THE EARTH'S CLOTHING. 3 



we see the sand is laid in layers and curious streaks 

 and lines, and that it appears to extend to an indefi- 

 nite depth. We have learned another truth : The 

 ground is rough rock that splits into irregular slabs, or 

 is loose sand. We have not travelled a mile, and 

 already we have learned two facts. We have also 

 learned that one observation was not enough. The 

 second observation showed that we should be entirely 

 wrong if we concluded, from the first observation, that 

 the entire world was made of splintery rock full of 

 sparkling mica. It is clear we must go on, or make 

 still another mistake. Already we have learned a 

 good rule in observing nature : The whole truth is 

 found only after many obsenmtions. 



If you live in Chicago, or Portland, Me., or Port- 

 land, Ore., or in some other place, look about in the 

 streets, or if your home is in the country, around 

 the house, and make four observations, in four dif- 

 ferent directions, and find out whether the ground is 

 rock or sand or something else. If we are in New 

 York, we may extend our explorations a little farther. 

 Walking west through the street, we come in time to 

 the Hudson River. From the end of the docks we 

 can look across the water, and see a steep wall of dark 

 rock stretching along the bank of the river. There 

 are trees and perhaps houses to be seen on top ; and 

 at the foot of the black cliffs, near the water, there 

 appears to be a gentle slope covered with trees or 

 grass. We know that this wall of rock is called the 

 Palisades, and even at this distance we can see that 



