12 



Tribunt Extras 



cury I Some say that !f only the atmosphere were very 

 tare which surrounds Mercury, that planet could pos- 

 sibly have life there. Tu the Torrid Zone, at a certain 

 liighf you reach the snow line, and above tbat line there 

 would seem to be no life ; bat yet it does seem possible 

 that life may exist and does exist there. 



But there is one circumstance that is overlooked in 

 that. lu reality when you go to the higher regions 

 vhere the air is so rare, the sun's rays are not dimin- 

 ished. The air docs not tret warm : it does not prevent 

 the heat from passing through it; it does not get warm, 

 end ir. the .-ha. le the air is cold. But iu the direct heat 

 of the sun expose your baud, and the heat is more in- 

 tense than is easily bearable. Even with snow and ice 

 covering the mountain tops, the face and hands are blis- 

 tered by the heat of the sun. We should have a more 

 intolerable contrast in Mercury than in the case of an 

 atmosphere like our own. There would be very intense 

 beat under the direct rays of the sun, and comparative 

 cold iu the shadow, and life would be almost unendura- 

 ble to us; and if the atmosphere of Mercury were so 

 thin there would be. evaporation of all the water, aud 

 that would be another condition opposed to ours. It 

 iipp.-ars to me that that difficulty is sufficiently great to 

 make us doubt whether life can exist on Mercury; I 

 will not say such life as can exist on the earth, but; any 

 ot the higher forms of life, underthese conditious. 



LIFE IN OTHER WORLDS. 



Mercury is a planet waiting for the time when life 

 may exist on it; when the sun'a heat sball be sufficiently 

 reduced, aud then life will bo as comfortable as it is on 

 ( anh. Heie \ve are introduced to considerations of great 

 importance in this point of view of life in other worlds. 

 Though life now exists on tho earth, there have be.eu 

 long successions of ages, during which life has not been 

 possible on, earth; and there may be long successions 

 of ages during which life will be tolerable on the planets. 

 A plain t j< intended to support life, but not for all time, 

 but lor a small poll Ion of the planet's existence. 



Now, coming t( tho gravity of tho planets. The 

 pravity of Mercury, ov ing to its smalluess, is so 

 reduced that one pound would only press about five 

 ounces; aud here we are introduced to a considera- 

 tion of tho Importance of gravity to ourselves. Wo 

 sometimes look on gravity and weight of matter as be- 

 JIIL' an inconvenience rather than otherwise, but if it 

 Were not for : raviij- we should be continually at a loss ; 

 objects would not stand firm, and we should stagger for 

 want of weight, and would be iu that difficulty which 

 we find in endeavoring to walk in water beyond a cer- 

 tain depth. As you know, divers wishing to walkabout 

 in deep water have iieavy weights attached, so as to 

 keep thi-m.-elves in place. 



It is an absolute necessity, therefore, that gravity 

 chould e.\i>i. ami what wo are in the habit of lookiug 

 upon as an incon\ . menco is, therefore, in reality, a 

 verv important part of Iho earth's economy. If tho 

 caithV gravity were reduced to that in Mercury all the 

 plants would Miller; flowers droop or keep their heads 

 erect according to their structure, and it is absolutely 

 i ' >-ai v to continuance In life that a plant whose 

 i r coni'.itiou !* '.hat of uprightness, should remain 



Pamphlet Scries. 



so, and that that which droop? gTionlfl droop fit a props* 

 angle. It is shown that if that were not the case tho 

 stamens and pistils would not be properly adjusted for 

 the fertilization of the germs. And so it has been re- 

 marked that the whole mass of the earth, from pole to 

 pole, is engaged in keeping the snowdrop, the crocus, 

 &?., iu their proper position. In the case of Mercury 

 gravity is so much reduced that all these things would 

 be changed. The same difficulty applies to the plansC 

 Mars, which is so much smaller thau the earth. 



THE CHARACTERISTICS OF THE PLANET VENUS. 



But I now pass from Mercury to tho next planet, 

 Venus. Venus is the most beautiful, and we would 

 imagine from ordinary appearances to be the noblest ol 

 all except the sun and our moou. You will remember 

 Milton's words: 



Now yloive ! the firmament 

 With living snpphires: Herperu*, that kd 

 The staiy_v bost, ruile lirig.itest. * * * 



But Venus, examiued by tiie telescope, docs not re- 

 ward the astronomers so well as you might expect. She 

 Is too gloriously illuminated by the sun, and the applica- 

 tion of the telescope is disappointing. Again, we never 

 see Veuus under proper conditions. You never see the 

 whole portion of the illuminated surface. Look at this 

 diagram. You have the path of the earth here, aud 

 the path of Venus is inside. Wuen Venus is nearest 

 to the earth tho sun lies in the same direction, 

 and therefore Venus turns her darkened siile and can- 

 not be seen. When beyoud the sun his brightness 

 obscures her. The only time Venus can be studied ia 

 when she is on the two opposite sidss of her path, and 

 then she is seen either as a gibbous moon or a half moon. 

 We know, with respect to Venus, that she, being very 

 much nearer to the sun than the earth is, must have a 

 great deal more heat. Her heat is not so great as that 

 of Mercury; still she has twice as much heat as the earth 

 has. Iu other respects Venus is more like the earth. 

 Although Veuus has no moon, yet being nearer the sun 

 she must have tides, and they are barely comparable 

 with those that exist on the earth. 



But there is one peculiarity iu the condition of Venus 

 that seems very unfavorable to life, as we know it here. 

 According to the observations of the Italian astronomers, 

 who seem to have been able to see spots on Venus, (pro- 

 bably on account of tha clearness of tho atmosphere.) 

 which we cannot see at all iu England, tho axis, instead 

 of being sloping at a small angle, is much inclined. 

 Only for a short time would she have equal day anl 

 night, but when tho northern pole is toward ths i;uii, all 

 the polar pans would bo continually turno 1 toward the 

 sun; not merely a small part, but vory nearly half of 

 the planet on that side. When the southern polo would 

 bo turned toward the sun, that si.lo would have a con- 

 tinual day, and there would be continual night over 

 nearly half of tho planet. So there would be a very 

 great change iu tho condition of the planet in Winter aud 

 Summer. The 3 ear of Veuus is about seven and a half 

 months. It must be remembered that this sunshines 

 with twice the size and gives out twice tho heat that it 

 does to tho earth. The change between the two condi- 

 tions of W inter and Summer would bo even more serious 

 than the extreme heat and cold in either couditiou. In 



