166 THE CHEMISTRY OF CREATION. 



aerial chemistry, that some particulars should be 

 mentioned as to the physical constitution of 

 our air. 



There are only one or two other planets of 

 our system beside the earth which are considered 

 to be provided with an atmosphere, or envelope 

 of gas. We cannot recognise in other systems 

 of worlds a similar provision, though doubt- 

 less it may exist in some altered form with- 

 out our being able to perceive it. What is 

 called " space " is considered to be destitute of 

 any fluid like our air, or indeed like any gas 

 with which we are acquainted. Our globe is 

 revolving on its own axis, at the immense rate 

 of, at the equator, upwards of 1,000 miles 

 an hour. It is also moving in its orbit at 

 a speed exceeding 68,490 miles in the hour. 

 Now if such be the case, if there is a vast air- 

 empty space above us, constantly attracting, or 

 endeavouring to attract, our air into it, and if, 

 in addition, the rapid motion of the earth lias 

 a tendency to scatter its airy garment to the 

 ends of heaven, as it undoubtedly has by virtue 

 of the centrifugal force, by what power is it 

 that the atmosphere nevertheless still closely 

 clings to our globe? And the same inquiry 

 is applicable to such other planets as may be 

 thus provided. The atmosphere travels .with 

 us, as with them, at an enormous velocity, 



