253 



♦ KNOWLEDGE ♦ 



[March 27, 1885. 



and observed facts, though, they do not afiTord strong 

 evidence in favour of this canclusion, suggest nothing 

 which, rightly considered, is ojiposed to it It ij true that, 

 as we have shown in former essays on this planet. Mars 

 presents many features of resemblance to our earth. This 

 planet rotates in a period not difllring much from our 

 day ; his year does not exceed ours so greatly as to suggest 

 relations unpleasantly affecting living creatures ; it has 

 been shown that there are oceans on Mars, though it is not 

 quite so clear that they are not for the most part frozen ; 

 he has an atmosphere, and the vapour of water is at times 

 present in that atmosphere as in ours ; clouds form there ; 

 snow falls, and perhaps rain from time to time ; ice and 

 wnow gather at the poles in winter, and are partially 

 melted in summer ; the land surface must necessarily be 

 uneven, seeing that the very existence of continents and 

 oceans implies that once, at any rate, the globe of Mars 

 was subjected to forces resembling those which have pro- 

 duced the irregularities of the earth's surface ; glacial 

 action must still be going on there, even if there is no 

 rainfall, and therefore no denuding action corresponding 

 to that which results from the fall of rain on our terrestrial 

 continents. But it is a mistake (and a mistake too com- 

 monly made) to suppose that the continuance of those 

 natural processes which are advantageous to living crea- 

 tures, implies the existence of such creatures. The assump- 

 tion is that the beneficent processes of nature are never 

 wasted according to our conception?. Yet we see over and 

 over again in nature not merely what resembles waste, 

 what in fact /s waste according to our ideas, but an enor- 

 mous excess of wasted over utilised processes. The sun 

 pours forth on all sides the supplies of light and heat 

 which, where received as on our earth, sustain vegetable 

 and animal life ; but the portion received by our earth is less 

 than the 2,000 millionth, the portion received by all the 

 planets less than the 230 millionth part, of the total force 

 thus continually expended. And this is typical of nature's 

 operations everywhere. The earth on which we live illu- 

 strates the tiuth as clearly as the sun. We are apt to say 

 that it teems with life, forgetting that the region occupied 

 by living creatures of all orders is a more shell, while the 

 whole interior mass of the earth, far larger in volume, and 

 undergoing far more active processes of change — teeming 

 in fact with energy — contains no living creature, or at 

 least can only be supposed to contain living creatures by 

 imagining conditions of life utterly different from those we 

 are familiar with. 



The mere continuance, therefore, on Mara of processes 

 which on the earth we associate with the existence of life, 

 in reality proves nothing as to the continued existence of 

 life on Mars. The surface of the moon, for example, must 

 undergo disturbances, — mighty throes, as the great wave 

 of sun-distributed heat circles round her orb once in each 

 lunation, — yet few suppose that there is life, or has been 

 for untold ages, on the once teeming surface of our com- 

 panion planet. The formation of Mars as a planet must 

 so long have preceded that of our earth, his original heat 

 must have been so much less, his small globe must have 

 parted with such heat as it once had so much more rapidly, 

 Hars lies so much farther from the sun than our earth 

 does, his atmosphere is so much rarer, his supply of water 

 (the temperature conserving element) is relatively as well 

 as absolutely so much smaller, that his surface must be 

 utterly unfit to support life in the remotest degree re- 

 sembling the forms of life known on earth (save, of course, 

 those lower forms which from the outset we have left out 

 of consideration). Yet at one time, a period infinitely 

 remote according to our conceptions of time, the globe of 

 Mara mu«t have resembled our earth's ia warmth, and in 



being disturbed by the internal forces which cause that 

 continual remodelling of a planet's surface without which 

 life must soou pass away. Again, in that remote period 

 the sun himself was appreciably younger ; for we must 

 remember that although, measured by ordinary time- 

 intervals, the sun seems to give forth an unvarying supply 

 of heat day by day, a real process of exhaustion is in 

 progress there also. At one time there must have existed 

 on Mars as near an approach to the present condition of 

 our earth, or rather to her general condition during this 

 life-supporting era of her existence, as is consistent with 

 the difference in the surface gravity of the planets, and 

 with other differences inherent as it were in their nature. 

 Since Mars must also have passed through the fiery stage 

 of planetary life, and through that intermediate period 

 when, as it would seem, life springs spontaneously into 

 being under the operation of natural laws not as jet under- 

 stood by us, we cannot doubt that when his globe was thus 

 fit for the support of life, life existed upon it Thus for a 

 season, — enormously long compared with our ordinary 

 time-measures, but very short compared with the life- 

 supporting era of our earth's career, — Mars was a world 

 like our own, filled with variotis forms of life. Doubtless, 

 these forms changed as the conditions around them changed, 

 advancing or retrograding as the conditions were favourabhi 

 or the reverse, perhaps developing into forms corresponding 

 to the various races of men in possession of reasoning 

 j)Owers, but possibly only attaining to the lower attributes 

 of consciousness when the development of life on Mars was 

 at its highest, thenceforth passing by slow degrees into 

 lower types as the old age of Mars approached, and 

 finally perishing as cold and death seized the planet for 

 their prey. 



In the case of Jupiter, we are guided by observed facts 

 to the conclusion that ages must elapse )>efore life can be 

 possible. Theory tells us that this mighty planet, ex- 

 ceeding the earth three hundred limes in mass, and con- 

 taining five-sevenths of the mass of the whole system of 

 bodies travelling around the sun, must still retain a large 

 portion of its original heat, even if we suppose its giant oi b 

 took no longer in fashioning than the small globe of our 

 earth. Theory tells us, moreover, that so vast a globe 

 could not possibly have so small a density (less than one- 

 fourth the earth's) under the mighty compressing force of 

 its own gravity, unless some still more potent cause were at 

 work to resist that tremendous compression — and this force 

 can be looked for nowhere but in the intense heat of the 

 ])lanet's whole mass. But observation shows us also that 

 Jupiter is thus heated. For we see that the planet is sur- 

 rounded by great cloud-belts such as our own sun would bn 

 incompetent to raise, — far more so the small sun whicb 

 would be seen in the skies of Jupiter if already a firmament 

 had been set " in the midst of the waters." We see thac 

 these belts undergo marvellous changes of shape and colour, 

 imjilying the action of exceedingly energetic forces. We 

 know from observation that the region in which the cloud- 

 bands form is exceedingly deep, even if the innermost 

 region to which the telescope penetrates is the true surface 

 of the planet — while there is reason for doubting whether 

 there may not be cloud-layer within cloud-layer, to a depth 

 of many thousand miles, — or even whether the planet has 

 any real surface at all. And, knowing from the study cf 

 the earth's crust that for long ages the whole mass of our 

 globe was in a state cf fiery heat, while a yet longer peri( d 

 preceded this when the earth's globe was vaporous, we inf( r 

 from analogy that Jupiter is passing, though far moic 

 slowly, through stages of his existence corresponding with 

 terrestrial eras long anterior to the appearance cf life upn 

 the scene. ' 



