i WONDERS OF NATURE COMETS 273 



by itself, they argue, would be dissipated and would 

 have nothing to hold or to be held by. If it were 

 merely massed and not attached to a solid body, 

 the universe would assuredly long since have 

 scattered it in its impetuous whirl. 



II 



IN view of this inquiry it will be well to ask i 

 whether comets are wholly analogous to stars and 

 planets. They seem to have certain elements 

 in common with them for example, rising and 

 setting as well as their general form, although 

 comets are more scattered, and end in a longer 

 tail. They are alike, too, in their fiery bright 

 appearance. So, if all the stars are earthy bodies, 

 comets must share the same lot. But if the 2 

 stars are pure fire and nothing else, remaining 

 for six months at a time unbroken by the rapid 

 whirl of the universe, then comets, too, may 

 consist of some rarefied material, which is not 

 broken up by the constant revolution of the sky. 

 It will also tend to clear up this point if we 

 endeavour to ascertain whether the earth stands 

 still while the universe revolves round it, or 

 whether the converse is the truth, the universe 

 standing still while the earth revolves. There 

 have been persons who made bold to say that 

 it is we that all unwitting are borne round by 

 the frame of things, that risings and settings are 

 not produced by a movement of the heavens, but 

 that we ourselves rise and set. The subject well 3 

 deserves our study, if we are to know where we 

 really stand, whether the abode we have obtained 



T 



