NATURAL HISTORY. 19 



affords a study highly delightful, and in a very 

 powerful degree calculated to impress on your 

 minds the grandeur of the design upon which the 

 universe was created, and the omnipotence of 

 Him by whom that design was carried into exe- 

 cution. 



The atmosphere is that invisible substance which 

 surrounds the globe in every direction to a con- 

 siderable elevation, whose influence is indubita- 

 ble, but whose presence will not admit of tangible 

 nor ocular demonstration. The science, by which 

 its properties are explained, has been denominated 

 pneumatics; or, if we embrace the whole of its 

 various phenomena, meteorology. Its mechanical 

 principles are fluidity, transparency, density, gra- 

 vity, and elasticity. Its component parts or 

 chemical principles are oxygen, nitrogen, and 

 carbonic acid ; in which nitrogen bears the great- 

 est proportion, and carbonic acid in a very conr 

 siderable degree, the least. By a knowledge of 

 its mechanical powers, we become acquainted 

 with the nature of wind or air set in motion, 

 which, when in excess, constitutes the storm or 

 the hurricane ; or, when applied to human pur- 

 poses, promotes navigation, the propelling of mill 

 machinery, and the like with its pressure upon all 

 material substances, by which they preserve their 

 position and equilibrium, each portion being con- 

 fined to its own proper sphere with the doctrines 

 of sound, &c. In a chemical sense, it is the great 



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