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tances, and the laws which regulate their stupendous 

 movements, belong to the sublime science of Astronomy. 

 The atmosphere snrrounding this earth, the waters which 

 cover so large a portion of its surface, the solid materials 

 of which the globe is composed, and the innumerable or- 

 ganic productions which clothe its surface, are the objects 

 which the natural historian examines and describes. 



A knowledge of the composition, properties, and phe- 

 nomena of the Atmosphere, throws much light on the 

 history and functions of animals, as this fluid is the great 

 medium through which oxygen, heat, light, electricity, 

 and all imponderable agents, the great springs of vital 

 phenomena, are conveyed to organized beings. It unfolds 

 to us the theory of respiration in all terrestrial and aquatic 

 Animals, and shows the cause of the variety of temperature 

 in the warm and cold-blooded classes. It explains to us 

 the migrations of Animals, the theory of their geographical 

 distribution, and many of their instincts and habits. It 

 illustrates the periodical changes in the plumage of Birds 

 and the furs of Quadrupeds, and the distribution of colours 

 over the animal world. The Atmosphere is the medium 

 by which sounds and odours are transmitted to sensitive 

 beings, and it is intimately connected with irritability, 

 the most general and the most inexplicable property of 

 animal matter. This fluid is indeed the most essential of 

 all the elements to the continuance of animal life, and is 

 abundantly supplied to every individual from the sum- 

 mits of the highest mountains to the greatest depths of the 

 sea. 



The Waters of the earth cover three-fourths of its sur- 

 face, and support a thousand times more animated beings 

 than people the atmosphere or the dry land. The ocean 

 covers vast plains, deep valleys and caverns, stupendous 

 mountains and precipices, rapid gulfs and whirlpools, a 

 rich and dense vegetation, a world of animals, and all the 

 other natural scenery presented by the exposed continents. 

 It is the great oxydizing principle of the metallic nucleus 



