement of the 

 telescope. That instrument has augmented the range of observation and dis- 

 covery in a very high proportion, and has opened to our examination realms > 

 of space occupied by innumerable systems, stretching to distances which may 

 be pronounced to be infinite, in the only sense in which that negative term 

 can properly be used. 



But besides bringing within the range of the senses objects placed beyond 

 the limits of that vast sphere, the telescope has also greatly multiplied the 

 number of visible objects within it, by enabling us to see those whose minute- 

 ness would have otherwise rendered them invisible. Among those stars 

 which are visible to the naked eye, there are many thousands respecting which 

 the telescope has detected circumstances of the highest physical interest, by 

 which they have become more closely allied with our own system, and by 

 which it is demonstrated that the same material laws which coerce the planets, 

 and give stability, uniformity, and harmony, to their motions, are also in opera- 

 tion in those remote regions of the universe. We shall first notice some of 

 the most remarkable discoveries respecting individuals among the visible stars, 

 and shall afterward explain those which relate to the arrangement of the col- 

 lective mass of stars which compose the visible firmament, and the result of 

 those researches which the telescope has enabled astronomers to make in more 

 remote regions of the universe. 



* 8ee discourse on " The Visible Stars," VoL I, p. 583. 



