284 EIGHTEENTH CENTURY. ft. hi. 



of the most tremendous problems in the working of our 

 universe. Here we find Lagrange proving that the system 

 of our sun and planets is self-regulating, so that in spite of 

 all its infinite changes, there is no real irregularity or change- 

 ableness in its machinery, but all moves in one perfect and 

 constant round. Laplace shows the reason of those irregu- 

 larities which seemed to contradict Newton's law of gravita- 

 tion, and proves that they are all explained by that law, 

 thus completing the work of the great astronomer. Then 

 Herschel takes up the story, and after discovering a new 

 planet, he studies the cloudy nebulae, and points out the 

 probable formations of new suns going on now in far-distant 

 regions; he pictures our own sun rushing through space at 

 the rate of 150,000,000 miles a year, carrying with it our 

 earth and all the other planets ; and above all he traces 

 the law of gravitation into the distant star- world, and shows 

 it there holding suns together and causing them to revolve 

 round each other. And so, out into space as far as the 

 mind can reach, we find everlasting order reigning through 

 out the visible universe. 





List of Works consulted. — Herschel's 'Astronomy;' Arago, *Vie 

 et travaux de Herschel,' i{^43 ; Proctor's 'Essays on Astronomy,' 

 ' The Universe,' 'Other Worlds than Ours'; Grant's 'History of 

 Physical Astronomy ; ' Arago, ' Eloge of Laplace ; ' Airy's ' Astro- 

 nomy ; ' ' Encyclopaedia Britannica * — ' Astronomy ; ' ' Orbs of 

 Heaven,' Mitchell. 



