132 KANSAS CITY REVIEW OF SCIENCE. 



Mercury, in view of Professor Langley's determination of the astonishing rate of 

 radiation in a thin atmosphere. At the upper Hmit of an atmosphere sufficiently 

 dense to support aqueous vapor, it seems not irrational to assume that escape of 

 heat would be rapid enough to condense water even in the fierce solar heat experi- 

 enced at Mercury's distance from the Sun, So far as the existence of a stratum 

 of clouds is possible, this would, of course, serve as a screen for the surface of 

 the planet, so that comparatively little of the Sun's direct radiation would inter- 

 fere with habitability. In this view there seems no great improbability that both 

 these planets are inhabited by intelligences organized somewhat like ourselves. 

 The amount of water belonging to these planets being in less proportion than on 

 the earth, the processes of evaporation and precipitation must keep it in active 

 circulation. No very considerable bodies of water can be supposed to exist, and 

 a large proportion of the entire surface must be accessible to occupation and cul- 

 tivation. The final absorption of the water will, therefore, occur at a relatively 

 early epoch, when, of course, habitability must end. 



Thus, the first thought of these sister worlds suggests that they may be the 

 homes of beings kindred to ourselves. Then the knowledge of the intensity of 

 the solar radiations on their surfaces seems to preclude the belief in their habita- 

 bility. But finally, a discovery of natural means for the alleviation of excessive 

 heat leaves us with the conviction that after all we may have neighbors on the 

 contiguous planetary territory. As to their organization, while it is profoundly 

 true that under circumstances extremely diverse from those under which we live, 

 extremely diverse organizations must be conceived both possible and probable ; 

 yet where the divergence is no greater than on the interior planets, all the funda- 

 'mental functions and processes may be conceived analogous to our own. There 

 is so widespread uniformity in the nature and action of physical forces that we may 

 suspect the same in regard to organic structures and activities. As organization 

 in its forms and functions is conditioned by the properties of matter and the laws 

 of energy, and these conditions are widely pervasive throughout our system, we 

 have good ground for believing that plans of organization and modes of activity 

 are fundamentally analogous under all planetary conditions not more diverse than 

 we conceive those of the earth and the interior planets to be. In fact, there exist 

 contrasts of condition upon the earth nearly as wide as the contrasts between the 

 earth and Venus. In all these contrasted situations nature employs the same 

 fundamental plans of organization and functioning. 



On the whole, as intelligence must be revealed in the cosmic organization of 

 Mercury and Venus, there are presumably intelligent beings in correlation with 

 the intelligible world ; and as the conditions of corporeality are so far analogous 

 to those on the earth, we may reasonably conceive organic intelligences on these 

 planets who have power of locomotion by muscles and bones ; who eat and re- 

 spire; who suffer and enjoy; who cognize light and heat and sound; who ob- 

 S3rve and reflect, imagine and aspire ; and, while ignorant, probably, of many or 

 most of our arts, have invented many others of which we never dreamed, and 

 achieve accomplishments which would be miracles to us. 



