220 THE ATMOSPHERE AND 31ETE0E0L0GY. 



PART II. 

 THE ATMOSPHERE AND METEOROLOGY. 



BOOK I.— THE AIR AND WINDS. 



CHAPTER I. 



AIR THE AGENT OF TFIE VITAL CIRCULATIOX OF THE PLANET. — PHENOMENA OP 

 ItEFLECTION AND REFRACTION. — illRAGE. 



Death and eternal silence would reign over all the earth if it were 

 deprived of the atmosphere that envelops of our planet. This gaseous, 

 transparent, and invisible mass, which scarcely seems to form a part 

 of the earth, is nevertheless its principal element. For it is the most 

 mobile, and it is by its agency that life is sustained. The earth sup- 

 ports us, but whether men, animals, or plants, we alike require the air 

 for our existence. Although not flying in it like birds, all living 

 beings, whether they walk, climb, or fix their roots in the soil, are 

 not the less children of the atmosphere. 



Considered as one of the heavenly bodies, our planet is composed 

 of a solid kernel surrounded by two fluid strata. The kernel is that 

 which bears more especially the name of the earth, it is the rocky 

 beds containing lava, molten metals, and the entire mass of un- 

 known substances which occupies the centre of the globe. The sheet 

 of water forming the seas and the network of rivers covers this solid 

 skeleton, and above this watery envelope is stretched a second spherical 

 layer still more fluid, and whose currents and counter-currents in- 

 cessantly circulate from the pole to the equator, and from the equator 

 to the pole, with the regularity of the lungs of man, by turns filled 

 and exhausted. The atmosphere is truly the breath of the planet ; 

 like its satellite, which most astronomers tell us is destitute of a gaseous 

 envelope, the earth would be only a dead star rolling in space if it 



