INTRODUCTION 



heat and the electric waves. The Kinetic Theory of 

 Gases, now firmly established, showing the molecules 

 of all gases to be in constant, rapid, translatory mo- 

 tion, producing thereby the effects of the pressure and 

 expansion of gases, has a strong analogy with what 

 is supposed to be the Atomic structure of the Ether. 

 Our atmosphere, a gas, while preserving the indi- 

 vidual motion of its molecules and the statical pres- 

 sure of fifteen pounds to the square inch upon our 

 bodies, as upon all substances, is yet insensible to us 

 so long as the pressure on all sides is alike, yet it is 

 also the medium whose vibrations cause sound. All 

 production or conveyance of sound ceases with the 

 withdrawal of the air. Nature is parsimonious in 

 the employment of her Ministers. She requires of 

 the atmosphere not only the service stated, but 

 makes it also the reservoir of the oxygen we breathe, 

 the storehouse of carbon dioxide, kept therein until 

 wanted for the life of the growing plant, the supporter 

 of combustion, the distributor of water throughout 

 the land, and the conservator of heat; while the 

 winds thereof are their own conveyers of physical 

 motion, are the forces that move the waves, wrestle 

 with the forests, and scatter seeds and pollen through- 

 out the land. So also the Ether should have many 

 duties. It is the medium through which Life is given ; 

 whether only through the light and heat it brings, 



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