HABITABILITY OF OTHER WORLDS. 131 



high intelligence might be enframed in a gill-bearing embodiment ; and resources 

 and stimuli for intellectual activity might be discovered in the bottom of the 

 ocean, or in the infinitesimal world which fills a slimy pool, or " swarms upon 

 the thickly peopled air." Nor is incorporated rational existence conditioned on 

 warm blood, nor on any temperature which does not change the forms of matter 

 of which the organism may be composed. There may be intelligences corporeal- 

 ized after some concept not involving the processes of ingestion, assimilation and 

 reproduction. Such bodies would not require daily food and warmth. They 

 might be lost in the abysses of the ocean, or laid up on a stormy cliff through the 

 tempests of an arctic winter, or plunged in a volcano for a hundred years, and 

 yet retain consciousness and thought. It is conceivable. Why might not psy- 

 chic natures be enshrined in indestructible flint and platinum ? These substances 

 are no further from the nature of intelligence than carbon, hydrogen, oxygen 

 and lime. But, not to carry the thought to such an extreme, might not high 

 intelligence be embodied in frames as indifferent to external conditions as the 

 sage of the western plains or the lichens of Labrador — the rotifers which remain 

 dried for years or the bacteria which pass living through boiling water. Again, 

 there is no reason why a given amount of light should accompany intelligent 

 organization. Many animals, not among the least intelligent, find the night their 

 appropriate period of activity. Some exist and thrive in rayless caverns and 

 ocean depths. On a planet dimly lighted, like Neptune, men might be organized 

 with pupils as large as silver dollars, or even as large as dinner plates. Vision 

 might be as distinct on Neptune as on the earth. As to warmth, a blanket of 

 vapors may keep it in and accumulate it to the requisite extent. And in that 

 distant time when the Sun shall become planetary, large-orbed men may move 

 about in starlight over a surface sufficiently warmed by internal heat, and forms 

 of vegetation may flourish and supply food for man and beast without the stimu- 

 lus of solar radiations. These suggestions are made simply to remind the reader 

 -how little can be argued respecting the necessary conditions of intelligent, organ- 

 ized existence, from the standard of corporeal existence found upon the earth. 

 Intelligence is, from its nature, as universal and as uniform as the laws of the 

 universe. Bodies are merely the local fitting of intelligence to particular modifi- 

 cations of universal matter and force. 



But let us consider how far other worlds are suited for habitations for beings 

 akin to ourselves. This is a question for scientific consideration. The answer to 

 the question, when asked with reference to each of our planets, is to be sought 

 in what has been already said concerning the physical conditions of the planets. 

 Mercury is not habitable for beings like ourselves. Proximity to the Sun results 

 in a destructive degree of heat, if it does not actually prevent all water from find- 

 ing a resting-place on the planet's surface. The Sun's apparent diameter from 

 Mercury is more than two and a half times as great as from the earth. 



In reference to Venus, and possibly also Mercury, we must bear in mind 

 that the relations of heat and water are such that water might exist as a dense 

 and permanent envelope of clouds. This seems the more probable, even for 



