THE PLAXET OF WAR. 



3G5 



able elevation. Then we have the presence of 

 water, and of a stable atmosphere in which the 

 vapor of water rises. It seems no daring as- 

 sumption to suppose that this air is constituted 

 much like our own air. In the first place, if the 

 air were formed of other gases, the spectroscope 

 would probably reveal their existence, which has 

 not happened ; and, secondly, with the evidence we 

 have of a general similarity of structure and 

 origin, an atmosphere of nitrogen and oxygen 

 would naturally be formed while the planet was 

 developing to its present condition, and would 

 remain after other constituents of the planet's 

 primeval atmosphere had been removed. For a 

 similar reason we may safely infer that the green- 

 ish hue of the water implies the presence of the 

 same substances, though not perhaps similarly 

 proportioned, which are carried in suspension in 

 our oceans, and give to them their green, green- 

 blue, and blue tints. 



It is important to notice these general resem- 

 blances, either demonstrated or safely to be in- 

 ferred. We no longer propose to deduce from 

 them the conclusion that the planet's present 

 condition is like that of our own earth. We 

 might, indeed, dwell on some considerations 

 which naturally suggest themselves here. We 

 might see in imagination the waves of those dis- 

 tant seas beating upon the long shore-lines, and 

 hear " the scream of a maddened beach dragged 

 down by the wave." We can imagine the slow 

 progress of the Martian day — the mists of morn- 

 ing gradually clearing away as the sun rises ; the 

 winds raised by the mid-day heat, zephyrs mur- 

 muring among the distant hills or blasts roaring 

 loudly over desolate rock-bound seas ; the gath- 

 ering of clouds toward eventide, though probably 

 to pass from the skies at night (because con- 

 densed by cold), leaving the same constellations 

 we see to shine with greater splendor through a 

 rarer atmosphere. We can imagine all this, be- 

 cause we know from what the telescope has re- 

 vealed that such must be the changes of the Mar- 

 tian day. We see in the telescope the long, 

 white shore-lines, the clearing mists of morning, 

 the gathering mists of night, and we know that 

 there must be air-currents in an atmosphere un- 

 dergoing such changes. There must be rain, and 

 snow, and hail, and electrical disturbances — 

 thunder and lightning at times — besides torna- 

 does and hurricanes, blowing probably more fierce- 

 ly than our own, though their destructive effects 

 must be less because of the greater tenuity of 

 the Martian air. 



But while we recognize in imagination the 



progress of such events as these, we must not 

 forget that for countless ages in the past mighty 

 processes of disturbance and continuous pro- 

 cesses of steady change took place in our earth 

 when as yet there was no life, nor that probably 

 life will have ceased to exist on this earth mill- 

 ions of years before the land, and sea, and air, 

 will cease to be the scene of Nature's active but 

 unconscious workings. We cannot deduce from 

 the mere fact that, if living creatures existed on 

 Mars they would witness such-and-such phenom- 

 ena which are familiar to the inhabitants of 

 earth, the conclusion that such creatures do ex- 

 ist there. We do not assert that no such creat- 

 ures exist there. Our theory of life in other 

 worlds does not require that any given planet 

 should be shown to be uninhabited. Neverthe- 

 less, there are so many reasons for regarding the 

 fullness of Mars's life-bearing season as belong- 

 ing to a very remote past, that it is necessary to 

 note the insufficiency of the mere evidence of 

 the activity of Nature's unconscious forces to 

 prove the existence of living, conscious beings 

 on the planet. 



In fine, the arguments by which, in the essay 

 on " Life in Mars," we endeavored to indicate the 

 probability of the planet's being inhabited, prove 

 only that the planet had an origin like our earth's, 

 and is similarly constituted. 



On the other hand, the arguments by which, 

 in the essay entitled " A Whewellite Theory of 

 Mars," we endeavored to show that Mars is not 

 in a condition fit to be the abode of life, tend to 

 show that while similar to the earth in origin and 

 structure, Mars is in a far later stage of planetary 

 development. 



One of these arguments, indeed, does not re- 

 late to the condition of the planet itself, but to 

 its position with reference to the sun. Being 

 much farther from the sun than we are, the 

 planet receives much less direct heat. The sup- 

 ply is partly dependent, however, on the planet's 

 condition ; for, if the air of Mars is very rare, 

 then apart from the diminished supply there is a 

 more rapid cooling, owing to the readier radiation 

 of heat into space. But in any case the supply 

 of solar heat has to be considered as one of the 

 factors of a planet's condition, considered with 

 reference to the question of habitability. If, 

 through its inherent heat, the planet Mars was 

 once as warm on the whole as the earth now is, 

 that heat making up for the smaller supply of 

 solar heat, then it seems reasonable to believe 

 that the creatures inhabiting the planet were so 

 far like those now existing on our earth that the 



