36 THE CHEMISTRY OF THE PRIMEVAL EARTH. [IV. 



Huggins. We see, by its aid, mattter in all its stages, and 

 trace the process of condensation and the formation of worlds. 

 It is long since Herschel, the first of his illustrious name, con- 

 ceived the nebulae, which his telescope could not resolve, to be 

 the uncondensed matter from which worlds are made. Sub- 

 sequent astronomers, with more powerful glasses, were able to 

 show that many of these nebula are really groups of stars, and 

 thus a doubt was thrown over the existence of nebulous lumi- 

 nous matter in space ; but the spectroscope has now placed 

 the matter beyond doubt. By its aid, we find in the heavens, 

 planets, bodies like our earth, shining only by reflected light ; 

 suns, self-luminous, radiating light from solid matter; and, 

 moreover, true nebulas, or masses of luminous gaseous matter. 

 These three forms represent three distinct phases in the con- 

 densation of the primeval matter from which our own and 

 other planetary systems have been formed. 



This nebulous matter is conceived to be so intensely heated 

 as to be in the state of true gas or vapor, and, for this reason, 

 feebly luminous when compared with the sun. It would be 

 out of place, on the present occasion, to discuss the detailed re- 

 sults of spectroscopic investigation, or the beautiful and ingen- 

 ious methods by which modern science has shown the existence 

 in the sun, and in many other luminous bodies in space, of the 

 same chemical elements that are met with in our earth, and 

 even in our own bodies. 



Calculations based on the amount of light and heat radiated 

 from the sun show that the temperature which reigns at its sur- 

 face is so great that we can hardly form an adequate idea of 

 it. Of the chemical relations of such intensely heated matter, 

 modern chemistry has made known to us some curious facts, 

 which help to throw light on the constitution and luminosity 

 of the sun. Heat, under ordinary conditions, is favorable to 

 chemical combination, but a higher temperature reverses all 

 affinities. Thus, the so-called noble metals, gold, silver, mer- 

 cury, etc., unite with oxygen and other elements; but these 

 compounds are decomposed by heat, and the pure metals are 

 regenerated. A similar reaction was many years since shown 



