62 Kansas Academy of Science. 



a habitable globe to-day. Without its existence as a heat producer 

 in disturbing subterrranean tranquillity, the earth ere this would 

 have become a cold, solid, asymetrical, non-rotating spheroid. It 

 is impossible that a large composite body of fluid become solid 

 from loss of heat and retain symmetrical distribution of mass about 

 its center of figure. Some parts or segments of the same radial 

 distance from the center, and in the same plane parallel to the 

 equator, will cool sooner than the remaining segments similarly 

 situated, and from various causes, and asymmetry will follow. 

 With asymmetry and complete solidity rotation must cease, as in 

 the cases of Mercury, Venus, the moons, and the asteroids. Wher- 

 ever we find a planet with a moon, or with moons, we may infer a 

 rotation and a fluid interior, and with moonless planets the ab- 

 sence of both. 



