8 THE HARMONIES OF NATURE. 



Before Bessel made the first successful attempt to determine 

 the distance of a fixed star, Sir John Herschel had already 

 taken the first steps towards the conquest of the sidereal heavens. 

 Through telescopes of an increasing range, he saw with their 

 growing power the number of the stars increase that presented 

 themselves before his field of vision, and thus gained a measure 

 for the form and the dimensions of the stellar system to which 

 our sun with all his satellites belongs. 



This amazing cluster of worlds this our ( world-island,' as 

 it has been appropriately called by Humboldt, consisting 

 of all the constellations seen with the naked eye, and of the 

 unnumbered stars that glimmer in the Milky Way is of a 

 lenticular, flattened, oblong, or elliptic form, and swims like 

 a prodigious archipelago in the unmeasured realms of space. 

 We know the immense distances that separate us from the 

 nearest fixed stars, and can thus form a faint conception of the 

 vast dimensions of a group composed (according to Herschel) of 

 at least twenty millions of self-luminous stars. It has been 

 calculated that a ray of light would require at least six thousand 

 years to measure it from end to end, and fourteen hundred 

 years to traverse it in its breadth. But even this amazing 

 group of stars, vast and colossal beyond the bounds of human 

 imagination, forms but a point in the universe, for on all sides 

 similar clusters are seen looming out of the depths of the skies at 

 distances to which that of Siriusfrom the earth dwindles down to 

 one of our terrestrial measures. Many of these clusters, which 

 are either entirely invisible to the naked eye, or appear only as 

 nebular spots on the dark background of the celestial vault, 

 require Lord Rosse's great telescope to be dissolved into their 

 component stars ; while others resist even this powerful test, 

 and continue to appear as specks of mere luminous matter. 



Hitherto it was supposed that the immensity of their 

 distances alone prevented them from being dissolved ; but the 

 true nature of some of them at least has been fully established 

 by recent investigations, which, by extending Bunsen's and 

 Kirchhof 's solar discoveries into the world of the fixed stars, have 

 not only been able to prove that the glowing atmosphere of 

 Aldebaran, for instance, contains quicksilver, and that of Sirius 

 antimony, but that many of the nebulae are in reality but 

 immense gaseous bodies, which we may suppose to be new 



