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 crea- 

 tures 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 mechan- 

 ical 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 ex- 

 pressly with a view of 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 re- 

 ciprocal beneficence ? If then such, and such only, be admitted to be the pur- 

 poses and uses of our atmosphere, the question whether other planets, in situa- 

 tions resembling ours, are occupied by similar beings, must be materially influ- 

 enced by the result of an investigation as to whether or not these planets are 

 supplied with like atmospheres. 



Telescopic observations have most clearly and satisfactorily answered this 

 question. The atmosphere around the planets are as palpable to sight as the 

 clouds which float on our own. Venus and Mercury are enveloped in thick 

 atmospheres: in the former the air is especially conspicuous, nay, \ve can 

 even see the morning and evening twilight in that distant world. The atmo- 

 sphere of Mars is likewise apparent. We see the clouds floating on it. Ju- 

 piter and Saturn afford not less unequivocal manifestations of atmospheres ; 

 and if we have not the same clear and satisfactory evidence in the case of H/r- 

 schfil, we have abundant reason for the want of it, in its enormous distance and 

 the hitherto deficiency of telescopic power. 



The ascertained existence of clouds in the planets proves more than the 

 mere presence of atmospheres upon them. An atmosphere is necessary to sup- 

 port clouds, but must not be identified with them. Clouds are no more parts 

 of the atmosphere than the mud and sand which float in a turbid river are 

 parts of its waters. Water is converted into vapors by the agency of the sun 

 and wind. This vapor, when it escapes from the surface of the liquid, is gen- 

 erally lighter, bulk for bulk, than that part of the atmosphere contiguous to it. 

 It rises into more exalted regions, where, by the agency of cold, and by electri- 

 city, it is made to resume its liquid state, but in such minute particles that it 

 floats and forms those semi-opaque masses called clouds. Clouds are, then, in 

 fact, water existing in a very minute state of mechanical division, and affected 

 in peculiar ways by electricity. 



When these particles are caused to coalesce into drops or spherules of wa- 

 ter an efl'ect which may arise from temperature or electricity, or both combined 

 their weight renders their further suspension impossible, and they descend to 

 the surface in the form of rain ; or if the cold be so great as to congeal the par- 

 ticles before they coalesce into globules, they descend in the form of snow ; or. 

 finally, if by the sudden evolution of heat caused by electrical influences their 

 solidification is effected into drops, they come down in the form of hail. 



Thus wherever the existence of clouds is made manifest, there WATER must 

 exist; there EVAPORATION must go on; there ELECTRICITY, with its train of kin- 

 dred phenomena, must reign; Mere RAINS must fall; there HAIL and SNOW 

 must descend. 



That healthful and refreshing winds agitate the atmospheres of the group of 

 worlds in the centre of which our suu presides, and of which he is the common I 





