36 IN STARRY REALMS. 



to pass into the decrepit state when its powers of radiat- 

 ing heat and light have become greatly impaired before it 

 passes finally into the death-like condition in which it will 

 have no longer any stores of light and heat to dispense. 

 When we look at a forest we see there are a multitude of 

 trees in every stage of development. There are some 

 which are still only young seedlings ; there are others 

 which are vigorous saplings ; there are a few splendid 

 trees of ample dimensions, and there are others whose 

 mighty trunks show symptoms of decay, while some have 

 already succumbed and are found prostrate and lifeless. 

 These several stages can be witnessed in a glance through 

 a forest glade. In a similar way when we look up at the 

 starry heavens we see a vast multitude of suns in every 

 phase of development ; there are some still in the entirely 

 gaseous state, they merely appear as stains of light on the 

 sky ; they are what we call the nebulae. There are others 

 again in which the gradual condensation of the gas has so 

 far advanced that a central and brighter part can be dis- 

 tinguished. In other nebulae this brighter part has 

 become starlike, and in yet others the transformation has 

 proceeded so far that the nebula seems merely a glow of 

 gaseous atmosphere around a brilliant star. In continuing 

 our search we find others in which the nebula has entirely 

 vanished, while the brilliant star which remains is a 

 striking illustration of the doctrine that the intense fer- 

 vour of sunlike bodies is due to their contraction from an 

 original gaseous form. 



Thus we find the stars furnish us with many excellent 

 illustrations of epochs in the sun's history up to the 

 present time in which the sun has assumed the definite 



