428 THE BEAUTIES OE NATURE chap. 



lapse of time is a grander element in Astron- 

 omy even than in Geology, and dates back 

 long before Geology begins. We must figure 

 to ourselves a time when the solid matter 

 which now composes our Earth was part of 

 a continuous and intensely heated gaseous 

 body, which extended from the centre of the 

 Sun to beyond the orbit of Neptune, and 

 had, therefore, a diameter of more than 

 6,000,000,000 miles. 



As this slowly contracted, Neptune was 

 detached, first perhaps as a ring, and then as a 

 spherical body. Ages after this Uranus broke 

 away. 



Then after another incalculable period 

 Saturn followed suit, and here the tendencies , 

 to coherence and disruption were so evenly 

 balanced that to this day a portion circulates 

 as rings round the main body instead of being 

 broken up into satellites. Again after succes- 

 sive intervals Jupiter, Mars, the Asteroids, 

 the Earth, Venus, and Mercury all passed 

 through the same marvellous phases. The 

 time which these changes would have re- 

 quired must have been incalculable, and they 



