THE BORDERLAND OF SCIENCE. 



volume of Uranus exceeds the combined volume of all 

 the inner planets upwards of thirty times. I might 

 adduce many other illustrations of the complete 

 dissimilarity between the inner and outer families of 

 planets ; but what has been already stated will suffice 

 for our present purpose. It will be evident that in 

 considering the members of one or other family, we 

 must be prepared to meet with relations which differ 

 not merely in degree, but in kind. We may thus, at 

 the outset, dismiss from our thoughts the idea that the 

 planet Jupiter is necessarily to be regarded as an 

 inhabited world merely because the only planet we are 

 actually acquainted with is inhabited. The latter 

 circumstance may be an excellent reason for regarding 

 Mars or Venus as the abode of life ; but the analogy 

 can no more be extended to Jupiter than to the fixed 

 stars, which certainly are not inhabited worlds. We 

 must, in fact, consider the physical habitudes of Jupiter 

 independently of all conceptions based upon terrestrial 

 analogies. Studied thus, he will be found, as we 

 conceive, to hold a position in the scheme of creation 

 differing considerably from that which has been assigned 

 to him, until of late, in treatises on astronomy. 



It is necessary briefly to state the dimensions, mass, 

 and general characteristics of the planet, before pro- 

 ceeding to discuss its probable physical condition. 



Jupiter has a diameter exceeding the earth's rather 

 more than ten times, and a volume exceeding hers 

 1,230 times. It is not far from tiie truth to say that 

 Jupiter's dimensions exceed the earth's in very nearly 



