The Primary Planets. 



293 



TABLE of the densities of the sun and of the 

 primary planets, compared with that of the 

 earth. 



Since the magnitude of the planets, and also 

 their densities, are known relative to the earth, 

 it is easy to know their solidity, by multiplying 

 these two quantities the one by, the other, re- 

 lative to that of the earth, which is taken for 

 unity. 



