April 10, 1885.] 



♦ KNOWLEDGE ♦ 



295 



/=^ ^■; 



>^ AN ILLUSTRATED 



MAGAZINE OF SCIENCE 

 PlainlyWorded -exactlyDescribed 



LOXDOX: FRIDAY, APRIL 10, 1885. 



Contents op No. 180. 



PAGE 



Life in Other Worlds. By K. A. 



Proctor '. 295 



The KMevala. V. Br Edward Clodd 2&7 

 Is the Diarneter of the Pupil of the 



Eye an Equivalent for the Light's 



Intensity? By John GorhacD, 



M.R.C.5. Ene.' 299 



Rain. By R. A. Proctor 300 



The YouDE Electrician. (IUu9.) 



By W. SHn-ro 302 



Thought and Language. VII. Bt 



Ada S, Baliin .'. 30^1 



Oar Household Insects. (iZ/u«.) By 



E. A. Butler 305 



First Star LeeeoBfl. {With Map.) 



Bv K. A. Proctor 306 



Evolution of the Sense of Bi-autv. 



L By ConstaD.-e C. W. >'adon .".. 3<6 

 Chapters on Modem Domestic Eco- 

 nomy. (lUui,) 300 



Editorial Gossip 'mo 



Face of the Sky. ByF.R.A.S 311 



CorreBpoi-donce : The Dual Brain 

 and Dreaming— Infinity — The In- 

 telleet in Instinct and in Reason 

 —Hogarth's Line of Beauty, &c. . 311 



Our Inventors' Column 315 



Our Chess Colomn 316 



LIFE IX OTHER WORLDS. 

 By Richard A. Proqtor. 



(Continued from p. 259.) 



IN considering the case of Mars, I suggested the possi- 

 bility that, owing to the relative shortness of that 

 planet's life-sustaining era, the development of the higher 

 forms of life may have been less complete than on our 

 earth thus far (still less than the development of those 

 forms on the earth in coming ages). We may well believe 

 that during the long period of Jupiter's existence as a life- 

 supporting planet, creatures far higher in the scale of being 

 than any that have inhabited, or may hereafter inhabit, 

 the earth, will be brought into existence. As the rule of 

 nature on earth has been to advance from simple to more 

 complex forms, from lower types to higher, so (following 

 the argument from analogy) we must suppose the law of 

 nature to be elsewhere. And time being a necessary 

 element in any process of natural development, it follows 

 that where nature is allowed a longer time to operate, 

 higher forms, nobler types, will be developed. If this be 

 so, then in Jupiter, the prince of planets, higher forms of 

 animated conscious being will doubtless be developed than 

 in any other planet. We need not, indeed, point out that 

 the supposition on which this conclusion rests is merely 

 speculative, and that now, when the laws of natural 

 development have so recently begun to be recognised and 

 are still so imperfectly known, the argument from analogy 

 is (in this particular case) necessarily weak. Nevertheless, 

 analogy points in the direction we have indicated, and it is 

 well to look outwards and onwards in that direction, even 

 though the objects within the field of view are too remote 

 for us to perceive their real forms. 



But, limiting our conclusions to those which may be 

 justly inferred from known facts, let us inquire how the 

 subject of life in other worlds presents itself when dealt 

 with according to the relations above considered. 



It is manifest at once that whether our new ideas 

 respecting the present condition of Mars or Jupiter be 

 correct or not, the general argument deducible from 

 the analogy of our own earth remains unaffected. If 



I^Iars and Jupiter be at this moment inliiibited by living 

 (.rtiituros, it can only be because these orbs happen to be 

 passing through the life-supporting period of their existence. 

 Wo have shown that there is strong reason for believing 

 this not to be the case ; but if it is the case, this can only be 

 regarded as a strange chance. For wo have learned from 

 the study of our earth, that the life-stipporting era of a 

 planet is short 0(im|>arcd with the duration of the planet's 

 existence. It follows that any time selected at random in 

 the history of a planet is far more likely to belong to one or 

 other of the two lifeless eras, one preceding, the other fol- 

 lowing the lif(! supi)orting era, than to belong to this short 

 era itself. And this present time is time selected at random 

 with reference to any other orb in the universe than our 

 own earth. Wo are to apt to measure all the operations of 

 nature by our own conceptions of them, as well in space as 

 in time, that as tlie solar system presents itself (even now) 

 as the centre of the universe, so this present time, the era 

 of our own life, or of our nation's life, or of the life of man, 

 or of the existence of organic beings on the earth, or 

 (passing yet a grade higher) the era of our earth's existence 

 as a planet, jire.sents itself to us as the central era of all 

 time. But what has been shown to be false with re.spect to 

 space is equally false with respect to time. Men of old 

 thought that the petty region in which they lived was the 

 centre of the universe. After this was shown to be false by 

 Copernicus, Kepler, and Newton, men clung in turn to the 

 conception that the solar system is central within the 

 universe. The elder Herschel show, d that this conception 

 also is false. Even he, however, assigned to the sun a 

 position whence the galaxy might be measured. But it 

 begius to be recognised that this is not so. Nay, not only 

 is the sun no suitable centre whence to measure the stellar 

 system, but the stellar .system is for us immeasurable. The 

 galaxy has no centre and no limits ; or rather we may say 

 of it what Blaise Pascal said of the universe of space — its 

 centre is everywhere and its circumference nowhere. The 

 whole progress of modern science tends to show that we 

 must similarly extend our estimate of time. In former 

 ages each generation was apt to regard its own era as 

 critical in tlie earth'.s history ; that ii', according to their 

 ideas, in the history of the universe itself. Gradually 

 men perceived that no generation of men, no nation, 

 no group of nations, occupies a critical or central position 

 in the history of even the human race upon earth, far less 

 in the history of organic life. We may now pass a step 

 higher, anil, contemplating the infinity of time, admit that 

 the whole duration of this earth's existence is but as a 

 single pulsation in the mighty life of ths univer.se. Nay, 

 the duration if the solar system is scarcely more. Countless 

 other such systems have passed through all their stages, and 

 have died out, untold ages before the sun and his family 

 began to be formed out of their mighty nebula; countless 

 others will come into being after the life has departed from 

 our system. Nor need we stop at solar systems, since 

 within the infinite universe, without beginning and 

 without end, not suns only but .systems of suns, 

 galaxies of such system.s, to higher and higher orders 

 endlessly, have long since passed through all the stages of 

 their existence as systems, or have all those stages yet to 

 pass through. In the presence of time-intervals thus seen 

 to be at once infinitely great and infinitely little — infinitely 

 great compared with the duration of our earth, infinitely 

 little by cotnjiarison with the eternities amidst which they 

 are lost — what reason can we have when viewing any orb 

 in space from our little earth, for saying noio is the time 

 when that orb is, like our earth, the abode of life ? Why 

 should life on that orb synchronise with life on the earth t 

 Are not, on the contrary, the chances infinitely great 



