PLURALITY OF WORLDS. 29 



special adaptations, where the prevision and power to 

 adapt are so manifest to our reason. The various cli- 

 mates and conditions of the earth itself interpret to us 

 in their effects endless possibilities of existence in other 

 worlds than our own. 



The arguments which serve to this conclusion re- 

 garding the planets do not apply to that mighty central 

 globe, ' lo ministro maggior della natura,' which fulfils 

 the great function of keeping all in their orbits and 

 giving light and heat to all. We cannot prove or 

 presume anything beyond this, nor indeed conceive a 

 habitable world in this great focus of illimitable forces. 

 But the argument again opens upon us, when proceed- 

 ing further into the depths of space, and discovering, 

 among what we call the fixed stars, numerous systems 

 of suns and satellites, having kindred with our own in 

 the phenomena of gravitation and revolution. Tele- 

 scopic vision tells us distinctly of these wonderful and 

 complex relations in what to the naked eye are but 

 the single and immovable stars of heaven. The light 

 which solely gives us knowledge of their existence, 

 though taking years for its transit through intervening 

 space, reaches the earth with properties essentially the 

 same as the beam coming direct from the sun not, 

 indeed, affording sensible heat, save in a few instances, 

 to the keen scrutiny of modern research, but yielding 

 photographs by its chemical action, and certain of 

 those spectrum lines, which tell of material elements in 

 those remote worlds analogous to, in fact identical 

 with, some of the components of our own globe. This 

 last wonderful attainment of human research is prolific 



