2 PHYSIOGEAPHY 



Although the solid part of the earth, the water, and the air, seem 

 very distinct from one another, they are in reality not so sharply 

 separated as they seem. The larger part of the water is in the ocean, 

 lakes, and rivers; but some of it has sunk into the soil and rocks, and 

 a little of it is always to be found in the form of vapor, which we 

 cannot see, in the air. So, too, a part of the atmosphere penetrates 

 the soil and rocks of the land, and gases from it are dissolved in 

 the water. Solid matter from the land is found in water, often 

 making it muddy, and dust is always present in the atmosphere. 

 In spite of this mingling, the boundaries between the lithosphere, 

 hydrosphere, and atmosphere are usually well defined. 



