52 PHYSICAL SCIENCE BK. n 



to air, and air is the atmosphere in violent motion. 

 Now, though the air may enter the earth in order to 

 produce earthquakes, the treatment of earthquakes 

 does not fall under geography, but more properly 

 belongs to meteorology, which deals with the sphere 

 to which nature has assigned the atmosphere. I 

 can tell you something that will sound stranger 

 still : I must speak of the earth when dealing with 



4 the heavenly bodies. Why ? you ask. For this 

 reason : we discuss in their own proper place, as 

 part of geography, the properties of the earth, for 

 example, whether it is broad, projecting unequally 

 in a huge bulge to one side, or whether it all assumes 

 the shape of a ball, gathering up its parts into a 

 globe ; whether it binds its waters or is itself bound 

 by them ; whether it is an animal or a lifeless mass 

 without feeling, full of air no doubt, but not its own 



5 breath. These, and all other questions of the kind, as 

 often as they crop up, will be relegated to geography, 

 and be placed in the lowest category. But when 

 the question comes to be the situation of the earth, 

 the part of the universe in which it has settled, its 

 position with respect to the heavens and heavenly 

 bodies, then the inquiry will take its place in the 

 higher category, 1 and obtain higher rank so to speak. 



II 



HAVING described the three divisions into which all 

 the material of nature falls, I must add a few general 

 remarks on the subject. And this must be premised, 

 that the atmosphere belongs to the class of bodies 

 that possess unity. What exactly this means, and 



1 Viz. that of the heavenly bodies which constitute the subject matter 

 of astronomy. 



