14 CELESTIAL AND TERRESTRIAL ANALOGIES. 



tions confirm a belief that all the planetary 

 worlds are adapted for abodes of intelligences, 

 and for promoting the happiness of sentient 

 beings. 



The original placing of the revolving worlds 

 in the heavens, being ascribed by Mechanical 

 Philosophy to an immaterial First Cause, is be- 

 yond the reach of physical investigation; which 

 therefore begins with the manifest facts at- 

 tending their actual existence and movements. 

 It is not necessary for an engineer to know who 

 invented the steam-engine, or how and when it 

 was originally made, before he can proceed to 

 study the general principles that govern its op- 

 eration. Its actual construction and functions 

 reveal the science and ability of the maker, and 

 his purpose. 



The mechanism of the solar system being far 

 beyond the possibility of immediate examination, 

 Sir John Herschel points out to students " the 

 surest guide for direction, by reasoning from an- 

 alogy of celestial to terrestrial mechanics ; " both 

 being alike governed by universal laws. Professor 

 Proctor says : " Terrestrial analogies afford a very 

 sure guide in the midst of the many perplexities, 

 which the study of the worlds around us presents 

 to our contemplation." After recognizing the law 

 that matter put in motion cannot stop itself, the 

 student realizes that the vast masses of the re- 

 volving planets serve as balance-wheels to retain 



