USES OF AN ATMOSPHERE. 



even had our atmosphere been so rare and attenuated as it is at 

 an elevation of three miles (scarcely one-tenth of its whole 

 height), the waters of our oceans would have been solid. Vege- 

 tation could never have existed, and in spite of the light and 

 genial warmth of the sun in spite of the grateful changes of 

 season in spite of the beautiful and simple provision by which, 

 spring succeeds winter, and is followed by summer and autumn, 

 the earth would have been a barren and arid waste, enve- 

 loped in a shell of eternal ice, devoid of life, motion, form, and 

 beauty. 



Seeing, then, how necessary to the existence of an animal and 

 vegetable world an atmosphere is how indispensable its presence 

 is to a society of creatures whose means of intercommunication 

 is sound and yet bearing in mind at the same time that this 

 atmosphere is not essential to any of the great mechanical 

 functions of the earth in the economy of the solar system 

 considering also that without its presence the part which that 

 earth, as a whole, performs in the society of the planets, would 

 be the same as it now is can we come to any other conclusion 

 than that this atmosphere was cast around the earth expressly 

 with a view to the well-being of its occupants to afford them 

 a genial warmth to give them diffused and gentle light to 

 convey the varieties of sound to promote and facilitate social 

 felicity, by supplying the means of intercommunication by- 

 language to preserve the seas liquid and supplying propitious 

 winds to stimulate the intercourse of nations and knit together 

 the races of beings who occupy its most distant points by the 

 kindly bonds of reciprocal beneficence] If then such be ad- 

 mitted to be some among the many of the purposes and uses 

 of our atmosphere, the question whether other planets, in 

 situations resembling ours, are occupied by similar beings,, 

 must be materially influenced by the result of an investi- 

 gation as to whether or not these planets are supplied with like 

 atmospheres. 



3. Telescopic observations have most clearly and satisfactorily 

 answered this question. The atmospheres around the planets 

 are as palpable to sight as the clouds which float on our own. 

 Yenus and Mercury are enveloped in thick atmospheres : in the 

 former the air is especially conspicuous, nay, we can even see 

 the morning and evening twilight in that distant world. The 

 atmosphere of Mars is likewise apparent. We see the clouds 

 floating on it. 



4. The ascertained existence of clouds in the planets proves 

 more than the mere presence of atmospheres upon them. An 

 atmosphere is necessary to support clouds, but must not be 



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