204 ASTRONOMr. 



hand. In the planetary revolutions there are the 

 same two forces ; the only difference being, that the 

 attraction of the sun upon the planets is a substitute 

 for the string. 



B. From how simple powers are the most stupen- 

 dous effects produced in nature ! What an amazing 

 conception, that the simplest toy of a child compre- 

 hends the whole mechanism of worlds all in rapid 

 motion, yet calm, regular and harmonious. 



T. But this admirable mechanism is not to be un- 

 derstood from so simple an illustration as this, except 

 in some very general points of view. There are im- 

 portant respects in which it fails to convey any ade- 

 quate idea of the wisdom exhibited in the planetary 

 frame. The earth and planets are held in their orbits 

 by the attraction of the Sun. This is true. But the 

 attraction is not peculiar to the Sun. It is an attrac- 

 tion which all bodies exert upon one another in pro- 

 portion to their quantities of matter. The sun being 

 by far the largest body in the system, possesses the most 

 of this attractive power, on account of his superior 

 magnitude. And all the planets exert the same kind 

 of attraction upon one another, though in a less de- 

 gree. If we were to fasten a number of loadstones 

 to separate strings, and whirl them around another 

 larger loadstone in our hand, this would resemble the 

 sun and planets ; — but then while the loadstones re- 

 volved they would be liable, from their natural attrac- 

 tion, to rush together and form one solid mass. What 

 is to prevent the planets from doing the same, and 

 involving the whole system in destruction ? 



