Makcu 27, 18S5.] 



KNOWLEDGE ♦ 



257 



ducing a current of 40 amperes, with an electromotive 

 force of 160 volts, while the motor absorbs 17 aniporos, so 

 that there is a considerable margin. It is estiuiatod that 

 in nine months the car has travelled some 25,000 miles. 

 Although only construct«»d to airry 30 passengers, it has 

 been known to carry 53, and on a single day 3,000 

 passengers have travelled the length of the line. So great 

 is the popularity of the undertaking, that in ten months 

 300,000 passengers have been carried. The fact of such 

 an extensive and continuous patronage is proof positive ihat 

 the line is an actual success, for there cin be no doubt 

 that the novelty has long since worn off for the great 

 majority of the travellers. Some of the townspeople have 

 made, and continue to make, strenuous etlorts to bring the 

 experiment to a close, the objection raised being that the 

 line is laid on the foreshore, which is ])ublic property. It 

 is to be hoped, however, that such objections will be over- 

 ruled. The line is in nobody's way, nor does it interfere 

 with the public use of the beach to any appreciable extent 

 — not ntarly so much, in fact, as do the hosts of boats 

 and bathiijg-machines which throng the beach. It is 

 gratifying to notioe that, from a monetary point of view, 

 Mr. Volk is in every way pleased. He finds that the 

 cost of haulage is but twopence per car-mile, while the 

 average earnings are one shilling and fivepencc — pro- 

 viding, therefore, an excellent margin for other expenses 

 incident to the sjstem. 



As might be expected, Mr. Volk has not been free from 

 trouble in connection with his railway. He experienced 

 considerable difficulty in getting his plant together; carriage- 

 builders were chary of building for a new venture, and 

 wanted to be pnid before commencing the work. Storms 

 on one or two occasions washed away a part of the line. 

 The last trouble of this kind took place abont a week before 

 Christmas, when a large portion of the line was washed 

 away and the beach removed by the waves. A tall viadact 

 was built to level the line again, but, as soon as this was 

 finished, back came the beach to even a grcatsr extent 

 than it had previously existed. 



As stated above, other electric railways have been con- 

 structed ; but this is given as a typical one, and as one in 

 which considerable difficulties have been overcome. 



We thall look forward to the time when electric rail- 

 ways will be as common as, perhaps, any other mode of 

 travelling. 



LIFE IN OTHER WORLDS. 

 By Richard A. Proctor. 



(C/jntinaed from p. 211.) 



AGAIN, if we compare any two members of the solar 

 system, except perhaps Venus and the Earth, we 

 cannot doubt th&t the duration of any given stage of the 

 existence of one must be very different from that of the 

 corresponding stage in the other. If we compare, for 

 instance, Mars with the Earth, or the Earth with Jupiter, 

 and still more, if we compare Mars with Jupiter, we cannot 

 doubt that the smaller orb of each pair must pass much 

 more rapidly through the different stages of its existence 

 than the larger. The laws of physics assure us of this, 

 apart from all evidence afforded by actual observation ; but 

 the results of observation confirm the theoretical conclu- 

 sions deduced from j^hysical laws. We cannot, indeed, 

 study Mars in such sort as to ascertain his actual physical 

 condition. We know that his surface is divided into 

 lands and seas, and that he possesses an atmosphere ; 

 we know that the vapour of water is at times present 

 in this atmosphere ; we can see that snows gather over 



his polar regions in winter and diminish in summer : 

 but we cannot certainly determine whether his oceans 

 are like our own, or for the most part frozen ; the whitish 

 light which spreads at times ovt-r land or sea may bo 

 duo to clouds or to light snow falls, for aught that ob- 

 fervation shows us ; the atmosphere may be as dense as 

 our own or exceedingly rare; the polar regions of the 

 planet may resemble the earth's polar regions, or may be 

 whitened l)y snows relatively quite insigiiilieaut in quantity. 

 In fine, so far as observation extends, the ]ihysical condi- 

 tion of Mars m>y closely resemble that of the earth, or be 

 utterly dissimilar. Itut wo have indirect observational 

 means of dtitermining the probable condition of a planet 

 smaller than the earth, and presumably older — that is, at 

 a later stage of its existence. For the moon is such a 

 j)lanet, and the telescope shows us that the moon in her 

 decrepitude is oceanless, and is either wholly without 

 atmosfhere or possesses an atmosphere of exceeding 

 tenuity. Hence we infer that Mais, which, as an exterior 

 planet, and much smaller than the earth, is probably at a 

 far later stage of its existence, has passed far on its way 

 towards the same state of d( crepitude as the moon. As 

 to Jupiter, though he is so much farther from ua than 

 Mars, we have direct observational evidence, btcauseof the 

 vast scale on which all the processes in progress on his 

 mighty globe are taking place. We see that his whole sur- 

 face is enwrapped in cloud-layers of enormous depth, and 

 undergoing changes which imply an intense activity (or, in 

 other words, an intense heat) throughout his whole mass. 

 We recogiiise in the planet's appearance the i-igns of as 

 near an approach to the conditions of the earth when, as yet 

 the gredter part of her mass was va|iorous, as is consistent 

 with the vast difference recessarily existing between two 

 orbs containing such unequal ipiautilies of matter. 



Mars, on the one hand, ditit-rs from the earth in being 

 a far older planet — p-atei///, as respects the actual time, 

 which has elapsed since the planet was formed, and cer- 

 tainhj as respects the stage of its career which it has now 

 reached. Jupiter, on the other hand, differs from the 

 earth in being a far younger planet — not in years per- 

 haps, but in condition. As to the actual age of Jupiter 

 we cannot form so probable an opinion as in the case of 

 Mars. Mars being an exterior jilanet, must have hegun 

 to be formed long before the earth, and, being a much 

 smaller planet, was probably a shorter time in attaining its 

 mature growth. On both accounts, therefore, he would be 

 much older than the earth in years; while, as we have 

 seen, his relative smallness would cause the successive 

 stages of his career subsequent to his existence as an inde- 

 pendent and mature planet to be much shorter. Jupiter, 

 being exterior to Mars, presumably began to be formed 

 millions of centuries before that plarl^t, but his bulk and 

 mass so enormously exceed those o£ Mars, that his growth 

 must have required a far longer time ; so that it is not at 

 all certain that even in point of 3 ears Jupiter (dating from 

 his maturity) may not be the youngest member of the solar 

 system. But even if not, it is practically certain that, as 

 regards development, Jupiter is far younger than any 

 member of the solar system, save ])erhaps his brother giant 

 Saturn, whose greater antiquity and inferior miss (both 

 suggesting a ktt^r stage of development) may have been 

 counterbalanced by a comparative sluggishness of growth 

 in the outer parts ot the solar domain. 



It is manifest from observed facts, in the case of 

 Jupiter, that he ia as yet far removed from the life- 

 bearing stage of planetary existence, and theoretical con 

 sideiaiions point to the same conclusion. In the case of 

 Mars, theoretical considerations render it extremely pro- 

 bable that he has long since passed the life-bearing stage, 



