Voyage of a Drop of Water. 15 



Clouds. What drives vapor or clouds over the land ? 

 The wind. What causes the clouds to return and fall in 

 the form of rain ? The coldness of the air above us. If 

 you should ascend far above the earth's surface in a bal- 

 loon or by traveling up a high mountain, what differ- 

 ence would you find in the air ? We would find it cooler 

 and cooler the higher we go. 



8. From this you may readily understand how 

 a certain drop of water may be changed to 

 vapor, rise from the ocean, be carried by the 

 winds far away and over the land, changed back 

 to water, fall on the ground, sink down below 

 the surface, find its way to a spring, reappear in 

 the overflow, run down a hillside, and become 

 part of a rill, rivulet, brook, or other little 

 stream. The stream flows on, falls over steep 

 places, forming cascades or waterfalls, 

 turns mill-wheels, receives other streams, 

 becomes deep enough and wide enough to float 

 large steamboats, and at last finds its way 

 into the ocean. Thus that little drop of water, 

 after a long and curious journey, may return 

 to the place it started from. 



9. Can people live without water ? Does the water you 

 drink come from a spring, well, lake, reservoir, or river ? 

 From what is the well, spring, river, or lake supplied ? 

 Rain. From what does rain come ? From what do 

 clouds come ? 



SPELL AND DEFINE Brook, wheel, steep, 

 steamboat, cascade, balloon, rivulet. 



