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TEE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



to our earth a, reason- life (if we may so speak) 

 which, compared with the full life of the earth, is 

 but as a second compared with centuries. So far 

 as the existence of beings capable of thought and 

 reflection is concerned, our theory assuredly holds. 

 It is on a priori grounds utterly unlikely that any 

 one of the orbs we can actually observe is in- 

 habited by creatures like ourselves in those cir- 

 cumstances which dit-t'mguish us from the brutes 

 and from savages. 



So far as observation extends, in the case of 

 Mars, it seems altogether unlikely that the pres- 

 ent era of his existence corresponds with that 

 very brief period during which reasoning creat- 

 ures inhabit a planet. Supposing we have 

 rightly taken 200,000 years for the duration of 

 that period in our earth's case — and it seems 

 far more likely that the estimate errs in excess 

 than in defect — the duration of the correspond- 

 ing period in the case of Mars would prob- 

 ably be about 70,000 years. Mars would prob- 

 ably have entered on that stage of his existence 

 millions of years ago ; but, supposing for a mo- 

 ment that he reached it at about the same time 

 as our earth, or, according to our estimate, a 

 hundred thousand years ago, then the period 

 would have been completed about 30,000 years 

 ago. The appearance of the planet implies a 

 much later stage, however, of planetary exist- 

 ence. The seas of Mars present all the appear- 

 ance of exhaustion during millions of years, in 

 the course of which their waters have nourished 

 the surface of the planet with rain. The water 

 thus raised from the Martian oceans has no doubt 

 been always restored to them in large part, either 

 falling directly on the water-surface in rain, or 

 being gathered by streams and rivulets and rivers 

 on the land-surface, to be discharged by the river- 

 mouths into the seas. But a portion has always 

 been retained by the land, soaking slowly and 

 steadily into the interior of the planet. This 

 portion has doubtless been exceedingly small 

 each year, but during the long ages which have 

 elapsed since first the seas of Mars had separate 

 existence, the total amount thus drained off must 

 have been enormous. We see the effect in the 

 relatively small area of the Martian seas. They 

 cover barely half of the planet, while terrestrial 

 seas occupy nearly three-fourths of the surface 

 of our globe. They have the shape also which 

 our seas would have, if somewhat more than two- 

 thirds of the water were dried up. The variety 

 of tiut which they present shows that but few of 

 those seas are deep, for few of their are dark. 

 Many are so light as to suggest the idea that a 



large part of the area shown in the charts as 

 aqueous consists in reality of land and water so 

 broken up into small islands, lakes, straits, isth- 

 muses, and the rest, that the telescope cannot 

 distinguish the details. Again, the unchanging 

 color of the land-regions implies that they are 

 naked and sterile. Unless we adopt the theory 

 that not only is the vegetation of Mars rubescent, 

 but that all the principal glories of the Martian 

 forests are ever-reds, and the Martian fields 

 covered with herbage of unchanging ruddiness, 

 we must accept the conclusion that the land-sur- 

 face is an arid desert. This evidence alone is 

 almost strong enough to assure us that none but 

 the lowest forms of life — animal and vegetable — 

 exist on Mars at present. The evidence against 

 the fitness of Mars to support the higher forma 

 of life seems overwhelmingly strong. 



But, after all, why should a conclusion such 

 as this dishearten the student of other worlds 

 than ours ? Whether it relates to a planet here 

 and there, to Mars or Mercury, or the moon, be- 

 cause of their decrepitude, or to Jupiter and Sat- 

 urn because they are as yet too young, or whether 

 it is extended according to the laws of probability 

 to the universe of planets, does it not accord with 

 what we know of our own earth ? We do not 

 mean merely that our earth as a planet was once 

 unfit, and will one day become again unfit, to 

 support life ; but that even during the present 

 life-supporting era of its existence we do not find 

 all regions of the earth at all times fit to support 

 life ; nor do we find all races existing simultane- 

 ously. As various races begin, develop, and die 

 out, as various regions are at one time sterile, at 

 another clothed with life, so among the orbs in- 

 habiting space, now one set of races may exist 

 and anon an entirely different set, the series of 

 planets which during one era are the abode of 

 life beins; the nascent worlds of a former, the 

 dead worlds of a later era. A modern believer 

 in the universality of life says : " On those 

 worlds, as on ours, there are cities passing 

 through all the stages of glory and of power ; 

 there also, as here, there are cities like Rome, 

 and Paris, and London, altars and thrones, tem- 

 ples and palaces, wealth and misery, splendors 

 and ruins. And, perchance, from the venerable 

 ruins of an ancient capital two lovers at this mo- 

 ment on the planet Mars may be gazing on the 

 traces of the grandeur and of the decay of em- 

 pires, and feeling that amid all the metamor- 

 phoses of time and space, life, eternally young, 

 pervades the universe, reigning forever over all 

 the worlds, and. pouring forth endless youth in 



